From: klee2@uoft02.utoledo.edu
Newsgroups: rