OAR Box 1830 

Prepped by Ollie Stewart 

Document Number: 

112)IV-C-78 

Docket Number: 

A-87-11 

p.i 

- y 

Printed 11/13/2008 7:20:57 AM Sheet 112 of 232 
P.2 

FEB I 6 1983 . 

SDSBrPassavantrbrayboy:2565 Plymouth Rd.:X408:2/1C/88:ID#:5706W 

Last reviewed by Charles Gray:2/11/88 

Mr. Barry Pelrice 

Associate Administrator tor Rulercakinq. 

National Highway Traffic Safety Administration 

400 Seventh St.", SW (HRM-10) 

V/a shiner con, DC 20590 

Dear Kr. Pelrice : 

Tnank you for your February 5, 1938 co^fntr. on HPA'P 

craft Scop? of Work regarding fuoi system comparative rink 

esse sftissnts. V?e appreciate! the time'vo u sne your tit a^f have 

investe:? in thin- review, nn-:1 *<?e have raodifiec? the Scope cf !-5ork 

ns su resented in your letter . A copy of the reviserl Scc-po of 

""or!; ip eno?osee. 

However, we ar e concerns-? about your statement that' -. . . 

o^r {NHTSA} comments shouXc not be --crns* trued a" our e.e'reeP'.ent 

tha t the product* of the study vii.I satisfactoril y -'.lefine the 

riffk? associate d with the .system**.H As vou know, thi" cor.tr-sct 

effort i ss de*?if^ne'"i v>rin**irilv to si? ."3 ess oot entis]! j;*.'**- efcv 

concerns tor enh03r6-eqr»ipped vehicle**, and ths? Scoroe of V'crk 

was prendre'-: based Ic*rr.*e!5.y on technica l input:- fro.'*; F^T^?., 

IIHfi, an''-! ofcherr-. Xt i ? our oesir ? to

 (.'<e. r ner ini t j ve 

gr«aiynis, end -ve co not w.-jp.t. *:.o overlook env coi;T"err>"" veich vou 

«}=jvf; identifie d ono ar e not addresser? 'nv the effort ue*~crimed 

in our Scope of t-'on;. Toward tha t ene, we v-ouici nnr-'-ecist? 

VOL--- r*uggestior3 as to v/hat els e shoulcl be addee1 to the £cepe 

of Vi'orfc. 

TnanU you for your cooperation, in this F>atter. A tiir.ely 

response would be appreciated sinc e the contracto r ir, now se t 

to begin work. 

Sincerel y yours, 

ORIGINAL SIGNED BY 

RICHARD D. WILSON 

Richard D. Wilson 

Director, Office of -Mobile Source:? 

Enclosure 
P.3 

\ \ 1988 

Jaraes 3ritell . .-

Federal Highway Administration"* — -•*"""'" 

Office of Motor Carrier Safety (8CS-10) 

400 Seventh St S.8. 

Washington, D.C. 20590 

Dear Sr. Btitell: 

As a follow-on to SPA*s previous onboard safety analysis 

and subsequent comment and discussions received 3t the publilc 

hearing, EPA has drafted the enclosed scope of work for a 

contract work assignment to assess the safety aspects and riPkc 

of various onboard control aporoaches in comparison to sever?*"! 

design features found in current fuel systesi confiaurationfj. 

This scope of work has been drafted to assess factors which vou 

and others have suggested are important in evaluating the 

safety implications of onboard controls. However, I want to be 

sure that all ootential concerns that can he addressed in an 

effort of this nature ar? covered. Therefore, I would 

appreciate it if you could take the time to review this 

document and provide us any cormnento or suggestions you -sight 

have. For your information, this scope of work has already 

been reviewed by NHTSA and incorporates their comment-?. Thank 

vou for your cooperation. 

Sincerely yours, 

ORIGINAL SmF- r 

. CHARLES LGfth":.

 :

 .. 

Charles L. Gray, Jr. 

Director 

Emission Control Technology Division 

Enclosure 

SDSB : Passavant :Dillingbam:2565Ply*T>outhRd.:X.408:2/19/88:ID#5750W 

Last reviewed by Charles Gray: 
P.4 

MAR I 1988 

Clarence M. Ditlow „^ ., 

Executive Director '.'" "*---*" 

Center for Auto Safety 

2001 S. Street sw, Suite 410 

Washington, D.C. 20009 

Dsar Mr. Ditlow: 

As a follow-on to EPA's previous onboard safety analysis 

and subsequent consent and discussions received at the public 

hearing, EPA has drafted the enclosed scope of work for a 

contract work assignment to assess the safety aspects and risks 

of various onboard control approaches in comparison to several 

design features found in current fuel system configurations. 

This scope of work has been drafted to -5s?5ess factors which you 

and others have suggested ars important in evaluating ths 

safety implications of onboard controls. Rovever, I want to he 

sure that all potential concerns that can ba addressed in an 

effort of this nature are covered. Therefore, I would 

appreciate it if you could t*ske the time to review this 

document and provide un any comments or suggestions you wight 

h3V5. For your information, this scope of v*ork has already 

been reviewed by NHTSA and incorporates their co-n-nente. Thank 

vou ^or your cooperation. 

Sincerely yours, 

ORIGINAL SIGNED BY 

CHARLES L. GRAY, JR. 

Charles L. Rray, Jr. 

Director 

Emission Control Technology Division 

Enclosure 

SDSB:Passavant:Di11ingham:2565PlymouthRd.:X408:2/19/88:IDf5750W 

Last reviewed by Charles Gray: 
P.5 

MAR ! 1988 

Brain O'Neill 

Presiden t .•"•*'-... 

Insurance Institute for Highway Safety 

Watergate 600 

Washington, D.C. 20037 

Dear Mr. Ocelli: 

As a follow-on to SPA's previous onboard safety analysis 

and subsequent comment and discussions received at the puMic 

hearing, EPA has drafted the enclosed scope of work for a 

contract work assignment to assess the safety aspects and risks 

of various onboard control approaches in comparison to several 

design features found in current fuel syster* configuration!?. 

This scope of work has been drafted to assess factors which vou 

and others have suggested are important in evaluating the 

safety implications of onboard controls. However, I want to he 

sure that all ootential concerns that can be addressed in an 

effort of this nature are covered. Therefore, T would 

appreciate it if you could take the time to review this 

document and provide us any comments or suggestions you might 

have. For vour information, this scope of work has already 

been reviewed by NHTSA and incorporates their com-r.ents. "-hank' 

you for your cooperation. 

Sincerely vours, 

ORIGINAL SIGNED BY 

CHARLESL GftA>. JR. 

Charles h. Cray, Jr. 

Director 

Emission Control. Technology Division 

Enclosure 

SDSB -Passavant :Dillingham-2565Plyn!outhRd.:X4 08: 2/19/88 :ID#57«50W 

Last reviewed by Charles Gray: 
P.6 

MAR I 1988 

Dr. Herritt Birkey 

National Transportation Safety Board 

Bureau of Technology * < ^^„>_ —• * 

TB-70 

800 Independence Avenue, SW 

Washington, D.C. 20*594 

Dear Dr. Sirkey: 

As a follow-on to EPA's previous onboard safety analysis 

and subsequent comment and discussions received at the public 

hearing, SPA has drafted the enclosed scope of work for a 

contract work assignment to assess the safety aspects and risks 

of various onboard control approaches in comparison to several 

design features found in current fuel systen configurations. 

This scope of work has been drafted tc assess factors which you 

and others have suggested are important in evaluating the 

safety implications of onboard controls. However, I want to be 

sure that all potential concerns that can be addressed in an 

effort of this nature are covered. Therefore, I v/ould 

-jppreciate it if you could take the time to review this 

document and provide us any comments or suggestions you right 

have. Por your information, this scope of work has alreadv 

been reviewed by NHTSA and incorporates their comments. Thank 

you for your cooperation. 

SincereIv yours, 

ORIGINAL SIGNED BY 

CHARLES L. GRAY, JR. 

Charles I.. Gray, Jr. 

Director 

Emission Control Technology Division 

Enclosure 

SDSB:Passavant:brayboy:2565PlyraouthRd.:X408:2/25/88:ID#5750W 

Last reviewed by Charles Gray: 
P.7 

Fuel System Comparative Risk Assessment 

Scope of Work 

I. Background 

On August 19, 1987, the Environmental Protection Agency 

(EPA) published a Notice of Proposed Rulemaking (NPRM) for a 

vehicle-based program to control refueling emissions. This 

rulemaking would require motor vehicle manufacturers to equip 

their gasoline-powered vehicles with hardware (i.e., onboard 

control systems) to control refueling emissions to a maximum 

level of 0.10 grams of vapor per gallon of dispensed fuel. The 

onboard control systems demonstrated to date provide a seal at 

or within the fillneck and route the gasoline vapors in the 

fuel tank to a carbon canister for storage, and later purge 

these vapors in the engine during operation of the vehicle. 

Over the past year, several parties have expressed concern 

regarding the safety of the proposed onboard refueling emission 

control systems. These parties have commented that adding 

canister-based onboard controls to motor vehicles would add 

some complexity to current fuel systems which could increase 

the risk of crash and non-crash fires for motor vehicles. In 

response to these concerns, EPA conducted an evaluation of the 

safety implications of canister-based onboard systems which was 

released for public comment as part of the NPRM. 

This is the first of three work assignments planned for a 

further assessment of refueling emissions, refueling emission 

control techniques, and their safety implications. This, the 

first work assignment, will require the contractor to assess 

the safety aspects and risks of onboard control systems 

compared to those now accepted by manufacturers in current (or 

past) fuel system designs.* The second and third work 

assignments (to follow) will assess vehicle refueling 

emissions, onboard refueling emission control technology, and 

the safety of the refueling operation itself under several 

scenarios. 

II. Description of Task 

The purpose of this work assignment is to prepare a 

comparative risk assessment for various onboard control 

approaches versus design features found in current fuel system 

configurations. This assessment will compare the potential 

risks from the addition of onboard controls to those risks 

manufacturers have already accepted as a result of recent 

changes in current fuel systems.* The following description of 

the work assignment will first outline the work approach and 

then detail the evaluation phases and fuel system 

configurations which shall be analyzed by the contractor. 

* It should be noted that the level of risk accepted by a 

manufacturer may not be regarded by NHTSA as safe for the 

purposes of enforcing the Vehicle Safety Act. 
P.8 

A. Work Approach 

The contractor shall perform an analysis comparing the 

risks related to adding onboard controls to current vehicle 

fuel systems relative to those incurred as a result of other 

recent fuel system design modifications. To aid in this 

assessment a baseline vehicle/fuel system is defined and a 

number of different modifications to the baseline system. are 

described. In each case, the modification is to be evaluated 

incremental to the baseline vehicle fuel system (not 

cumulatively) and the incremental risks encountered for each 

modification are to be compared. As a final subtask absolute 

comparisons will be conducted among some configurations. 

However, in general, the risk comparison is among the various 

modified baseline vehicle/fuel system configurations. For 

purposes of this analysis, risk is defined as the likelihood of 

potential problems resulting in a liquid fuel or vapor leak, 

with special emphasis placed on liquid leaks at rates greater 

than five ounces per five minutes (5 oz/5 min), which is the 

rate specified for FMVSS 301 crash testing. Special emphasis 

for vapor hazards assessments should focus on situations where 

significant amounts of vapor in flammable concentrations might 

exist near ignition sources. 

Risks will be determined through the use of a Failure 

Modes and Effects type of Analysis (FMEA) for each 

configuration. The FMEA is to be conducted for the baseline 

vehicle/fuel, system and the baseline vehicle/fuel system with 

each modification. In each case the FMEA should consider both 

the individual components and the full system. The FMEA shall 

include a) identifying potential problems, b) evaluating 

whether such problems could conceivably result in liquid fuel 

or vapor leakage, c) if so, assessing the likelihood of 

occurrence for such potential problems and d) assessing the 

likelihood that such occurrences would result in the release of 

gasoline from the vehicle's fuel system or in vapor release. 

Special emphasis areas for these hazards are as described in 

the previous paragraph. 

The likelihood estimates (e.g., probability/frequency) for 

the analysis shall be based on the best available information 

regarding the performance of analogous systems and/or 

components including manufacturing and in-use data (e.g. 

service bulletin/recall data) and other engineering analyses. 

For potential problems involving systems/components . where 

information is not available to accurately make the likelihood 

assessments mentioned above, (such as new hardware unlike any 

currently used on vehicle fuel systems) the contractor shall 

use good engineering judgment in making the determinations and 

shall document the basis for such judgments. As is discussed 

in more detail below, the FMEA should be conducted for three 

separate phases of the fuel system life cycle. 
P.9 

Following completion.of the FMEA for each configuration, 

the risks for all configurations evaluated shall be ranked on a 

relative basis. Ranking shall be done for each evaluation 

phase and then for overall risk (total for all three phases), 

among all configurations. To facilitate the development of 

these rankings, the contractor may choose to develop a scale by 

which to rate the likelihood of occurrence for each potential 

problem. Any scale used should be compatible with (and 

referencible to) any probability/frequency data used, such that 

all potential problems (within each phase, for each 

configuration), can be evaluated against a common scale and the 

risk for each individual problem can be expressed on a common 

basis. 

Following completion of the FMEAs and development of the 

rankings, a written report should be prepared. Risks shall be 

compared and discussed qualitatively among the various fuel 

system configurations evaluated to highlight any relative 

differences and changes. This comparison should be conducted 

for each evaluation phase and for the total risk for all 

configurations. For purposes of this report, any risk rankings 

should list values normalized back to that derived for the 

baseline rather than reporting specific numerical risk values 

for the risk in each phase and overall. 

B. Evaluation Phases 

In order to evaluate the overall potential risk of liquid 

fuel or fuel vapor leakage from a fuel system configuration, it 

is necessary to analyze the possible problems which may occur 

in all phases of the fuel system life. For purposes of this 

analysis, the evaluation phases considered in determining the 

overall risk should include design, manufacturing and in-use 

service. These three evaluation phases will be further 

described in the following sections. 

1. Desiqn Phase 

The Design portion of the analysis should quantify the 

risk of liquid fuel or vapor leakage (with special emphasis as 

described above for each configuration. The analysis should 

identify possible failure modes and their causes, the 

likelihood of the occurrence of such failures and the 

likelihood that such failures would result in fuel or vapor 

leakage. All potential vapor and fuel leakage should be 

assessed, with special emphasis as described above. 
P.10 

2. Manufacturing Phase 

The Manufacturing portion of the analysis should quantify 

the risk of potential liquid fuel or vapor leakage risk 

associated with the manufacturing of each fuel system 

configuration. The analysis should include component 

fabrication, component assembly, system assembly (all when 

applicable) and installation on the vehicle. As before, the 

analysis should identify possible failure modes and their 

causes, the likelihood of the occurrence of such failures and 

the likelihood that such failures would result in liquid fuel 

leakage. All potential vapor and fuel leakage should be 

assessed, with special emphasis as described above. 

3. Service Phase 

The Service phase of the analysis should quantify the 

in-use risk of liquid fuel or vapor leakage for each fuel 

system configuration. The analysis should evaluate all in-use 

problems which could cause fuel or vapor leakage from the 

particular fuel system configuration. Such in-use problems 

include but are not limited to the durability of the system and 

its components, system tampering, malmaintenance, unperformed 

scheduled maintenance, problems associated with refueling, 

motor vehicle accidents, and improper repairs. The analysis 

must consider both collision and non-collision problems and 

potential problem which could occur during refueling. The 

analysis should identify the possible problems and failure 

modes, the likelihood of the occurrence of such failures, and 

the likelihood that such failures would result in fuel or vapor 

leakage. As before, all potential vapor and fuel leakage 

should be assessed, with special emphases as described above. 

These three analyses shall be performed on every fuel 

system configuration specified. Based on these analyses, the 

overall risk of each fuel system design can then be determined. 

C. Fuel System Designs 

This work assignment should provide a comparative risk 

assessment of several fuel system configurations. The designs 

used in the assessment will involve a base case fuel system and 

several modifications of this system. These modifications 

include various current fuel system features and onboard 

control designs. The fuel system designs will be described in 

detail below. 

1. Base Case Vehicle/Fuel System 

It is important to note again that the base case fuel 

system and hardware described below will be the basis for all 

other fuel system configurations used in this assessment. The 

other fuel system configurations will modify this base case 

with fuel system features found on other current vehicles or 

with onboard vapor recovery systems. 
P.11 

The base case vehicle is a production 1986 Oldsmobile 

Cutlass Ciera with a carbureted 2.8L (VIN X) engine. The 

carbureted version of this vehicle with a 2.8L (VIN X) engine 

has a mechanical fuel pump under the hood near the engine. The 

vehicle has a side-fill fuel tank and is equipped with 

evaporative emission controls. The fuel tank and fillpipe 

configuration of this production vehicle, shown in Figure 1, 

includes an external vapor line on the fillpipe and a rubber 

connector in the fillpipe. The base case fuel system design 

will be exactly like the production fuel system design found on 

this vehicle. To gain further information on the system.'s 

design and components, the base vehicle stated above should be 

procured and examined and as well as any other extra parts 

which may be needed to gather further details. Some additional 

information on the fuel system design is presented in the 

appendix. 

2. Base System with Steel Fillpipe 

This fuel system configuration is the same as the base 

system with the exception of the fillpipe. The fillpipe on 

this design is the same as that on the production vehicle, 

except that it is constructed entirely of steel as are 

fillpipes on some present vehicles. 

3. Base System without External Vapor Line 

This fuel system configuration is the same as the base 

system described above (Fuel System No. 1) except that it 

eliminates the external vapor vent line from the fuel tank to 

the fillneck.. Instead, refueling vapors are routed internally, 

within a properly sized fillpipe. 

4. Base System without Rollover Valve 

This fuel system configuration is the same as the base 

system except that it excludes the mechanical rollover valve 

assembly for the evaporative emissions line. This valve is 

built into the fuel sending unit on the base vehicle. This 

rollover valve is replaced by a limiting orifice and "bow-tie" 

design anti-syphoning vapor line configuration used on.the 1985 

version of this vehicle. (See Figure 2a for a picture of the 

valve removed). 

5. Base System with Partially Submerged Fillpipe 

This fuel system configuration is the same as the base 

system with the exception of the connection of the fillpipe to 

the fuel tank. In this particular configuration, a steel 

length of fillpipe is connected to the fuel tank at a low 

enough level so that it is covered by the fuel during a portion 

of the refueling event and during subsequent operation. A 
P.12 

design similar to that used by Nissan (Figure 2b) should be 

considered.. Such a submerged fillpipe configuration is found 

on the 1987 Nissan 300ZX. In this design, the fillpipe enters 

the tank at the 42 percent capacity level. See Figure 2c for a 

similar design on a 1985 Jeep Cherokee which should also be 

considered. 

6. Base System with Fuel Injection 

This fuel configuration is the same as the base system 

with the exception that it uses a port fuel injection system 

instead of a carburetor to mix the fuel with the intake air. 

This fuel injection system is found on the version of the 1986 

Oldsmobile Cutlass Ciera with a 2. 8L engine which uses port 

fuel injection. As a result of using the fuel injection 

system, there are a few changes from the base case for the 

design of this fuel system. These changes include 

modifications to the fuel tank unit to insert the fuel pump 

within the fuel tank, addition of a pressure regulator, 

pressurized fuel line to the engine, fuel return line from the 

engine to the tank, and modification of the evaporative 

system. More details on this system can be found in the 

Appendix. 

7. Base System with Fully Integrated Onboard System 

(Liquid Seal/Fillneck-Mounted Rollover/Vent Valve) 

This fuel system configuration requires several 

modifications to the base system because of the incorporation 

of a fully integrated onboard control system with a 

fillneck-mounted. rollover/vent valve. A fully integrated 

onboard system is a system where vapors resulting from 

refueling are stored in the same, vapor storage unit as that 

used for the fuel tank and carburetor evaporative emissions of 

the vehicle. The modifications necessary for this system 

include the addition of a sealing mechanism for the- fuel 

system, the addition and enlargement of some vapor vent lines, 

the addition of a rollover valve, and the enlargement of the 

charcoal canister. This system is shown graphically in 

Figure 3, and is described in more detail in the Appendix. 

8.a Base System with Fully Integrated Onboard System 

(Liquid Seal/Solenoid Tank-Mounted Rollover/Vent 

Valve) 

This fuel system configuration is similar to the previous 

fuel system with a fully integrated onboard system using a 

liquid seal (Fuel System No. 7) except that the necessary valve 

functions (rollover, vent) are built into one solenoid 

activated valve on the top of the fuel tank instead of on the 

fillneck. This configuration also incorporates a fill limiter, 
P.13 

and the canister is located closer to the fuel tank which 

allows the use of a smaller diameter vapor vent line from the 

fuel tank to the canister than that used in Fuel System No. 7. 

Therefore, this design is basically an enlargement of the 

current evaporative emission control system and is similar to 

the base case fuel system except for the addition of a liquid 

seal, a fill limiter, the combination solenoid vent/rollover 

valve mounted on the tank, a larger carbon canister and the 

elimination of external vapor line on the fillpipe. This 

system is shown in Figure 4a; the modifications to the base 

system are detailed in the Appendix. 

8.b Base System with Fully Integrated Onboard System 

(Liquid Seal/Mechanical Tank-Mounted Rollover/Vent 

Valve) 

This fuel system is nearly identical to Fuel System No. 8a 

except that this system uses a mechanical rollover/vent valve 

mounted on the fuel tank instead of a solenoid activated 

combination valve. This system is the same as the one shown in 

Figure 4a except that the mechanical rollover/vent valve shown 

in Figure 4b is used instead of a solenoid activated valve. 

9. Base System with Fully Integrated Onboard System 

(Mechanical Seal) 

This fuel system configuration is the same as the system 

with the fully integrated onboard system incorporating a 

fillneck mounted rollover valve (Fuel System No. 7) except that 

it has a mechanical seal. The only modifications from are Fuel 

System No. 7 the type of seal used, the inclusion of a simple 

pressure relief device, and the size of the canister. These 

are described below. Only the changes caused by the use of a 

mechanical seal need be analyzed incrementally. 

First, this fuel system design uses a mechanical type seal 

instead of a liquid seal. The mechanical type seal is 

basically an elastomeric device which forms a.close connection 

with the inserted fuel nozzle and thereby eliminates any. space 

in the fillneck opening through which vapor could escape. Such 

a mechanical seal is pictured in Figure 5. In order to prevent 

any overpressurization of the fuel tank from failure of an 

automatic nozzle shutoff mechanism or blockage of the vapor 

line to the canister, a simple pressure relief device is also 

incorporated into the fillneck area. This pressure relief 

device is a pressure-sensitive diaphragm valve which, under 

overpressurization conditions, would open an "emergency" 

passage to the atmosphere through which the pressurized vapor 

and gasoline would spill onto the pavement or some other 

location noticeable to the operator. A fillneck-mounted 

rollover/vent valve with a pressure relief device is shown in 

Figures 6 and 7 during normal vehicle operation and a refueling 

event, respectively. 
Second, since using a mechanical seal instead of a liquid 

seal on an onboard system results in lower refueling emissions, 

the carbon canister size of this system is smaller than the 

canister used in the previously described system with a liquid 

seal. The canister used in this particular fuel system is 

approximately 4 liters in capacity. It is located under the 

vehicle hood, at the location of the present evaporative 

canister. 

10. Absolute Risk Comparison 

In each case up to this point, the modifications to the 

fuel system were to be evaluated incrementally to the baseline 

vehicle fuel system. For this case, the contractor shall 

perform an analysis comparing the absolute risk of the baseline 

vehicle fuel system (Fuel System No.l) to that of the following 

vehicle fuel system modifications: (Fuel System No.'s 6, 8a, 

8b, and 9) 

III. Deliverables 

As part of this work assignment, the contractor shall 

provide the following deliverables to EPA: 

1. Detailed Work Plan 

The detailed work plan should summarize the steps the 

contactor plans to take in order to complete this work 

assignment. This document should describe the goals of the 

project, the basic risk assessment process and approach to be 

used, the ways to gather the necessary technical information on 

the fuel system designs and the likelihoods of occurrence for 

potential problems, the methods of analyzing the FMEA results, 

the proposed ranking methodology and the format of the required 

report. This detailed work plan should also include an 

estimate of the resources needed by the contractor in order to 

complete the work assignment. Approval of this work plan by 

EPA is necessary before the contractor begins the comparative 

risk assessment outlined in this work assignment. 

2. Presentation of Results 

This oral presentation to EPA should summarize the work 

performed by the contractor (up to that date) for this work 

assignment. It should explain the basic risk assessment 

approach and process taken and provide as many results to EPA 

. as possible from the risk assessments for each evaluation phase 

and fuel system configuration. 
3. Draft Report 

This report should document all the work the contractor 

performed for this work assignment. It should summarize the 

FMEAs and risk assessments for each evaluation phase and fuel 

systems configuration specified. In addition, the report 

should provide some comparison tables for and discussion of the 

relative potential risk of each evaluation phase (and one for 

the overall fuel system risk) for all the specified fuel system 

designs. These tables should rank the relative risk of each 

design on the common scale used (and referenced) by the 

contractor in the risk analyses of the base system and all the 

modifications. Any references used or judgments made must be 

documented. 

4. Final Report 

This report will summarize the comparative risk assessment 

performed for this work assignment. It will incorporate the 

suggested comments and revisions to the draft report made by 

the EPA technical work assignment monitor. 

5. Final Presentation to EPA 

This oral presentation to EPA should summarize the 

comparative risk assessment. It should explain the steps 

taken, the results found, and the comparison of potential risk 

for each specified evaluation phase and fuel system design. 

IV. Schedule of Deliverables 

Deliverable Date 

1. Detailed Work Plan 2/29/88 

2. Presentation of Results 4/10/88 

3. Draft Report 5/10/88 

4. Final Report 6/15/88 

5. Final Presentation 6/30/88 
P.16 

Appendix 

1. Base Case Vehicle/Fuel System (Fuel System No. 1) 

The following discussion is a brief description of the 

base case fuel system used in this work assignment. For 

further detail, the base vehicle, a 1986 Oldsmobile Cutlass 

Ciera with a carbureted 2.8L engine should be analyzed. 

The fuel tank filler neck (located on the side of the 

vehicle) is equipped with a plastic threaded screw type cap 

which seals the system. This cap has a long threaded area 

designed to allow any remaining fuel tank pressure to escape 

during the cap removal process. The fuel filler neck is made 

of steel and has a built-in restrictor to prevent refueling 

with leaded gasoline and a vapor/spitback deflector. A steel 

fillpipe connects the fillneck to the top of the fuel tank. 

The fuel tank (59 liter capacity) is made of steel and has a 

vertical baffle which supports the filler pipe and serves as a 

slosh baffle. A fuel tank unit is mounted in the top of the 

fuel tank with an "0" ring and locking cam. This unit contains 

an interface plate with the fuel gauge unit, fuel pickup line, 

fuel vapor vent tube, limiting orifice, and fuel filter. The 

fuel gauge unit uses a floating arm and potentiometer to sense 

the fuel level in the tank. The fuel pickup line is a steel 

tube which draws fuel from the tank to the fuel pump for 

consumption in the engine. The fuel vapor vent tube also 

attached to the fuel tank unit's interface plate, vents the 

evaporative emissions from the fuel tank to a canister for 

storage. A small limiting orifice is incorporated in the vapor 

vent tube. The limiting orifice is designed to control the 

vapor vent rate from the tank as pressure builds and to limit 

the amount of liquid which can enter the vapor line in the 

event of a vehicle rollover. Finally, a nylon fuel filter is 

attached to the end of the fuel intake tube within the tank. 

A rubber hose, attached to the fuel intake tube with hose 

clamps, connects the fuel tank to the mechanical fuel pump on 

the engine block. Another rubber hose, attached to the fuel 

vapor vent line with clamps, routes the fuel vapors from the 

tank to a small plastic tube on the vapor storage canister. 

The hard plastic canister (1.5 liter capacity) is located in 

the front of the vehicle under the hood. Evaporative emissions 

from above the float chamber in the carburetor air horn are 

also routed to the canister through a steel carburetor tube and 

rubber hose. The canister absorbs these vapors in a bed of 

activated carbon and stores them until the canister is purged 

during engine operation by air drawn through the filter at the 

bottom of the canister. As the canister is purged, the vapors 

are routed through a hose to the carburetor for consumption in 

the engine. 
P.17 

A-l 

2. Base System with Fuel Injection (Fuel System No. 6) 

The following discussion provides further detail to Fuel 

System No. 6 of the work assignment, the base case fuel system 

with fuel injection. Since this system uses port fuel 

injection instead of a carburetor to supply fuel to the engine, 

some changes to the base system are necessary. These changes 

are described below. 

First, the fuel tank unit in the fuel tank is modified so 

that it contains an interface plate with the fuel gauge unit, 

fuel pickup line, fuel pump, fuel vapor vent tube, limiting 

orifice and fuel return tube. In this design, the fuel pump, 

located within the fuel tank, is electric. In addition, the 

fuel tank unit contains a steel fuel return tube which allows 

unused fuel from the fuel injection system to be returned to 

the tank. The fuel filter used in this fuel injection system 

is located outside of the fuel tank. Fuel from the fuel pump 

is routed to the fuel filter via the fuel intake line before it 

is mixed with the intake air. 

Second, this fuel system design with fuel injection 

includes a pressure regulator to control the fuel pressure. If 

the pressure gets too high, this regulator dumps some of the 

fuel back into the fuel tank via the fuel return line, which is 

connected by hose clamps to the fuel return tube on the fuel 

tank unit. Recirculating fuel back from the engine will likely 

increase the temperature of the' fuel in the tank and thus the 

volatility (evaporation rate) of the fuel in the tank. 

Finally, the evaporative emission control system is 

modified slightly with the incorporation of fuel injection. 

With fuel injection, the evaporative emissions, from the 

carburetor will be eliminated. Therefore, this fuel system 

design does not have a vapor line connecting the carburetor 

float chamber to the canister. 

3. Base System with Fully Integrated Onboard System with 

Liquid Seal and Fillneck-Mounted Rollover/Vent Valve (Fuel 

System No. 7) 

The following discussion provides more detail to Fuel 

System No. 7 of the work assignment, the base case fuel system 

with a fully integrated onboard system using a liquid seal and 

a fillneck-mounted rollover/vent valve. With the addition of 

an onboard system, several changes are made to the base case 

fuel system. 
P.18 

A-2 

First, this configuration uses a liquid seal as a sealing 

mechanism to prohibit the vapors in the fuel tank from escaping 

to the atmosphere via the fillneck. Possible design approaches 

include a J-tube or flowing liquid seal which may also use a 

flow restricting gate. Each of these approaches creates a 

liquid trap. Various designs are shown in Figures 8 and 9. 

Second, this particular configuration adds one vapor vent 

line and enlarges a portion of the existing vapor line of the 

base fuel system. As in the present configuration, a rubber 

external vapor vent line connects the top of the fuel tank to 

the fillneck. This line is attached with hose clamps to a 

steel extension on the fuel tank and to an inlet nipple on a 

high impact plastic rollover/vent valve located at the top of 

the fillneck (which is described below). A rubber refueling 

vapor vent line is connected to the outlet nipple on the 

rollover/vent valve at the fillneck. This vapor line joins 

with the vapor vent line from the fuel tank at a "T" joint and 

routes all the fuel vapors to the carbon canister under the 

hood. The rubber vapor line between the "T" joint and the 

canister is increased in diameter from the base system in order 

to accommodate both refueling and fuel tank emissions. The 

vent line diameter is 3/8 to 1/2 inches. 

Third, this fuel system . configuration incorporates a 

rollover valve. A plastic nozzle-actuated rollover/vent valve 

is inserted in the fillneck area. This valve is integral to 

the fillneck and. located near the leaded fuel restrictor. 

Diagrams of the fillneck-mounted rollover/vent valves are shown 

in Figures 10 and 11. During refueling, the valve is opened by 

the insertion of a fuel nozzle. With the valve open, a clear 

passage through the vent line is available to allow for the 

routing of refueling vapors to the charcoal canister. Other 

than during refueling, the valve remains closed and eliminates 

the potential for fuel leakage through the refueling vent line 

during a vehicle accident. 

Finally, the charcoal canister of this integrated fuel 

system is larger than the base system's canister in order to 

accommodate the captured refueling emissions. For this 

particular fuel system design, the size of the canister is 

approximately 4.5 liters. It is located under the vehicle 

hood, at the location of the present evaporative canister. 
P.19 

A-3 

4. Base System with Fully Integrated Onboard System with 

Liquid Seal and Solenoid Tank-Mounted Rollover/Vent Valve 

(Fuel System No. 8a) 

The following discussion provides greater detail to Fuel 

System No. 8a of the work assignment, the base system with a 

fully integrated onboard system using a liquid seal and a 

solenoid tank-mounted rollover/vent valve. This configuration 

is similar to the base case fuel system except for a few 

changes, which are discussed below. 

First, this fuel system design utilizes a liquid seal as 

described in the Appendix for Fuel System No. 7. 

Second, this fuel system configuration incorporates a fill 

limiter in the top of the fuel tank to prevent liquid fuel from 

entering the vapor line when the tank is full. The fill 

limiter is a ball-in-cage float valve. (Figure 12) As the tank 

becomes full, the float rises in the fill limiter and closes 

off the refueling vent line. 

Third, this configuration employs a vapor vent/rollover 

valve with a vapor/liquid separator and limiting orifice. The 

vapor/liquid separator is mounted in line, above the fill 

limiter. This separator is made of plastic and stainless steel 

wire mesh which forces any entrained liquid droplets or 

condensed vapors to return to the fuel tank instead of going to 

the canister. Following the vapor/liquid separator is a 

solenoid activated rollover valve with a limiting orifice. 

When, refueling begins, a microswitch activated by the nozzle 

insertion activates the solenoid which opens the vapor vent 

line to the carbon canister. After the refueling event, the 

fuel nozzle is removed, which deactivates the microswitch and 

the solenoid closes the vent valve. This will prevent fuel 

leakage in the event of a vehicle rollover or other fuel system 

failure. See Figures 13 and 14. This valve is mounted in the 

top of the fuel tank. 

Fourth, the vapor vent line to the canister is roughly the 

same diameter as that used in the base case fuel system. It is 

possible to use roughly the same size diameter in this system 

to accommodate the refueling vapors since the canister is 

located only a few feet from the fuel tank. The vent line 

diameter is 1/4 inch to 3/8 inch. 

Fifth, since it is no longer needed, the external vent 

line on the fillpipe is eliminated. 
A-4 

Finally, the canister of this fuel system will be larger 

than that of the base system so that it can store the captured 

refueling emissions. With this liquid seal onboard design, the 

canister is approximately 4.5 liters in capacity. The canister 

is located under the body of the vehicle at a location near the 

fuel tank. 

5. Base System with Fully Integrated Onboard System 

with Liquid Seal and Mechanical Tank-Mounted 

Rollover/Vent Valve (Fuel System No. 8b) 

The following discussion provides greater detail to Fuel 

System No. 8b of the work assignment. This configuration is 

identical to Fuel System No. 8a except that this system uses a 

mechanical rollover/vent valve instead of a solenoid valve. 

The mechanical valve incorporates the fill limiting, vapor 

metering, liquid/vapor separating, rollover, and vent functions 

into one valve. It is shown in Figure 4b. 
Fiqure 1 

1986 Oldsmobile Cutlass Ciera Fuel Tank and Fillpipe Configuration 

Nozzle 

Spout 

Fuel Sending Unit 

and Vent Orifice 
P.22 

Figure 2a 

/?<o yy?y:0 />A.O6 
Figure 2b 

Partially Submerged Fillpipe 

tile r ? i ? 
P.24 

Figure 2c 

CRC-22 

1985 AMC 

Jeep Cherokee 

Driver's Side Front 

• 

B-23 
-NOZZLE ACTUATED 

ROLLOVER/VENT VALVE 

PRESSURE/VACUUM 

RELIEF CAP 

Figur e 3 

Integrate d Evaporative/Refuelin g Syste m 

Fillnec k Mounte d Valve s 

Fron t Mounte d Caniste r 

J-Tub e Sea l 

r 3/8-1/2" DIA 

8 ' LONG 

05" DIA. LIMITING 

ORIFICE 

FLOAT/ROLLOVER 

VALVE 

7

 u J-TUBE 

'—np. 

J-TUBE SEAL 

DESIGNED SLOW LEAK 

31 C T 1/4-3/3" DIA 

2 ' LONG 

A . 5 LITER 

CARBON 

CANISTER 

15.6 GALLON FUEL TANK 

PURGE 

VALVE 

i t-ui 

I^VA: 

TO PURGE 

INDUCTION 

POINT 

Not To Scale 
PRESSURE/VACULM 

RELIEF CAP 

Figur e 4a 

ALTERNATIVE INTEGRATED EVAPORATIVE/REFUELING SYSTEM 

TANK MOUNTED VALVES 

REAR MOUNTED CANISTER 

J-TUBE SEAL 

SOLENOID 

ACTUATED VENT/ROIJOVER 

VALVE, LIMITING ORIFICE 

6. LIQUID/VAPOR SEPARATOR 

1/4-3/8" DIA 

3 ' LONG 

Z

r

 ^-J-TUBE SFAL 

CONTROIIED IEAK 

1 5 • 6 f-AIJjON FUEL TANK 

1/4-3/8" DIA 

7' LONG 

4 • 5 LITER 

CANISTER 

PURGE 

VALVE 

i 

UJ 

I 

-f f—yH— 

TO PURGE 

INDUCTION 

POINT 

N o t To Scal e 
P.27 

DO UJ 

a 

D 

O LL 
P.28 

Description of Figure 4B 

The schematic is a cut away of the valve in its normal 

operating mode (refueling and evaporative). Additional modes 

of operation are as follows: 

1) Shut-off: Once the liquid level in the tank reaches 

a designed level, the buoyancy of the float, due to 

the spring, causes the float to rise, thus closing 

off the .325" orifice. At this point tank back 

pressure will activate the automatic shut off fill 

nozzle. The .050" orifice still provides venting 

for evaporative emissions. 

2) Roll-over: Once the valve is rotated 60° from it's 

normal vertical position, the float rises and shuts 

off the .325" orifice. The small .050" orifice 

limits the fuel spill due to it's small diameter. 
Figur e 5 

Mechanical Seal 

P.29 

MOOtfCATTONS 

ROTARY SEAL 

1W0OOR 

L£AO RESTRJCTOR 

FILL PIPE MOOIFICATICNS 

ROTARY SEAL 

ROTAPY 

T3APD00* 

LEAORESTOCTOfl 
Figure 6 

PiUneck-Mounted Rollover/Vent Valve for Mechanical Seals 

with Pressure Relief Valve 

(During Normal Vehicle Operation) 

VOCAMISlin 

1K1UIO SIOP 

IHUIOf f WUVt 

GAS CAP 

- OVERT ML 

MtMtF WUVt 

tEAOtOFUCL 

OCflECIOR 
Figure 7 

Fillneck-Mounted Rollover/Vent Valve for Mechanical Seals 

with Pressure Relief Valve 

(During Refueling Event) 

IO CAMISIER -

I KJUIO SIOP 

If AULU *Uf L 

OtfLtCIOH 

SMUI Off 

WALVL 

VAPOR x 

fROM 

OVERFILL 

RCLKF VALVE 

I 

CO 
P.32 

Figure 8 

Flow Resistance Gate Assembly 

Spring/Hinge Assembly 

Drain/Pressure 

Relief Notch 

i/8 in. Dia. 

Fillpipe 

The flow resistance gate is attached to the fuel tank at 

the bottom of the fillpipe. The spring constant of the gate 

provides enough flow resistance to cause the liquid seal during 

refueling. A notch at the bottom of the gate allows fuel to 

drain from the fillpipe after refueling and provides pressure 

relief for the fuel tank. The gate is closed at all times 

other than during refueling. This provides rollover protection 

for the fillpipe. 
P.33 

Figure 9 

J-Tube Licruid Seal 

J-TUBE 

TO CANISTER 

A liquid seal can be formed during refueling by extending 

the fillpipe into the fuel tank and forming the end into a "J" 

shape. A liquid head forms in the bottom of the "J" and 

prevents vapors from travelling up the fillpipe during 

refueling. A small drain hole is located at the bottom of the 

"J" which allows the liquid head to drain from the fillpipe 

after the refueling event. 
Figur e 10 

Fillneck-Mounte d Rollover/Ven t Valv e fo r Liqui d Seals 

(During Normal Vehicl e Operation ) 

IO CAMJSItR - SHU I Off VALVE 

GAS CAP 

LEAOEOEOtt 
Figure 11 

Fillneck-Mounted Rollover/Vent Valve for Liquid Seals 

(During Refueling Event) 

SHUIOIt 

IO CAMISIER -

VAPOR 

ffROM 
P.36 

SJ 

CN CJ 

rA 4J •H OJ E U -H 3 J 0* •H rH Cu rH •H 

I 

^ 

^ 

3 
CA? 

ACJWATOK 

TO £AKJ U IST^ K 

(Jx)- SOLENOID VALVe 

.050" BYPA55 

BALU-IKJ-^AG, ^ 

KJO SCAL g 

FIGURE 13 SCHEMATIC OF POTENTIAL ONBOARD VAPOR RECOVERY SYSTEM 

Afi MUELLER ASSOCIATES. INC. 

1401 S. CDQEWOOD •TRBET 

BALTIMORE, MARYLAND 21227 

JANUARY 91 , !•• » 
0.050 hioue 

FI CURE 14 SOLENOID-ACTUATED BUTTERFLY VALVE 

\^Q SCALE 

KB MUELLER ASSOCIATES. INC. 

140 1 8 . EDOEWOOD STREET 

BALTIMORE. MARYLAND 2122 7 

JANUAR Y 91 . 1BB S 
£-- V" 

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P.40 

SECTION 6C 

FUEL SYSTEM 

ENGINE FUEL 

ALL NEW GENERAL MOTORS VEHICLES ARE 

CERTIFIED BY THE UNITED STATES 

ENVIRONMENTAL PROTECTION AGENCY AS 

CONFORMING TO THE REQUIREMENTS OF THE 

REGULATIONS FOR THE CONTROL OF AIR 

POLLUTION FROM NEW MOTOR VEHICLES. THIS 

CERTIFICATION IS CONTINGENT ON CERTAIN 

BEING SET TO FACTORY 

IN MOST CASES, THESE 

POINTS EITHER HAVE BEEN 

SEALED AND/OR MADE 

INACCESSIBLE TO PREVENT INDISCRIMINATE OR 

ROUTINE ADJUSTMENT IN THE FIELD. FOR THIS 

REASON, THE FACTORY PROCEDURE FOR 

TEMPORARILY REMOVING PLUGS, CAPS, ETC., FOR 

PURPOSES OF SERVICING THE PRODUCT MUST BE 

STRICTLY FOLLOWED AND, WHEREVER 

PRACTICAL RETURNED TO THE ORIGINAL INTENT 

OFTHE DESIGN. 

FUEL SYSTEM 6C-1 

ADJUSTMENTS 

STANDARDS. 

ADJUSTMENT 

PERMANENTLY 

CONTENTS 

GENERAL DESCRIPTION AC-1.2 

pjsi System Pressure Relief 6C-2 

i"uel Filters 6C-2 

Fuel Tank 6C-2 

Fuel Filler Neck 6C-3 

Fuel Tank Filler Cap 6C-3 

Fue! Pump 

ML (VIN X) 6C-3 

Eiectric In-Tank 6C-3 

Fuel Pump Relay' 6C-3 

Mjitiport or Sequential Fuel Injection 6C-3 

Fuel and Vapor Pipes 6C-5 

MFPI.SFI Fuel Pipes 6C-5 

Fue! Line "0 " Rings 6C-5 

Fuji Return Hose Restrictor - 2.8L 

iVIN X) 6C-5 

On-Car Service 

Fuel Filter Replacement ..- 6C-5.6 

Fuel Pump Testing 6C-6-8 

GENERAL DESCRIPTION 

^V'hen working on the fuel >ystem, there are 

*

v

eral things to keep in mind. 

• Any time fuel system is being worked on, 

disconnect the negative battery cable 

except for those tests where battery 

voltage is required. 

• Always keep a dry chemical (Class B) fire 

extinguisher near the work area. 

• Always use a back-p wrench when loosening or 

tightening a screw couple fitting. 

The torque on a screw fittina is 35 N-m (26 lbs. 

ft.). 

Fue! Pump Replacement 6C-8.9 

Draining Fuel Tank 6C-9 

Fuel Gage Tank (Sending) Unit 6C-10 

Remral of Tank and Tank (Sending) 

I'm- 6C-I0. 

Fuel System Cleaning 6C-12 

Fuel Tank Purging 6C-12 

Fuel Tank Leak Test 6C-12 

Fuel. Fuel Return and Emission 

Pipe or Hose Repair or 

Reolacement 6C-12 

MPFI SFI Fuel Pipe Replacement 6C-I3 

Accelerator Controls 6C-13 

Accelerator Pedal and Cable 6C-14 

E2SE Carburetor Section 6C 

Throttle Body Injection Section 61 

Multi-Port Fuel Injection Section 61 

Sequential Fuel Injection Section 61 

Two types of fuel pipes are used: 

1. Standard flared pipe used on all carburet 

systems. 

2. Pipe used on all fuel injection systems h 

fittings that require the use of an "O" Rir 

The two pipe systems are n 

interchangeable. Replace all pipe with t 

same pipe and fittings that were removei 

All fuel pipe must meet the GM Specificati 

124-M or its equivalent. 

All fuel hose must meet GM Specificati 

61b3-M or its equivalent. 

Do not replace fuel pipe with fuel hose. 
P.41 

6C-2 FUEL SYSTEM 

-lilt: 

• On Fuel Injection systems, always relieve the line 

pressure before servicing any fuel system 

components. 

• Do not do any repairs on the fuel system until you 

have read the copy and checked the illustrations 

relating to that repair. 

• Adhere to all Notices and Cautions. 

FUEL SYSTEM PRESSURE RELIEF 

All Fuel Injected Engines 

CAUTION: To reduce the risk of fire 

and personal injury, it is necessary to 

relieve the fuel system pressure 

before servicing fuel system 

components. To do this: 

• Remove "fuel pump" fuse from fuse 

block in passenger compartment or from 

the underhood fuse holder with the 2.8L 

engine (VIN W), Fig. 1 or 2. 

^4 

t 

1. 

2. 

3. 

4. 

5. 

6. 

7. 

3. 

9. 

10. 

11. 

12. 

13. 

14. 

15. 

0 ra „ SL- : 

**>** <o. (JJ -t=z_~=; 

<V~" *Rrvv ^F^&LsZy— 

• 

T4j 

••f-^L— W/. <^T**fitz%x,i 

r • 

y>* ^ «E"*" • IMJ 

o 3N 

1.9 N-m (16 LBS. IN.. 

4.7 Nv n 142 LBS. IN.) 

2.3 Nv n (24 LBS. IN.) 

A.C ACCUMULATOR 

PL EL PUMP RELAY 

CLIP 

MAP SENSOR RELAY 

MAP FUSE 

FORWARD LAMP HARNESS 

CRUISE CONTROL HARNESS 

BATTERY CABLE 

COOLING FAN RELAY 

TCC CONNECTOR 

H3 

./ \ Vv 

j/%t \ 

lOL -

NEUTRAL START & BACKUP LAMP SWlTr-

<*U.ELPUMP FUSE 

G 

^ X ^ 

:,-< ^ r 

r Y 

~ / / 

CON". "iCT0? 

aias-sD i ai 

Fig. 1 A Series. VIN W Fuei Pump Fuse & Selay 

• Crank engine - engine will start ;lnrt 

until fuel supply remaining in fu«| j! ^ 

is consumed. Engage starter f0r 7* 

seconds to assure relief of any rennai '* 

pressure.

 n,i*| 

• With ignition "OFF", replace fuel n. 

fuse.

 Pl % 

Unless this procedure is followed bef 

servicing fuel pipes or connections, f?!9 

spray could occur. ' *' 

When repair to the fuel system has b 

completed, start engine and check all connections th^ 

were loosened for possible leaks.

 at 

Fuel System 

All engines are designed to use only unlead* 

gasoline. Unleaded gasoline must be used'for pr0r^. 

emission control system operation. Its use will alf 

minimize spark plug fouling and extend engine oil |if.° 

Using leaded gasoline can damage the emission control 

system and could result in loss of emission warrant 

coverage. 

All cars are equipped with an Evaporative 

Emission System. The purpose of the system is ;c 

minimize the escape of fuel vapors to the atmosphere 

Information on this svstem will be found in Seeing 

6E1. 6E2or 6E3. 

FUEL FILTER 

The 2.8L ("-'IN X) has a filter located in :he 

carburetor fuel '.et. The fuel filter element is ;• 

pleated paper. Eiv'.ent is placed in the inlet fitting Wiethe gasket surface utward. A spring holds the elemem 

outward, sealing by compressing a gasket surface 

against the inlet :' :ing. 

On cars with Fuel Injection an in-line filter ;$ 

used. The filter is located at the rear of car. near the 

fuel tank on all but the C & H Series. 

The C Sc H Scries uses an in-line filter mountec 

on the rear body raii. 

In-line filter ..se an "0 " ring where the fuei pipes 

screw into the fue: filter. 

If an elemen: ^ouid e^er become plugged, the 

engine will stop. An engine' stoppage caused by i 

plugged filter element will be preceded by a hesitation 

or sluggish operation. 

Other Filters or Strainers 

A woven plastic filter is located on the lower er.' 

of the fuel pick-up pipe in the fuel tank. This fii;<* 

prevents dirt from entering the fuel . .c and aisc nop 

water unless the filter becomes completely submerged 

in water. This niter is self cleaning and norma:;' 

requires no maintenance. Fuel stoppage at this poir.: 

indicates that the fuel tank contains an abnormal 

amount of sediment or water; the tank should therefore 

be removed and thoroughly cleaned. Also see "Fue: 

System Cleaning." 

FUEL TANK 

A vertical baffle is installed in the tank.to support 

the filler tube and *o serve as a slosh baffle. 

tl 

d 

t 

f 

r 
FUEL SYSTEM 6C-3 

P.42 1 

cuel P'll,8r 

r help prevent refueling with leaded gasoline, 

filler neck on has a built-in restrictor and 

The opening in the restrictor will only allow -h« 

fuel 

J

e,leCt°ijer unleaded gas nozzle spout which must be 

<\MSI-** erted to bypass the deflector. Attempted 

•

u

^ I-'

 2 with a leaded gas nozzle or failure to fully 

retu<;

 the unleaded gas nozzle will result in gasoline 

in'iflin2 back out of the filler neck. 

nlasfin'e 

Ful, Tank Filler Cap 

The fuel tank filler neck is equipped with a screw 

_ The threaded part ofthe cap requires several 

^-"•-ounterclockwise t 0 remoV e . The long threaded 

jrn:>*as designed to allow any. remaining fuel tank 

i!ii

.u:e to escape during the cap removal operation, 

^built-in torque limiting device prevents 

"* ...ughtening. To install, turn the cap clockwise until 

^licking noise is heard. This signals that the correct 

iVraue has been reached and the cap is fully seated. 

NOTICE: If a fuel filler cap requires replacment, 

onlv a cap with the same features should be used. 

Failure to use the correct cap can result in a serious 

malfunction of the system.. 

Fuel Filler Door Lock 

Information on the fuel filler door lock can be 

found in the Body Service Manual. 

FUEL PUMP 

2.8L (VIN X) 

The fuel pump rocker arm is held in constant 

engagement with the eccentric on the camshaft by the 

rxker arm spring. As the end of the push rod. which 

- :n .ontact with the eccentric moves upward, the fuel 

:r.K pulls the fuel diaphragm downward. The action of 

:'•£ diaphragm enlarges the fuel chamber drawing fuel 

•'rem the tank through the inlet valve and into the fuel 

.•lumber. 

The pump delivers fuel to the carburetor only 

*hen the pressure in the oulet line is less than the 

rressure maintained by the diaphragm spring. 

Therefore when more fuel is required, the spring will 

;*pand to move the diaphragm upward to force fuel 

past the outlet valve. When less fuel is required, the 

pump builds up pressure in the fuel chamber until the 

diaphragm spring is again compressed. The diaphragm 

-•'il then remain stationary until more fuel is required. 

EXCEPT 2.8L (VIN X) 

The electric fuel pump used on these engines is 

attached to the bottom of the fuel sending unit. To 

-"-•nirol fuel pump operation, a fuel pump relay is used. 

When the ignition switch is turned to "RUN" 

?°Sltion. the fuel pump relay activates the electric fuel 

?

u

*np for 1.5 to 2.0 seconds to prime the injector(s). If 

^

e

 ECM does not receive reference pulses from the 

;

lstnbutor/crankshaft sensor after this time, the ECM 

^gnals the relay to turn off the fuel pump. The relay 

111 0nce again activate the fuel pump when the ECM 

receives distributor/crankshaft sensor reference pulses. 

Electrical Diagnosis 

For electrical diagnosis see: 

1.8L, 2.0L and 2.5L = Section 6E2 and Section 

8A. page 20-0 

2.8L (VIN W), 3.0L and 3.8L = Section 6E3 and 

Section 8A, page 22-0 

Electrical Diagnosis 

For electrical diagnosis see Section 6E3 and 8A, 

page 20-0. 

FUEL PUMP RELAY 

See Figs. 1 through 9 for location and mounting 

of the fuel pump relay. 

5B6CB7 

Fig. 2 J Series Fuel Pump Relay - 2.0L & 2.8L 

RT FRONT 

SB6C79 

Fig. 3 J Series Fuel Pump Relay - 1.8L w/ o AC 

FUEL INJECTION - 2.8L (VIN W), 3.0L AND 3.8L 

Fuel is recirculated through a rail continually 

while the engine is running. This removes air and 

vapors from the fuel as well as keeping the fuel cool 

during hot weather operations. 
6C4 FUEL SYSTEM 

1 FUEL PUMP RELAY 

T " A/C RELAY 

T ~ RIGHT FENDER 

Fig. 4 J Series Fuel Pump Relay - 1.8L with AC 

1 FUEL PUMP RELAY 

~ A/C RELAY 

FAN 

Fig. 5 N Series Fuel Pump Relay - 2.5L 

Fig. 6 N Series Fuel Pump Relay - 3 OL 

The fuel pressure regulator that is mounted on 

the fuel rail, maintains a variable pressure across the 

injectors. It is accomplished by controlling the amount 

of fuel that is recirculated back to the fuel tank based 

on engine demand. 

The pressure regulator also utilizes an "0 " ring 

for attachment. The "O" ring used is the same one that 

is used for the injectors. 

A Pulsator Dampener Assembly is installed on 

the fuel tank sending unit. It is used to reduce fuel 

pump noise (Fig. 22). 

Fig. 7 Fuel Pump Relay - 2.5L A Series 

G40045 6Q.> 

Fig. 8 Fuel PL.~D Relay - 3.8L A Series 

5B6C71 . 

Fig. 9 Fuel Pump Reiay - 3.0 and 3.8L C& H Series 
P.44 

FUEL SYSTEM 6C-5 

"*-* 

V, 

The 3.0L engine used in the H Series also utilizes 

mUlator that is located in the fuel feed line near 

inaC.owl area (Fig. 10). It is used to dampen the 

tttf

 c

. t jj a t is caused by the pressurized fuel and the 

p53 i of the injectors. 

1. FUEL FEED PIPE 

2. ACCUMULATOR (PART OF ITEM 1) -3.0LONLY 

(MAINTAIN HORIZONTAL POSITION OF DAMPENERACCUMULATOR ASSEMBLY 

3. FUEL RETURN PIPE 

4. FUEL FEED HOSE 

5. FUEL RETURN HOSE 

6. "0"RING SEALS 

*. 34 Nin (25 LBS. FT.) 

3. USE BACK-UP WRENCH HERE 

9. L.H. ENGINE COMPARTMENT FRAME RAIL 

G34605 5C H 

:

-g 10 3.0L Fuel Accumulator/Dampener ana Pipes - H 

Series 

FUEL AND VAPOR PIPES 

The fuel feed and return pipes extend from the 

'-el gage sending unit to the engine compartment. The 

-•pes are secured to the underbody with clip and screw 

-issemblies. Both fuel feed pipes must be properly 

routed and retained, and should be inspected 

•Kcasionally for leaks, kinks or dents. If evidence of 

-in is found in the throttle body unit or fuel filter 

Junng disassembly, the pipe should be disconnected 

•ind blown out. Check the fuel strainer on fuel gage 

ending unit for damage or omission. 

The vapor pipe extends from the fuel gage sender 

•°

 [he canister. However, it does not follow the same 

route

 as the fuel feed pipe. 

If replacement of a fuel feed pipe or vapor pipe 

^quired, use brazed seamless steel tubing meeting 

^M Specification 124M, or its equivalent. 

Under no conditions use copper or aluminum 

tubing to replace steel tubing. Those materials do not 

have satisfactory durability to withstand normal 

vehicle vibrations and corrosion. 

NOTICE: The hoses are specially manufactured 

and if replacement becomes necessary, it is 

important to use only the service replacement 

hoses identified with the words

 ,,Fluoroelastomer" 

on them. Hoses not so marked could cause early 

failure or failure to meet emission standard. 

MPFI/SFI FUEL PIPES 

Due to the fact that the fuel pipes/hoses are 

under high pressure on Engine Code B, L. W and 3, 

this system requires special consideration for service. 

All fuel feed and return line attachments in the 

system are screw fittings type. Always use a back-up 

wrench when loosening or tightening the fittings. 

Screw fittings used on these two systems utilize "O" 

rings for the fuel feed and return pipes and the two sizes 

of "0 " rings are not interchangeable. Any time that the 

fuel or return pipes are disconnected, inspect the "O" 

rings for cuts or other type of damage and replace as 

necessary. The flare used on these fuel pipes is not 

compatible with the flare used on other fuel pipes. 

FUEL LINE "0" RINGS 

The fuel line "O" Rings used are made of 

Viton J. They are brown in color. Viton? is less 

affected th. rubber by the additives used in manyfuels and th .efore rubber should not be substituted. 

FUEL RETURN HOSE RESTRICTOR ASSEMBLY 

-2.8L(VIN X) 

Figs. 11 and 12 

A restrictor assembly is installed in the fuel 

return hose, above the transaxle. This brass restrictor 

has a 1.25 m:- orifice that restricts fue! return to the 

fuel tank i Fie. 11). The purpose of this restrictor is to 

reduce fuei rump noise, especiallv when the engine is 

cold. 

ON-CAR SERVICE 

2.8L (VIN X) ENGINE FUEL FILTER 

REPLACEMENT 

Fig. 13 

l. Disco nn ct fuel line connection at fuel inlet filter 

nut. 

2. Remove fuel inlet filter nut from carburetor. 

3. Remove filter and spring. 

4. If removed, install check valve in fuel inlet filter. 

The fuel inlet check valve must be installed in the 

filter to meet Motor Vehicle Safety Standards (M.V.S. 

S.) for roll-over. New service replacement filter must 

include the check valve. 

5. Install fuel inlet filter spring, filter, and check 

valve assembly in carburetor. Check valve end of 

filter faces toward fuel line. Ribs on closed end of 

filter element prevent filter from being installed 

incorrectly unless forced. 
P.45 

I 

•>h 

•Wli|»-

!

"»l*t 

6C-6 FUEL SYSTEM 

1.25 mm 

G3A3438C A 

Fig. 11 Fuel Return Hose Restrictor - 2.31 (VIN X) 

1. RETURN HOSE RESTRICTOR - INSTALL 

WITH •TANK" MARKING TO REAR OF CAR 

2. FUEL RETURN HOSE 

3. FUEL FEED HOSE 

TIGHTEN CLAMPS ON ALL HOSES TO ' 55 N • - (1<» L8S. IN.) 

383121863 

Fig. 1 2 Fuel Return Hose Restnct c 'retaliation - 2.3L 

(VIN X) 

SPRING 

FILTER (WITH 

\ CHECK VALVE) 

GASKET 

FUEL INLET 

NUT 

100'27 

Fig. 1 3 2.8L (VIN X) Engme F-jei filter 

6. Install fuel inlet filter spring, niter, and install nut 

in carburetor. Tighten nut to bl N • m (46 lbs. ft.). 

7. Install fuel line and tighten connection. 

8. Start engine and check for leaks. 

ENGINE FUEL FILTER REPLACEMENT - 1 8 2n 

2.5, 2.8L (VIN W), ' °' 

Before replacing a fuel filter on cars wi** 

these engines, it is necessary to relieve Wi 

system pressure, see "Fuel System Pressure 

Relief." * 

On all but C and H Series, the fuel filter is located 

under the rear of the car. See Fig. 14 or 15. The C & 

H Series fuel filter is located under the car. in front of 

the left rear tire and wheel assembly. See Fig. 16. 

B 

2. 

3. 

B 

Remove or Disconnect 

Hoist car, see Section OA. 

CAUTION: To help avoid personal 

injury when a vehicle is on a hoist 

provide additional support • for the 

vehicle at the opposite end from 

which components are being 

removed. This will reduce the 

possibility of the vehicle falling off of 

the hoist. 

Fuel lines from filter 

Filter from car 

Install or Connect 

2. 

Filter in position loosely 

U- z new "0" ring seals, instal 

int. "he filter. 

the fuel lines 

9 Important 

• Uses back-up wrench to prevent filter. "0" 

ring or fuel line damage. 

• Tighten line fittings to specification. 

Secure filter to car. 

Louer car. 

9 Inspect 

• Star: engine and inspect for leak. 

FUEL SYSTEM PRESSURE TEST 

Thh rest must be performed when diagnosing the 

fuel system. 

Before working on the fuel system on cars 

with EFI PFI, it is necessary to relieve fuel system 

pressure, see "Fuel System Pressure Relief." 

Pressure Test - 1.8, 2.0L AND 2.5L 

Figs. 17, 18 or 19 

1. Remove air cleaner and plug vacuum port on 

throttle body unit. 

2. Disconnect the engine fuel feed hose from the fuel 

feed pipe. 

3. J Series with 2.0L engine (VIN P), hoist the car, 

see Section OA. 

CAUTION: To help avoid personal 

injury when a vehicle is on a hoist. 
P.46 

-ated 

•ntof 

lines 

. "0' 

ne the 

n cars 

ystem 

;f." 

ort on 

he fuel 

he caral 

st, 

FUEL SYSTEM 6C-7 

£_ FUELTAN K 

=H VAPOR HOSE 

-TT L FILTER _LFUE L 

• '"* RETURN 

y f\jn^E0 HOSE — 

"- HOS£ 

. RgAf , BRAKE CROSSOVER PIPE 

"- 0N m(22FT.LBS. ) 

. , BACKUP WRENCH AT AL L SCREW COUPLE 

3 '^/TriON S ALSO MAKE SURE A GOOD 0 ' 

""TNG IS INSTALLED AT THESE LOCATIONS 

•8RICATE HOSE ENDS FOR INSTALLATION 

• " 586C66 

Pig. 14 J and N Series Fuel Filter 

v ^ 

-C5E 

_ 

J 

i 

5 

6 

" C 

FUE 

r-\ 

^UE 

FUE 

.•• - . 

_ r''_ * 

RING 

T

i > 

. SE'"' 

••ts c 

ER 

K 

L C M 

:;g. 15 A Series Fuel Filter (Exc. 2 3 l VIN Xi 

provide additional support for the 

vehicle at the opposite end from 

which components are being 

"amoved. This will reduce the 

Possibility of the vehicle falling off of 

the hoist. 

'nstall pipe and adapter assemble J-2%53-85 

onto gage assemblv J-29553 with J-_%5.VJ: 

adapter. 

D

'sconnect front fuel feed hose from the fuel pipe 

°n the bodv. 

nn ^£ 

\ •& ?. •%#% 

_ _ FUEldlTE R 

T " FUEL = EEDKNE 

3 GOING 

30 NJ ~r 

2? FT .3S 

A USE SACK UP WRENCH 

AT THIS LOCATION 

3 ALSO MAKE SbPE ORING iS ON 

PIPE PRIOR TO'NSTALLATIO N 

i C ; 3RAKE PIPE 

Fig. 16 C & H Series Fuel Filter 

FUEL FEEFUEL RE " 

" 0 " RING 

3C ,Mn- •; . 

uSE 3ACA * ALL " 

LOCAT;:\ : 

SURE A GO : 

IS INSTAL- -

.VRENCH 

:,', COUPLE 

-'-SO V1AKE 

0 0' RING 

3 AT AL'_ 

"SE LOC--:CN S 

A 3 

:i86C65 

;

g. • 7 J Ser -s Engine Fuei Hoses 4 Pipes - 1 3L 

38 '1072327 

ig. 1 3 J Ser es Engine Fuel Hoses & P'pe-5 - 2.0L 

Install ga^e assembly between the fuei feed hose 

and pipe. 

Start the engine and check for leaks. 

Observe ihe fuel pressure reading. It should be o2 

to 90 kP.i 19 to 13 psi). If not. refer to EFI 

DiasnoM> Chart A-5 in Section bE2. 
6C-8 FUEL SYSTEM 

•> 

' I ! 

3 FUEL RETURN HOSE 

" A " 30 N m (22 FT. LBS.! 

8 ' USE BACK UP WRENCH AT AL L 

SCREW COUPLE LOCATIONS, ALSO 

MAKE SURE A GOOD ' 0 " RING IS 

INSTALLED AT ALL 

THESE LOCATIONS 

5B6C5 S 

Fig. 19 Engine Fuel Hoses & Pipes - 2.5L 

9. Depressurize the fuel system and remove the gage 

with adapters. 

10. Using a new "0 " Ring, reconnect the fuel feed 

hose to the pipe and tighten the fitting to a torque 

of 35 N-m(26 1bs. ft.). 

11. Lower the car. Start the engine and check for fuel 

leaks. 

12. Remove the plug covering the vacuum port on 

the throttle body and rnstall the air cleaner. 

Pressure Test-2.8L (VIN X) 

1. Disconnect the fuel line at the carburetor. 

2. Install a low pressure gage onto the line. 

3. Start the engine. 

4. Fuel pump pressure should be 37.9 to 44.3 krt 

(5.5 to 6.5 psi). 

5. -If pressure is less, check for restrictions in the 

tank unit filter, pipes or he- s. 

6. Reconnect the fuel line. 

NOTICE: Hold the carburetor fuel iniet nut while 

tightening the fuel line fitting to prevent 

carburetor damage. 

Vacuum Test-2.8L (VIN X) 

1. Disconnect inlet hose at pump and connect a 

vacuum gage. Crank or run engine until 

maximum vacuum is reached. If less than 50.6 

kPa (15 inches), replace pump. If vacuum reading 

is 50.6 kPa (15 inches) or more, go to Step 2. 

2. Check fuel lines and hoses for splits, leaks or 

kinks by disconnecting each section o( Ime and 

3. 

connecting a vacuum gage. Crank or run th 

engine until vacuum gage peaks. Vacuum shn i 

be at least 50.6 (15 inches). If less, repair repi

 d 

the malfunctioning line or hose.

 ac<: 

If fuel lines and pump check OK, remove tanL 

strainer and clean fuel tank. unit f , replace 

necessary. 

Flow Test - 1.8, 2.0, 2.5 and 2.8L (VIN X) 

1. Connect a hose from the carburetor or TBI fUei 

feed line to a suitable unbreakable container. 

2. For the 1.8, 2.0 and 2.5L: Apply battery volta»« 

to terminal "G" of the ALCL (see Section 6E2) 

If the fuel pump does not operate, see Section 6E" 

or 8A. page 20-0 or 22-0. For the 2.8L (VIN \r 

Start the engine. 

3. Fuel pump should supply 1/2 liter (1/2 pint) or 

more in 15 seconds. 

4. If flow is less than this minimum, check for fUej 

restrictions. 

Fuel System Pressure Test - 2.8L (VIN W), 3.01 

and 3.8L 

Fuel system diagnosis on this engine is in Section 

6E3, Chart A-7. If a symptom of extended crankm* 

time is encountered on these engines and the diagnosis 

in Section 6E3 does not uncover the problem, do the 

following: 

1. Remove pump and sender assembly from the fue: 

tank, see "R. -.oval of Tank and Tank Unit". 

2. With tank un:: filter still attached, submerge the 

assembly in clean water to completely cover the 

pump and pu -ator. 

3. Apply reguL:.-d'air pressure not exceeding 13j 

kPa (20 psn to the fuel outlet pipe of the 

assembly. 

4. Watch for air escaping from around the pulsator. 

the pump coupling hose or the bottom of the fue: 

pump to determine which component requires 

replacement. 

NOTICE: Do not leave the pump and sencer 

assembly submerged in water for extended pence* 

of time and blow dry immediately upon removal 

Failure to do :his will result in damage to (he 

assembly. 

FUEL PUMP REPLACEMENT - 2.8L (VIN X) 

Fig. 20 

«•• • 

1. 

2. 

3. 

4. 

Remove or Disconnect 

Fuel inlet hose from pump 

Heat shield 

Fuel outlet pipe and vapor return hose 

Two (2) 1/2 inch hex head bolts or nuts, using • 

3/8 inch deep drive socket and a ratche: hanu'; 

5. Fuel pump 

p4-l Install or Connect 

1. Fuel pump with new gasket 
P.48 

FUEL SYSTEM 6C-9 

• FUE L FEED PIPE •• 3 FUELPUMP 

=? FuEL RETURN PIPE ~AT 25 Nm •! '.3 FT LBS) 

=-=, £ BACKUP WRENCH AT ALL SCREW 

1 - rOUPLE LOCATIONS MAKE SURE A GOOD 

• Q" RING IS INSTALLED AT ALL LOCATIONS 

_ _ 586C76 

Fig. 20 2.8L Fuel Pump (VIN X) 

, -rw0 (2) 1/2 inch hex head bolts, turning them 

" alternately and evenly. Tighten to 21 N'-m (15 

ibs. ft.)-

; Fuel outlet pipe. Tighten fitting securely, wh e 

'' holding fuel pump nut with a wrench. 

4. Heat shield 

s Fuel inlet hose and vapor return hose 

[f] Inspect 

(

 Start engine anu check for leaks. 

ELECTRIC FUEL PUMP - REPLACEMENT 

Fig. 21 or 22 

C2 Remove or Disconnect 

1. Relieve fuel pressure, see "Fuel System Pressure 

Relief." 

2. Negative battery cable. 

3. Raise car oh hoist, see Section OA. 

CAUTION: To help avoid personal 

injury when a vehicle is on a hoist, 

provide additional support for the 

vehicle at the opposite end from 

which components are being 

removed. This will reduce the 

possibility of the vehicle falling off of 

the hoist. 

4. Fuel tank (see "Fuel Tank Removal"). 

5. Remove fuel :ank sending unit and pump 

assembly by turning cam lock' ring 

counterclockwise. Lift assembly from fuel tank 

and remove fuel pump from fuel tank sending 

unit. 

0 Pull fuel pump up into attaching hose 'hile 

pulling outward away from bottom support, fake 

care to prevent damage to rubber insulator and 

strainer during removal. After pump assembly is 

clear of bottom support, pull pump assembly out 

of rubber connector for removal. 

Inspect 

• Inspect fuel pump attaching hose for any signs of 

deterioration. Replace as necessary. Also check 

rubber sound insulator at bottom of pump: 

replace if required. 

SPLASH CUP LIQUID 

VAPOR SEPARATOR 

RETURN TUBE 

FUEL TUBE 

RUBBER COUPLER AND

 NN 

SOUND ISOLATOR 

FUEL LEVELSENOER 

ELECTRIC FUEL PUMP 

FUEL FILTER 

Fig. 2 1 In-Tank Fuel Pump - EFI (Typical) 

'JC —^7^ 

- ^7^^ 

"ULSATOR Jjjl 

DAMPER ^ . 

ASSEMBLY \ . y%a 

J y ~ 

i ' 1 fell •! 

I" ft-i, ur^ 

FUEL LEVEL SENOE° \\*J\ 

70-MICRON 

/r^jiE^jH 

FILTER STRAINER 

j CLOSEO CELL FOAM SOUNO 

/ ^ ISOLATOR SLEEVE 

x ^ AC IN-TANK 

^ y ROLLER VANE FUEL MJMR 

*0 RUBBER SOUNO INSULATOR 

J84072849 

B 

Fig. 22 l-V-Tank Fuel Pump - MPFI (Typical) 

Install or Connect 

1. Push fuei pump assembly into attaching hose. 

2. Fuel tank ^ending unit and pump assembly into 

tank assembly. Use new "O" ring during 

reassembly. 

3. Cam lock over assembly and lock by turning 

clockwise. 

4. Reverse fuel tank removal procedure to finish 

installing 

DRAINING FUEL TANK 

NOTICE: If a car is to be stored for anyappreciable length of time, the fuel should be 

drained from the complete system, including 

carburetor or injector nozzles, fuel pump, all fuel 

pipes and the fuel tank in order to prevent gum 

formations and resultant improper engine 

performance. 

1. Remove the negative cable from the battery and 

have a Class B fire extinguisher near the work 

area. 
6C-10 FUEL SYSTEM 

X 

awflr 

r 

"*«! • 

2. Use a hand-operated pump device when possible, 

to drain as much fuel through the filler tube as 

possible. 

3. If a hand-operated pump device cannot be used 

or to complete the draining process, use a siphon 

at the main (not return) fuel pipe at the fuel pump 

or the fuel tank gage unit. 

CAUTION: Never drain or store 

gasoline in an open container due to 

the possibility of fire or explosion. 

4. Reinstall any removed hoses, pipes and cap. 

FUEL GAGE TANK UNIT 

For checking and testing of fuel gages, refer to 

Fuel Gage Diagnosis Chart, in Section 8A. page 80-0 

or 81-0. 

REMOVAL OF TANK AND TANK UNIT 

Tool Required 

J 24187 Fuel Gage (Sending) Unit Remover 

and Installer 

A, J and N Series 

Figs. 23,24 and 25 

0 

1. 

2. 

3. 

4. 

5. 

6. 

7. 

8. 

9. 

10. 

s 

Remove or Disconnect 

Drain tank. 

Hoist car, see Section OA. 

CAUTION: To help avoid personal 

injury when a vehicle is on a hoist, 

provide additional support for the 

vehicle at the opposite er from 

which components are being 

removed. This will reduce the 

oossibility of the vehicle falling off of 

the hoist. 

Tank unit wire from connector. 

Ground wire retaining screw from underbody (if 

used). 

Hoses from tank unit. 

Hoses at tank from filler and vent pipes. 

Support fuel tank and disconnect the two fuel 

tank retaining straps. 

Tank 

Sending unit and gasket using J-24187. 

Sound insulators. 

Install or Connect 

Sending unit and gasket, if removed. 

91 Important 

2. 

3. 

4. 

5. 

6. 

• Use a new gasket. 

Sound insulators. 

Support tank, then tank. 

Straps. Tighten the front fuel tank retaining strap 

bolts to 34 N-m (25 lbs. ft.) and the rear strap nut 

to 12 N*m(106 lbs. in.) 

Hoses to sending unit. 

Hoses to filler and vent pipes. Tighten clamps. 

-131«2B.«p 

Fig. 23 Fuel Tank Mounting - Typical A. J & N Sen^T" 

SL_ 

|71 

y— 

\ 

i ' 

1. SENDER ASM 

2. GASKET 

3. CAM 

W ^ '• 

A$> 

G34G58-4CAN 

Fig. 24 Fuel Gage Tank Unit Installation - Typical 

386C123 

Fig. 25 Fuel Gage Tank Unit Tool 

7. Ground lead to underbody (if used). 

8. Tank sending unit connector. 

9. Lower car. 

10. Refill tank. 

^ 1 Inspect 

• Leaks 
P.50 

FUEL SYSTEM 6C-11 

E3 

H Series 

2l 25 and 26 

Remove or Disconnect 

nrain tank. 

rtois« car, see Section OA. 

JAUTION : TO help avoid personal 

•Irv when a vehicle is on a hoist, 

,n!wide additional support for the 

p

hicle at the opposite end from 

Hirh components are being 

moved. This will reduce the 

ossibilitY of the vehicle falling off of 

the hoist. 

Tank sending unit harness connector. 

Tank filler an d ven t n0ses-

Tank sending unit hoses. 

Lower intermediate exhaust pipe heat shield (4 

screws). 

Support tank, then straps. 

Sending unit and gasket, using J-24187. 

Sound insulators. 

C2 install or Connect 

• Sending unit and gasket, if removed. 

• Gasket must be installed with tangs 

pointing downward. 

|T"[ Important 

• Use new gasket. 

A. • Insert sending unit into tank. 

B. Hold the sending unit so that the plate of the 

sending unit is four inches above the ring on 

the tank. 

C. Rotate the sending unit until the front of the 

fuel sock is pointing forward in the tank. 

D. Lower the sending unit until it contacts the 

ring on the tank. 

E. Position the sending unit in its final place 

and lock with the cam ring. 

2. Sound insulators. 

3. Support tank, then tank. 

4. Straps. Tighten bolts to a torque of 34 N-m (25 

lbs. ft.). 

5. Raise intermediate exhaust pipe heat shield and 

install 4 screws. 

6. Tank sending unit hoses. 

7. Tank filler and vent hoses. Tighten clamps. 

8. Tank sending unit harness connector. 

9. Lower car. 

10. Refill tank. 

L» Inspect 

Leak^ 

VIEW S 

-& 

N 

1. FUEL TANK 

EXHAUST PIPE 

STRAP 

34 N-m (25 LBS. FT.) 

CLAMPS 

SENDER ASSEMBLY 

CAM 

GASKET 

3B3W1739 

>g 26 Fuei Tank Mounting - C & H Series 
P.51 

6C-12 FUEL SYSTEM 

FUEL SYSTEM CLEANING 

CAUTION: This procedure will not 

remove all fuel vapor. Do not attempt 

any repair on tank or filler neck where 

heat or flame is required, as an 

explosion resulting in personal injury 

could occur. 

91 Important 

• Have a Class B fire extinguisher near the work 

area. 

If trouble is due to contaminated fuel or foreign 

material that has been put into the tank, it can usually 

be cleaned. If tank is rusted internally, it should be 

replaced. 

1. Disconnect battery (and engine harness 

connector on HEI distributor 2.8L, VIN X). 

2. Relieve fuel system pressure. See "Fuel System 

Pressure Relief". 

3. Drain fuel tank. (See "DRAINING FUEL 

TANK.") 

4. Remove fuel tank. (See "REMOVAL OF 

TANK.") 

5. Remove the fuel inlet filter and inspect for 

contamination. If filter is plugged, replace. 

(Leave fuel line disconnected.) 

6. Locate tank away from heat, flame or other 

source of ignition. Remove fuel gage tank unit 

and inspect condition of filter. If filter is 

contaminated, a new filter should be installed 

upon reassembly. 

7. Complete draining of tank by rocking it and 

allowing fuel to run out of tank unit hole. 

8. Purge fuel tank, see "Fuel Tank Purging 

Procedure." 

Disconnect fuel feed pipe and use air pressure to 

clean fuel line and fuel return line (if equipped). 

Apply air pressure in the direction fuel normally 

flows through line. 

Use low air pressure to clean pipes on tank unit.. 

Install new filter on fue! tank unit if required. 

Install fuel tank unit, with new gasket, into tank 

and install tank. Connect tank unit wires and all 

fuel pipes except fuel line at the carburetor or 

throttle body. (See "Removal of Tank" for proper 

procedure.) 

12. Disconnect fuel feed hose to chassis pipe at front. 

• On 2.8L (VIN X) disconnect fuel line at 

carburetor. 

13. Connect a hose onto fuel pipe and insert other 

end of hose into an empty one gallon fuel can. 

14. Connect battery cable. 

CAUTION: Make sure engine harness 

connector on HEI distributor is 

disconnected so a spark will not occur 

and cause an explosion while purging 

fuel pump. 

15. Put 23 liters (six gallons) of clean fuel in the tank 

and apply 12 volts to terminal "G" ofthe ALCL 

to pump two liters (two quarts) of fuel into fuel 

can. This will purge fuel pump. 

• 2.8L (VIN X), crank the engine. 

9. 

10. 

11. 

16. Remove hose and connect fuel line. Use new "ry, 

rings as needed (see "Fuel Line "O" Rings"-, 

17. 2.8L (VIN X),-- Connect engine harL 

connector on HEI distributor. ^s 

18. Start engine. 

||y ] Inspect 

• For Leaks 

FUEL TANK PURGING PROCEDURE 

1. Remove fuel gage unit and drain all remain^ 

fuel from tank. 

2. Visually inspect interior cavity of tank. If any fUe) 

is evident, drain again. 

3. Move tank to flushing area (wash rack). 

4. Fill tank completely with tap water, agitate 

vigorously and drain. 

5. Add gasoline emulsifying agent to the tank, refill 

with water, agitate mixture for 10 minutes, drain 

tank completely. 

For correct gasoline emulsifying agent to water 

mixture, refer to the manufacturer's specifications. L'-« 

an available emulsifying agent, such as "Product-Sol 

No. 913" or equivalent. 

6. When empty, refill the tank until it is overflowing 

with water. Completely flush out remaining 

mixture and empty tank. 

7. If available, an explosion meter should be used to 

check for a negative reading. 

8. Perform requi: .d service work. 

FUEL TANK LEAK TEST PROCDURE 

1. Plug all outlet- as follows: 

a. Install filler neck and vent hoses, upper 

neck assembly and install filler cap. 

b. Install fuel tank sending unit with gasket 

and plug fuel line. 

c. Install short piece of fuel line on fuei 

sending unit vent tube. 

2. Apply air pre^ure to tank through vent •.->.-

When air can be heard escaping from filler n«... 

cap (approximately " to 10 kPa or 1 to 1-1/2 ib' 

of pressure) pinch the fuel line hose to retain 

pressure. 

3. Test suspect area for leaks with soap solution or 

by submersion. If leak is noted, replace tank. 

FUEL, FUEL RETURN, AND EMISSION PIPE 

REPAIR OR REPLACEMENT 

If replacement o( a fuel feed, fuel return or 

emission pipe is required, use welded steel tubing 

meeting GM Specification 124M, or its equivalent. The 

replacement pipe must utilize the same type of fitting 

as the original pipe to ensure the integrity ot 

connection. 

NOTICE: Do not use copper or aluminum tubm* 

to replace steel tubing. Those materials do not ha>« 

satisfactory durability to withstand normal vehicle 

vibrations. Only tubing meeting the 124M 

Sepcification is capable of meeting all the pressure 

T 
P.52 

n 

>r 

IT 

ie 

J{ 

>g 

it 

le 

vl 

*e 

FUEL SYSTEM 6C-13 

A vibration characteristics necessary to ensure 

^durability standard required. 

Always check and replace any "O" Rings and/or 

he>s that appear damaged. 

[ t l important 

U-' . minimum of 13.0 mm (1 /2") clearance must be 

tained around sharp edges such as flanges, pinch 

(tiaiMn etc, to prevent contact and chaffing. A minimum 

• o mm'(3/4") clearance must be maintained around 

L moving parts. 

When rubber hose is used to replace pipe, use 

'

 oniy reinforced fuel-resistant hose which is 

identified with the word "Fluroelastomer" on the 

hose. Hose inside diameter must match pipe 

outside diameter. 

Do not use rubber hose within 100mm (4") of any 

' part ofthe exhaust system or within 254mm (10") 

of the catalytic converter. 

In repairable areas, cut a piece of fuel hose 

100mm (4") longer than portion of the line 

removed. 

If more than a 6 inch length of pipe is removed, 

use a combination of steel pipe and hose so that hose 

lenzths will not be more than 254mm (10"). 

Follow the same routing as the original pipe. 

•

 Cut ends of pipe remaining on car square with a 

tube cutter. Using the first step of a double flaring 

tool, form a bead on the end of both pipe sections. 

If pipe is too corroded to withstand the beading 

operation without damage, the pipe should be 

replaced. If a new section of pipe is used, form a 

bead on both ends of it also. 

• Use screw-type hose clamp No. 2494772 or 

equivalent. Slide clamps onto pipe and push hose 

51mm (2") onto each portion of fuel pipe. 

Tighten clamps on each side of repair. 

• Pipes must be properly secured to the frame to 

prevent chafing. 

PORT FUEL INJECTION 

FUEL PIPE REPLACEMENT 

figs. 10,14 through 19, 27, 28, 29 and 30 

Due to the fact that the fuel pipes are under high 

pressure on these systems, they require special 

consideration for service. 

• All fuel feed and return line attachments in the 

system except return lines at the rear of the car. 

are screw fittings type. 

• Always use a back-up wrench when loosening or 

tightening the fittings. 

• Screw fittings used on these two systems utilize 

"O" rings for the fuel feed and return pipes and 

the two sizes of "O" rings are not interchangeable 

(see "Fuel Line "O" Rings'"). 

• Anytime that the fuel or return pipes are 

disconnected, inspect the "O" rings for cut or 

other type of damage and replace as necessarv 

(see "Fuel Line "O" Rings"). 

The flare used on these fuel pipes is not 

compatible with the flare used on normal fuel 

pipes. 

Use correct torque when tightening these fittings. 

If pipes are replaced, always use original 

equipment parts or pans that meet GM 

Specification 124M. 

FUEL FEED PIPE 

FUEL RETURN PIPE 

"0" RINGS(GASKETS) 

27 N«m (20 LBS. FT.) 

8ACK-UP WRENCH HERE 

FUEL FEED HOSE 

FUEL RETURN HOSE 

38*072828 

Fig. 27 J Series Fuel Pipes 4 Hoses - 2.8L 

2 FUEL F5EO HOSE 

~ T FUEL RETURN HOSE 

j T 30 N-m (22 FT. LBS.i 

~B~ MAKE SURE "0 " RING IS 

INSTALLED AT ALL SCREW 

COUPLINGS ALSO USE 

BACK UP WRENCH FOR 

REMOVAL AND INSTALLATION 

588CS4 

Fig. 28 N Series Engine Fuel Pipes & Hoses - 3.0L 

ACCELERATOR CONTROLS 

The accelerator control system is cable type. 

There are no linkage adjustments. 
6C14 FUEL SYSTEM 

h 

mn 

1. FUEL RETURN HOSE 

2. FUEL FEED HOSE 

3. FUEL RETURN PIPE 

4. FUEL FEED PIPE 

5. "O" RING SEALS 

6. 35 Nf " (26 LBS. FT.) 

7. USE BACK-UP WRENCH HERE 

G3A488-6CA 

a. 

b. 

c. 

d. 

Fig. 29 A Series Engine Fuel Pipes & Hoses - 2.8L (VIN 

W) 

Hfl 

* 1 FUEL FEED PIPE 

FUEL RETURN PIPE 

3. CLIP 

4. BOLT - FULLY DRIVEN, SEATED ANO NOT STRIPPED 

5. ACCELERATOR CONTROL CABLE BRACKET 

6. 30 N«m (22 LBS. FT.) 

7. "0 " RING SEALS 

1. 

2. 

8. USE BACK-UP WRENCH HERE 

G34932 6C AE 

Check for correct opening and closing position 

by operating accelerator pedal. Make sure that •>/ 

injection pump or throttle valve reaches wide-orw 

throttle position. If it does not, inspect for damaged 0r 

bent brackets, levers, or other components; or, for p00r 

carpet fit under the accelerator pedal. 

If any binding is present in the linkage, check for. 

1. Proper routing of cable. 

2. Kinked or damaged cable. 

3. Free movement of: 

Throttle lever at carburetor or throttle 

body. 

Cable at throttle body or carbureter stud 

Accelerator lever at bearing support. 

Pedal at lever. 

Whenever disconnecting or replacing parts, lut* 

pivot points with Accelerator Linkage Lubricant 

1052541 or equivalent. 

ACCELERATOR PEDAL AND CABLE 

When performing service on the accelerator 

pedal, observe the following: 

• The mounting surface between support and dash 

panel must be free of insulation. The carpet and 

jute in pedal and tunnel area must be positioned 

to lay flat and be free of wrinkles and bunches. 

• Slip accelerator control cable through slot in rod 

and then install retainer in rod, being sure it !S 

seated. Care must be utilized in pressing the 

retainer into hole in rod to assure the cable is not 

kinked or damaged in any way. 

• After secunr.2. all components ofthe accelerator 

linkage must operate freely without bind between 

full-closed throttle and full wide-open throttle. 

• Wires, hoses, cables or other obstructions must 

not be placed within 13mm (33/64 in.) of cable 

or rod at any point in their travel. 

When performing service on the accelerate: 

control cable, observe the following: 

• Retainer must be installed with tang secur;: 

overhead of >iud. 

• Conduit fitting at both ends ' cable must have 

locking tangs expanded and locked in attachin* 

holes. 

• The braided portion of the accelerator cable 

assembly must not come in contact with the fron! 

of dash sealer during assembly, repair :r 

replacement of the assembly. 

• Flexible components (hoses, wires, conduits, etc 

must not be routed within 50.00mm (2.3 in.) *• 

moving pans of accelerator linkage outboard :: 

support unless routing is positively controlled. 

The accelerator pedal and accelerator contrc. 

cables are shown in Fig. 31 through 44. 

Fig. 3 0 Engine Fuel Pipes & Hoses - 3.0L & 3.8L. A. C & 

H Series 
T FUEL SYSTEM 6C-15 

'(.EVER ASM. 

PLATE 

' g N .m (71 LBS. IN.) 

i" P60AL 

'• RgTAlNER 

*' SPRING'-MUST BE ASSEMBLED WITH 

*•• HOOK RESTING ON PEDAL 

, SUPPORT 

' RETAINER 

J LUBPICANT 

, ' CABLE ASM. 

• .NSULATOR 

1. SUPPORT 

2. RETAINER - ACCEL. CONTROL CA8L': 

3. PLATE 

4. 3N - 25 LBS. IN.) 

5. LEVE- ASM. 

6. PEDA. ASM. 

7. RETA '. = R 

8. SPRIN". 

9. INSOL'TO R 

10. LUBP:AN T 

1 1, CABLE ASM. 

G34970-6CA 

-'•3 31 Accelerator Control, Passenger Compartment - J 

& N Series 

Fig. 32 Accelerator Control, Passenger Compaament 

A Series (C & H Similar) 
P.55 

6C-16 FUEL SYSTEM T 

OAI1Tinw , rAR E MUST BE UTILIZED IN PRESSING CABLE RETAINER INTO HOLE IN DASH PANEi. AND CAUTION CARE MUST 8f eu M L E , s NQ T T 0 B E K1NK ED OR DAMAGED tN -

CARB LEVER 8"A«E T/ T O

 PR * TM TM ° TM HU

AV|N G SECU RED ALL COMPONENTS OF THE 

J^S ^ TM" TM»TM FR"

LY

 ""*«* ^ 

CLOSED THROTTLE AND FULL WIDE OPEN. 

\ 

\ 

*»«*ii 

CABLE ASM. 

[~2~l BRACKET 

[ T l LUBRICANT 

(QUAN.ASREQ'D.) 

\__ RETAINER 

( T l PROTECTOR & 

' ' NUT 

21220) 

Fig. 33 Accelerator Control Cable - 1.8L 

Fig. 34 Accelerator Return Spring 3L 

»'U * l 

CABLE ASM 

RETAINER 

RETAINER MUST BE INSTALLED WITH TANG SECURED 

OVER END OF STUO. CARE MUST BE UTILIZED IN 

PRESSING CABLE RETAINER INTO HOLE IN DASH PAN"'.' 

ANO HOLE IN BRACKET TO PREVENT OAMAGE. CABLE! 

IS NOT TO BE KINKED OR DAMAGED IN ANY AAV j 

DURING ASSEMBLY. HAVING SECURED ALL; 

COMPONENTS OF THE ACCELERATOR LINKAGE AS 

SPECIFIED. LINKAGE MUST OPERATE FREELY BETWEEN! 

FULL CLOSED THROTTLE ANO FULL WIDE OPEN. CA8L*! 

MUST BE ROUTED UNOER SPARK PLUG WIRES TO 

PREVENT GROUNDING OUT AGAINST BRACKET, 

LUBRICANT 

, n-148S76CJ _ 

Fig. 35 Accelerator Control Cable - 2.0L 
P.56 

y 

JREO 

D IN 

ANEL 

ABLE 

WAY 

ALL 

E AS 

WEEN 

ABLE 

S TO 

t CABLE 

2 RETAINER 

3' RETAINER - INSTALL IN OIRECTION SHOWN 

4' MUST BE FULLY SEATED 

5. TRANSAXLE THROTTLE VALVE CABLE 

CA8LE MUST NOT BE KINKED OR DAMAGED 

384072829 

1. PROTECTOR 

2. 12 N-m 1102 LBS. IN.) 

533418-gC 

Fig. 37 N Series Accelerator Control Cable Protector -

2.5L(VIN U) 

Ja 36 Accelerator Control Cable - 2.5L (VIN U), N 

Series 

'• CABLE 

"• P-ETAINER (RETAINER MUST BE INSTALLED 

', WITH TANG SECURED OVER ENO OF STUO) 

3. THROTTLE LEVER 

CARE MUST BE UTILIZED IN PRESSING CA8LE 

RETAINER INTO HOLE IN DASH PANEL AND THROTTLE 

LEVER TO PREVENT OAMAGE. CABLE IS NOT TO 86 

I LINKED OR DAMAGED IN ANY WAY. 

384072832 

hl9 39 Accelerator Control Cable - 2.8L (VIN W), J 

Series 

BOTH LOCKING TANGS MUST BE 

ACC. EXPANOED ANO LOCKED IN BRACKET 

CABLE ATTACHING HOLE-:. 

FASTENER MUST 

BE INSTALLED 

WITH TANG 

• ' RETAINERj^r-V SECURED OVER 

•-*^*,'

r

- " HEAD OF STUD. 

A/C REFRIG. HOSE 

OETENT CABLE 

CONDUCT FITTING AT END OF CABLE 

ASM. MUST HAVE LOCKING TANGS 

EXPANDED AND LOCXED IN EXISTING 

H0LE

- 2B6C211 

Fig. 38 Accelerator Control Cable - 2.5L. A Series 
P.57 

6C18 FUEL SYSTEM 

S 

•JIM WITHOUT A/C 

1. CABLE ASM. 

2. RETAINER 

3. . LUBRICANT 

4. ROUTE CABLE UNDER A/C PIPE AND 

OVER COIL AND SPARK PLUG WIRES 

5. ACCELERATOR CABLE MUST BE ROUTED 

OVER HEATER INLET HOSE 

6. CONDUIT FITTING AT BOTH ENDS MUST 

HAVE LOCKING TANGS EXPANDED 

ANO LOCKED IN ATTACHING HOLES 

G34485-6C A 

s» 

Fig. 4 0 Accelerator Control Cable - 2.8L (VIN Xi A 

Series 

1. CABLE ASM. (CABLE IS NOT TO BE KINKED 

OR DAMAGED >'• ANY WAY DURING 

ASSEMBLY OPE = ATION.) 

2. BRACKET 

3. 25N«m (18 LBS. =T.) 

4. RETAINER 

5. LUBE 

6. BRAKE BOOSTS'- HOSE 

7. ROUTE CABLE 1 UNDER PLENUM ANO 

INSTALL TO BRACKET 

G3449Q6C4 

Fig, 4 1 Accelerator Control Cable - 2.8L (VIN Wi A 

Series 

'«"*! 
P.58 

FUEL SYSTEM 6C-19 

ACCELERATOR CONTROL & CRUISE CONTROL 

' sERVO CABLE 

Q=TAIN6 R - RETAINER MUST BE INSTALLED WITH 

2

 TANG SECURED OVER HEAD OF STUD. 

CONDUIT FITTING AT BOTH ENDS MUST HAVE 

LOCKING TANGS EXPANDED & LOCKED IN ATTACHING 

HOLES. 

4 PROTECTOR 

ACCELERATOR CABLE MUST NOT BE SUBJECTED 

TO SHARP BENOS DURING INSTALLATION. ACCELERATOR 

TABLE MUST BE ROUTED SMOOTHLY & FREELY OF 

yyiRES, HOSES OR OTHER OBSTRUCTIONS BETWEEN 

CONDUIT FITTINGS. 

_____ 384072831 

Fig. 42 Accelerator Control Cable - 3.01. N Series 

CABLE ASM. 

RETAINER 

LUBRICANT 

CONDUIT FITTING AT BOTH ENDS MUST HAVE 

LOCKING TANGS EXPANDED AND LOCKED IN 

ATTACHING HOLES. 

ACCELERATOR CABLE MUST NOT BE SUBJECTED 

TO SHARP BENDS DURING INSTALLATION. 

ACCELERATOR CABLE MUST BE ROUTED SMOOTHLY 

ANO FREELY OF WIRES, HOSES OR OTHER 

OBSTRUCTIONS BETWEEN CONDUIT FITTINGS. 

G34804-8CH 

Fig. 43 Accelerator Control Cable - 3.0L, H Series 

l .^ v. 

SECTION A-A 

A#£Dl •*. 

<&•:• " • 

^y V"^--' • ^ 

VIEW A 

(/••'rCS 

CONOUIT FITTING AT 

30TH ENDS MUST HAVE 

LOCKING TANGS 

EXPANDED AND 

LOCKED IN ATTACHING 

"OLES 

1. RETAINER 

2. THROTTLE LEVER 

3. ACCELERATOR CONTROL 

4. CRUISE CONTROL CABLE 

5. TRANS. T.V, CABLE 

6. COWL 

3B401 1868 

Fig. 44 Accelerator Control Caole 

Series 

3.3L, A, C & H 
P.59 

DRIVEABILITY AND EMISSIONS • CARBURETED 6ESC3-1 

SECTION C3 

EVAPORATIVE EMISSION CONTROL SYSTEM (EECS) 

GENERAL DESCRIPTION 

The 

astern 

:hircoal 

basic Evaporative Emission Control 

EECS) used on all vehicles is the 

canister storage method 'see Fig. C3-U 

method transfers fuel vapor from the fuel 

an activated carbon (charcoal* storage 

icanisten to hold the vapors when the 

le is not operating. When the engine is 

na the fuel vapor is purged from the carbon 

- n fl fl * &' * ' « 

ent bv intake air flow and consumed in the 

' mal combustion process. 

unk to 

.<?<" t L 

11 

fe 

CARBURETOR 

U 1 FUEL TANK 

[___ BLANK 5-1 2-3 5 

' ' S 23;<"-6E 

g-re C3-1 -Vapor Canister • 2.3L A . y.H x' 

EVAPORATIVE EMISSION 

2.8L Engine 

This system (Figure C3-6i has a low volume 

purge that occurs any time the throttle valve is 

opened above idle. Also, a high volume purge 

occurs by the use of an ECM controlled fuel 

vapor purge solenoid. 

• Canister 

A two tube vpaor canister is used to 

absorb and store fuel vapor form the fuel 

tank. The fuel tank is vented through a 

line which leads from the tank to a tank 

pressure control valve which, is connected 

to a tube on the canister marked "Fuel 

Tank". 

VAPOR CANISTER 

Canisters may be classified as * 'pen or Closed 

Bottom types. Replacement of filters is required 

as part of -or ma I servicing of the Open Bottom 

models. 

Gasoli.' vapors from the fuel tank How into 

the tube ! -led "Fuel Tank", and are absorbed 

by the car n. The canister is purged when the 

-ngine is running above idle speed. A timed 

vacuum source is applied to the tube labeled 

"Canister i\,:-.je" to drasv fresh air through the 

bottom of tne canister. The air mixes with the 

vapor and "-.« mixture is drawn into the Intake 

manifold to oe burned. 

FUELTANK PRESSURE CONTROL VALVE 

The Fu^l Tank Pressure Control Valve is a 

spring-biase-; vacuum diaphragm valve, 

normally cl'\»ed. 'Figure C.3-21. When the engine 

is running. . ituum is applied to the valve and the 

valve is opened. Fuel vapors from the fuel tank 

are now free co vent to che canister. When :he 

engine is shut off, no vacuum is appiiea co che 

valve, and ene fuei tank is vented chrou^h che 

restriction in the valve. This restriction tends to 

hold vapor in the tank rather than .ii!n7ni che 

vapor into che canister. 
P.60 

6E1-C3-2 DRIVEABILITY AND EMISSIONS • CARBURETED 

1 MANIFOLD VACUUM TUBE 

~2~ DIAPHRAGM 

T

1

 SPRING 

~ CANISTER TUBE 

T " VENT RESTRICTION 

~T~ TUBE TO FUEL TANK 

-IS 

A second tube is connected 

connection in the vapor vent purge h 

between the vent valve and canister 

Two tubes with a .030" restriction h«u„ 

I J "lWQ n 

them are connected to the fuel ,. 

purge solenoid. 

V" 

n 

r 

Figure C3-2 Fuel Tank Pressure Control Vaive (2.81) 

» Fuel bowl vent solenoid. Figure C3-3. 

The bowl vent valve is a grounded 

solenoid, that is energized by ignition 

voltage. When the solenoid is energized. 

the bowl vent valve is shut off, and is open 

when de-energized. 

Vapors from above the float chambe r in 

the carbureto r are vented to the canister 

when the ignition is shut off. 

1

 Fuel Vapor Connector, Figure C3-4. 

Ported vacuum from the carbureto r is 

supplies to a tube with an .080" restrictor. 

1-^=3^ 

F'jEL VAPOR CONNECTOR 

080 ""ESTRICTION 

030 RESTRICTION 

TO CARB PORT V, ACL'UM 

_"_ TO VAPOP ='. 

SOLENOID 

6 TO "Y " CON.V 

IN CANISTE = 

VENT.PU*"""-" 

Figure C3-4 Fuel Vapor Connector 

Fuel Vapor Purge Solenoid Valve 

Solenoid

 :^ ECM controlled. W^-.-

energized. ••<" vapor purge valve is <nu: 

off. Porte': acuum must pass through :--

.030"' and -•>" restrictors to purge vaoor; 

from the mister. De-energized, crir 

solenoid b;. passes the .030" restrict.:..'-. 

allowing hitjh purge . The foliowi,-; 

conditions rmi-t be met for high pru«"e :• 

occur: 

I75sec(v :» after starting engine. 

Fuel ^.,-".--"i system operating 

"closed '. ---ii". 

Speed a- ".e JO MPH 32 km hi in acco. 

trans, equipped vehicles, or abovr 

1300 RPM in man. trans, equipped 

vehicles. 

Figure C3-3 Fuel Bowi Vent Soierc J 
P.61 

hen 

• hu t 

the 

iors 

the' 

tor. 

ina; 

-' to 

3C*"T "3 ' PORTED v AC_ _'.' 

=0*"T •' = •' 30WL

 v

. E\T 

FUEL 30VVL VENT SOL = \Ci " 

FUE- vAPCR CONNECT; ? 

FuEL VAPOR PURGE SOL. 

TANK PRESSURE CONTROL 

•,-c \- p.jRGi -fOSE 

CANISTER 

TANK V APC-R '. ENT PIPE 

DRIVEABILITY AND EMISSIONS • CARBURETED 6E1-C3-3 

• Evidence of fuel loss or fuel vapor odor can be 

caused by: 

Liquid fuel leaking front fuel lines, fuel 

pump or carburetor 

Cracked or damaged canister 

Inoperative bowl vent valve 

Inoperative purge valve 

Disconnected, misrouted, kinked, 

deteriorated or damaged vapor hoses, or 

control hoses 

Bowl vent hose misrouted 

Air cleaner or air cleaner gasket 

improperly seated 

Leaking or inoperative tank pressure 

control valve 

DIAGNOSIS 

The canister purge solenoid operation is 

covered in CHART C-3 at the end of this section. 

• Visual check of two tube charcoal canister 

Cracked or damaged, replace canister. 

Fuel leaking from bottom of canister. 

Replace canister and check operation of 

total system. 

Check filter at bottom of canister. If dirty, 

pic ;ed. or damaged, replace filter. 

PARTS IN:ORMATION 

PARTNAf.'I GROUP 

Canister, Feel Vapor 3.130 

Solenoid, Fuel Vapor Canister 3.140 

•qurs C3-5 Evaporative Emission System - 2.8L 

i to. 

ove 

ped 

RESULTS OFINCORRECTOPERATION 

• Poor idle, stalling and poor driveability can 

be caused by: 

Inoperative bowl vent valve 

Inoperative purge valv^ 

Damaged canister 

Hoses split, cracked and. or, not 

connected to the proper tubes. 
P.62 

6E1-C3-4 DRIVEABILITY AND EMISSIONS - CARBURETED 

s,. 

1ir,| 

I.M I I I I I I-

.?. CONNECTOR (FRONT VIEW) 

CANISTER 

PURGE 

SOLENOIO 

VALVE 

SOLENOID 

CONNECTOR 

MH 

ECMCONNECTOR 

(BACK VIEW) 

^030 " R6STRICTI' 

'-*•»$<_ . TO CANISTER AN 

N 0 

FUEL VAPOR 

CONNECTOR 

JO BOWL 

VENT "Y" CONNECTION 

080" RESTRICTION 

0 PORTED VACUUM 

AT CARBURETOR 

428 DKGRN/YEL 

439 

PNK.81K 

ECM 1 FUSE 

10 AMP 

•+^^y+- - " • IGNITION 

6-3-85 I.P CONNECTOR 

6-1-85 

'5S1608-6E3 

t 

CHART C-3 

CANISTER PURGE VALVE C^ECK 

2.8L 

CARBURETED 

Caniste r purge is controlled by a solenoid valve that allows 

manifold vacuum to purge the canister when -ie-energized. The 

ECM supplies a ground to energize the solerM i purge off. The 

solenoid is energized no purge , by ground;.-. :he test terminal 

with the ingition "ON" and engine stopped, c CA ith the engine 

runnin g if the following are met: 

• Engine run time iess than specified. 

• Coolant temperatur e below a given value. 

• TPS below a given value. 

If the above are not met, the solenoid valve -s not energized. 

1. Checks to see if solenoid '.> energised and will 

not allow vacuum to pa.->>. 

2. Checks to see if signal to "-.ergi/e solenoid 

(Light "ON"i is present at the solenoid. Light 

"ON" is norma l and would indicate no fault in 

ECM or circuit to solenoid. 

3. Checks co see if solenoid passes vacuum when 

"test" terminal is ungrounde d solenoid deenersrv-d •. It should open and keep the pump 

from V.7.ding up a vacuum. 
P.63 

•in 

.e-

*P 

. DRIVEABILITY AND EMISSIONS • CARBURETED 6E1-C3-5 

CHECK PURGE HOSE CONOITION ANO 

CONNECTIONS. REPAIR AS NECESSARIGNITION ON, ENGINE STOPPED 

GROUND DIAGNOSTIC TERMINAL 

APPLY VACUUM TO CARS. SIDE OF "".=••"*.' 

SOLENOIDIAT SOLENOIO) WITH A -AN D .AC . 

PUMP SHOUL08E A8LE TOGET 3A < = 3 -9 

NOT OK i 

2l| 

| • DISCONNECT SOLENOIO CONNECOR i.ND'NS'AL L 

A TEST LIGHT BETWEEN HARNESS "ERV N i- i 

LIGHT OF* G-* : s 

» CONNECT A TESTUGHT 

PROM EACH HARN 

TERM. TO GROUND 

:CNN ;= ':.fNC D 

LIGHT ON ! 

CHECKFORGROUNDED 

CXT 423 TO ECM TERM 

•*••• FOK.-ICMIS 

"4ULTY SEECH4R--C-: 

OPEN 0<T A39 

:

 = 0 V il'.' : L S ; 

CHART C-3 

CANISTER PURGE VALVE CHECK 

2.8L 

CARBURETED 

; OK 

NO DROP 

• D!$C~NN*CT 

SC. ' D 

DROP3Z 

CHECK"CRGROUNOEO 

CKT 429 * : ECM ":' M 

"" " F " ' : " V " 

- : "-A3* " ' 

- AL L 

j'-pN ! • UNGROUNO DIAGNOSTIC 

•-y\ TERM. ANO NOTE VACUUM. 

SO "PCU8L: 

' 0 ^ N 0 

J . 

NOOROP 

FAULTY 

50LENCO. 
P.64 

DRIVEABILITY AND EMISSIONS - FUEL INJECTION [POR^) 5E3-C3-' 

SECTION C3 

EVAPORATIVE EMISSION CONTROL SYSTEM (EECS) 

GENERAL DESCRIPTION 

j h e basic Evaporative Emission Control 

;Vs*em 

1EECS1 used on all vehicles is the 

rc0 a l canister storage method. 

-This method transfers fuel vapor from the 

i rank to an activated carbon charcoali 

rilge device icanisten to hold the vapor, when 

.ue vehicle is not operating. When the engine is 

-unning. the fuel vapor is purged from the carbon 

J<?ment by intake air flow and consumed in the 

inrtnal combustion process. 

Q>—>o 

J

- M T T I I L l_J_ 

'""Ti 

dr—. 

1 1 1 1 1 1 1 1 1 I 

-rL 

VAPOR PURGE 

SOLENOID 

VAPOR FROM FUEL 

TANK 

. ACLO M 

2.8L, EVAPORATIVE SYSTEM 

"A&J " SERIES (FIGURE C3-1) 

The ECM operates a solenoid valve which 

controls vacuum to the purge valve on the 

charcoal canister. Unde r cold engine or idle 

conditions, the solenoid is turned on r>v the KCM. 

which closes the valve and blocks vacuum to the 

canister purge valve. 

The control valve opens with vacuum applied, 

and closes with no vacuum. This prevents purg e 

to the intake manifold unci conditions of lowported vacuum.suc h as deceleration. 

Ihe ECM turns off the solenoid valve and allows 

purge when: 

• Engine i.> warm 

• After the engine has been running a specified 

time. 

• Above a specified road speed. 

• Above a specified throttle opening. 

3.0L&3.S 

FIGURE C; 

The V. 

controls ' 

charcoal 

condition,, 

which clo<<-

i an i »ter pc 

I he E( M c 

purif ^ h--

• En gin-

• After thtime. 

• A hove .'. 

• Above .'. 

EVAPORATIVE SYSTEM 

operates a solenoid valve which 

aum to the purge pa>>age in the 

•-.ister. L'nder cold engine or idle 

he .-olenoid is turned on h\ the ECM. 

•he valve and blocks vacuum to the 

-olenoid ar.r| allow 

• ngine has been running a -pecir'ed 

,;.-iified road speed. 

•nevitied throttle onening, 

Results of -correct Operation 

2.8L, 3.0L. £ 3.8.L 

It' the • 

power, th-

-noicl i- open, or i-

> c I' . -1 % in g 

am.-ter van purge Co ch- ;:-:.'. k<-

manifold a: ni time,. 1 hi, • an ailou -••vti i ;ii" at 

idle or during warm-up, which van cau- e rough 

or un-itaiii- idle, or too ri. h a in,\'rr :•• 'luring 

u a m LI i). 

"'""ure C3-1 - Vapor Canister • 2 ' . 
P.65 

6 B .C3^0!!!VSAB!UT1AH^ ^ 

) 

If the diaphragm holds vacuum, again tr% 

blow through the hose connected to the C 

tube while vacuum is still being a P p | ieri ^; 

increased flow of air should be observed. | U ; 

the canister must be replaced. 

DIAGNOSIS 

The canister purge solenoid operation' . 

covered in CHART C-3 at the end of this seci,,. 

for the 2.SL.3.0L. and 3.3L engines. 

VISUAL CHECK OF CANISTER 

. Cracked or damaged, replace canister. 

• Fuel leaking from bottom ot canister. repUc . 

canister and check hoses and hose routing 

• Check filter at bottom of canister. If ri;r,, 

plugged, or damaged, replace filter. 

ON-CAR SERVICE 

FUEL VAPOR CANISTER • 2.8L, 3.01, 3.8L 

[77] Remove or Disconnect 

t~Hose s from canister. Mark hoses to in--.,: 

new canister. 

•> Canister. 

0 + «. install or -.nect. 

1. Canister. 

2. Hoses. Ma 

•i-2'--35 

3 I SOLENOID •*-.?-<•*•.« 

i-2 • Vaoc r Caniste r • 3.0L i 3 31 

A,C.Ni. & H Sene s 

FUNCTIONALTEST OF FUEL VAPOR 

CANISTER VALVE 

2.8L 

Apply a short length of hose to che lower tube 

of purge valve, and attempt to blou through it. 

Little or no air should pass into tn." canister. A 

small amount of air u ill pa-« if tn- -. ani-te r has a 

constant purge hoie-. 

With hand vacuum pump, app'r- -...vuum 1-V 

Hg. or -51 kPa> through the cone: . '. ai'-e tube 

i uppe r tube . If the diaphragm ooe - not hold 

vacuum for at least 0 seconds, tht I'.apnragm is 

leaking, and the canister must he : • ;a •.••-<.i. 

,,-e connections are corr-.-.. 

CANISTER PUR^SOLENOID-2.8L,3.0L33 L 

77] Remove or Disconnect B 

;. Negativ e n..-. 

• j . Bolt , cov er. •• '• 

.}. F.lectnvai c- -vcot 

1. Solenoid:;- .mister 

ranle . 

-oienoid . 

ind hoses from 

[771 Install or Connect 

1. Solenoid, co . -r, and bolt. 

2. Hoses and .-•.--••trical connector on soleno.: 

•\. Negative battery cable 
P.66 

' 0 . 

DRIVEA8ILITY AND EMISSIONS • FUEL INJECTION (PORT) 6E3-C3-3 

-. AC-.'. ' 

•iL-. V I'ylSZ 

CC- SOLINC.: . 

C - ^ s C - - •-

 :

 . 

C:\T-CL • -

"•gure C3-3 • Canister Location View • 2.3L A ' Series 

CANISTER HOSES 

Refer . to Vehicle Emis.-ion Control 

information Label for routing of cani-ter hoses. 

When replacing hoses, use 61-tvM or its 

equivalent. 

PARTS INFORMATION 

'ART NAME GROUP 

'anister. Fuel \'apor \. I.'lii 

Solenoid, Fuel Vapor Canister :}. 140 

CANISTER 

SC-ENOiQ C0NN=C*"C*" 

CANiSTER ?L.="GE SCLENCl"? 

^S 06 5 2-5": 

Figure C3-4 Canister Purge Solenoid - 3.01,3.3L 
P.67 

I 

) 

6E3-C3-4 DRIVEABILITY AND EMISSIONS - FUEL INJECTION (PORT) 

EJ E LJ ' MJ (NJ LLJ E 

EEEEHEESlJ 

IP. HARNESS CONNECTOR 

(FRONT VIEW) 

A710J 

24 PIN A-B CONNECTOR 

o lUTo. 

A

y 

-fennnantinaotiti • 

l^npnnnnnnnnr~ 

:D W. n< 

8ACK VIEW OF CONNECTOR 

TO CANISTER PURGE VALVE 

4 — 

ECM 

MANIFOLD 

VACUUM 

CANISTER 

PURGE 

SOLENOIO 

N.O, 

428 0KGRN/YEL — A3 

5-24-85 

G 39 

<C4 PNK.BLK 

I.P. CONNECTOR 

GAGE 

IGN 

1-25-35 

55 '3 0 6*8 

CHART C-3 

CANISTER PURGE VALVE CHECK 

2.8L"A &J " SERIES 

FUEL INJECTION (PORT) 

Canister purge is controlled by a solenoid that allows man,cold vacuum to purge the 

canister when de-energized. The ECM supolies a ground to energize the solenoid i purge off'. 

If the diagnostic test terminal is ungrounded, with the engine stopped or the following is met, 

with the engine running, the purge solenoid is de-energized 'purge on >. 

• Engine run time cfter start more than I min. 

• Coolant tempera.ur e above To C. 

• Vehicle speed above 15 mph. 

• Throttle off idle. 

1. Checks to see if the solenoid is opened or 

closed. The solenoid is normal h energized in 

this step; so it should be closed. 

2. Checks for a complete circuit. Normally there 

is ignition voltage on CKT 59 and the ECM 

provides a ground on CKT 128. A shorted 

solenoid could cause an open circuit in the 

ECM. 

3. Completes functional check b> u ngrnunding 

test terminal. This should rnwrnaiU Heenergize the solenoid and allow the • .im u :-

dro p i purge on i. 

4. Solenoids or r-lays are turned "ON" or "OFF" 

by the ECM internal electronic switches 

called "driver-;". Each drive r is part of a 

group of four called "Quad-Drivers" . Failure 

of one can damage ans other driver within trsr 

set. Solenoid coil resistance must measure 

more than 20 ••nms. Less resistance will cau-'-

early failure ofthe ECM 'DRW EK'. Lsin.'i' 

ohmmeter, check the solenoid coil resistan t 

oi all ECM driver relays and solenoid-. "— 

ECM Wiring Diagrams for coil te:••:•. " 

identification. 
DRIVEABILITY AND EMISSIONS - FUEL INJECTION (PORT) 6E3-C3-5 

THISCHARTONLY COVERS THE SOLENOID 

PORTION OF THE CANISTER CONTROL PURGE 

SYSTEM . TO TEST THE CONTROL VALVE(S) SEE 

DIAGNOSIS UNDER GENERAL DESCRIPTION 

IGNITION "ON". ENGINE STOPPED 

GROUNO DIAGNOSTIC TERMINAL 

AT THE SOLENOIO, APPLY VACUUM! 10" HgOR34kPa 

TO THROTTLE BOOY SIDE OF PURGE SOLENOID. 

UNABLE TO GET 10" Hg OR 34 kPa OF VACUUM 

rx , 

DISCONNECT PURGE SOLENOID. | 

CONNECT TEST LIGHT BETWEEN | 

HARNESS CONNECTOR TERMINALS. 

, LIGHT i 

PROBE EACH HARNESSCONNECTOR 

TERMINAL WITH A 

Ti-. "LIGHT TO 

GROUNO. 

n^ i 

; FAULTY SOLENOID 

| CONNECTOR OR 

| SOLENOID. 

LIGHT ON 

ONE 

"ERMINAL. 

LIGHTBOTH 

TERMINALS. ! 

NO L:GH T 

CHECK FOR 

"PEN CKT' ' 

i'3 ' 

C<T428 OK 

y-'A;n SHORT '"0 

/C'.'AGE NCKT 

Hi AND REPLACE 

jfe, 

C.-"C< -Zn 

C°"S C<"39 

CHECK RESISTANCE ACROSS , 

SOLENOID. SHOULD BE 

20 OHMS OR MORE. 

NCTO K :« 

<__

 : REPLACE BOTH SOLENOIO ANO ECM. 

\ FAULTY 

OR ECM 

" " V 

SE * 

"CNNfC" 

I 

CP 

CHART C-3 

I CANISTER PURGE VALVE 

! 2.8L "A & J" SERIES 

j FUEL INJECTION (PORT) 

1 

ABLE TO GET 10" Hg OR 34 kPa OF VACUUM. 

'!«• JNGROUND DIAGNOSTIC TERMINAL. 

• NOTE VACUUM. 

NO DROP DROPS 

• DISCONNECT 

SOLENOID. 

NO TROUBLE FOUND 

DROPS NO DROP 

-REPAIR SHORTTOGRCUNO 

•NC<"A28 

REPLACE 

SCLENCiC 

I 

•".KT423 CK 

~l 

PAULTY ECM, 

"*- A 

dk BEFORE REPLACNG "CM USE OHMETER ANO CHECK 

RESISTANCE OF EAC- ECM CONTROLLED RELAY ANO 

SOLENOIO COIL 

SEE ECM WIRING Z -CRAM FOR COIL TERMINAL 

IDENTIFICATION * Z " "CLENCiO(S) AND RELAYS) ' C 

3c CHECKED. 

REPLACE ANY RE-.- •' CR SOLENOID IF THE CO'L 

RESISTANCE MEi5uS; 5 LESS THAN 20 OHMS 

'.EAR CODES AN -a CONFIRM "CLOSED LOC ° :"""- " CN AND NO SERVICE ENGINE SC C ..GHT 

3-30-33 

' 5S 'i'jo : 
P.69 

r 

« • * 

6E3-C3-6 DRIVEABILITY AND EMISSIONS - FUEL INJECTION (PORT) 

A 24 PI 

*K.fiyl 

24 PIN A-B CONNECTOR 

ratittDDdtiGadao 

«nnnaDDpDDnzq 

_^_W¥-

TO CANISTER 

i 

CANISTER 

PURGE 

SOLENOIO 

VACUUM FROM 

THROTTLE BOOY 

BACK VIEW OF CONNECTOR 

ECM 

mi 

N.C. 

— 639PNK.BL 

ECM/SOL 

FUSE 

428DK.GRN/YEL - A3 

" / 

" ^ 

10-15-84 

9-20-8S 

1S0U9-6EA 

CHART C-3 

CANISTER PURGE CHECK 

3.0L"H &N " SERIES 

3.8L "A, C,& H SERIES 

FUEL INJECTION (PORT/ 

Canister purge is controlled by a solenoid that allows manifold vacuum to purge the canister 

when energized. The ECM supplies a ground to energize the solenoid 'purge on). 

If the diagnostic test terminal is grounded with the engine stopped or the following is me" 

with the engine running the purge solenoid is energized • purg - on1. 

• Engine run time after start more than 1 minute. 

• Coolant temperatur e above Sii'C • 176T\ 

• Vehicle speed above 5 MPH 18 km Iv. 

• Throttle off idle. TPS signal above .75 volt. 

1. Checks to see if the solenoid is opened or 

closed. The solenoid is normally de-energized 

in this step, sc it should be closed. 

2. Completes functional check by grounding test 

terminal. This should norm.-.liy r-nergi/e the 

• solenoid and allow the vacuum :o drop .purge 

om. 

3. Checks for open or shorted solenoid circuit. 

4. Checks to see if ECM cor. tro-l circuit or 

solenoid is at fault. 

Solenoid coil resistance must measure more 

than 20 ohms. Less resistance will cause early 

failure or' the ECM. Using an ohmmeter. check 

the purge solenoid, coolant fan relay 

resistance before installing a replacement 

ECM. hecaus e they could caus e failure ot '•!•" 

purge circuit. 

5. Checks to see if short to voltage damaged 

original ECM. 
P.70 

DRIVEABILITY AND EMISSIONS - FUEL INJECTION (PORT) 6E3-C3-7 

CHART C-3 

CANISTER PURGE VALVE 

3.0L "N" SERIES, 3.8L "A & C" SERIES 

FUEL INJECTION (PORT) 

© • IGNITION 'ON" . ENGINE STOPPED. 

• AT THE SOLENOID, APPLY 10" VACUUM TO 

| THROTTLE BODY SIOE OF PURGE SOLENOIO . 

_ r 

ABLE TO G£T 10" VACUUM. 

^ 1 

1 

- 7 » GROUND DIAGNOSTIC TERMINAL. 

U\» NOTE VACUUM. 

r-T^ 

UNABLE TO GET 10" VACUUM. 

I 

DISCONNECT PURGE SOLENOIO. 

CONNECT TEST LIGHT BETWEEN 

HARNESS CONNECTOR TERMINAL. 

j NOOROP OROPS 

* DISCONNECT 

SOLENOIO. 

ZLL 

LIGHT J 

NO TROUBLE FOUND. 

'Pll t PROBE EACH HAR-

" 7 NESS CONNECTOR 

j TERMINAL WITH A 

TEST LIGHT TO. 

I GROUND. 

CHECK CKT 428 FOR SHORT TO 

GROUNO IF CKT 428 NOT 

SHORTED TO GROUNO. IT IS 

FAULTY ECM SEE * * 

NO LIGHT 

1 

FAULTY 

SOLENOIO 

1 

LIGHT ON ONE TERMINAL 

I 

NO LIGHT 

i CONNECT A TEST LIGHT BETWEEN 

HARNESS TERMINALS A AND B . 

REPAIR OPEN CKT 639. 

T_ 

NOLIGHT LIGHT 

' LIGHT BOTH TERMINALS 

REPAIR SHORTTO VOLTAGE 

•N CKT428 

I ~ 

"iS'-EAT 'EST USING 

:S:G.NAL:C.M . 

FAULTY SOLENOID 

CHECK FOR OPEN CKT 428 . IF CKT 428 NOT 0 = EN, CHECK RESISTANCE 

ACROSS SOLENOID TERMINALS. SHOULD 3E 20 OHMS OR MORE 

IE 

NOT OK OK 

REPLACE BOTH j J FAULTY ECM CONNECTOR j 

SOLENOID ANO ECM. ! ! TERMINAL A 3 OR ECM i 

* * NOTE. 

BEFORE REPLACNG ECM USE OHMMETER ANO CHEC< 

RESISTANCE OF E*CH ECM CONTROLLED RELAY AND 

SOLENOID COIL 

SEE ECM WIRING jlAGRAM FOR COH TERMINAL 

IDENTIFICATION -'OR SOLENOIOiS) AND RELA <(S) '0 

BE CHECKED. 

REPLACE ANY RELA Y OR SOLENO'D IF THE COH 

RESISTANCE MEASURES LESS THAN 20 OHMS 

CLEAR CODES AND CONFIRM "CLOSED LOOP ' C*:*' " ON ANONO SERVICE ENGINE S : *N ' L.GH T 

9-13-35 

4S090O-JE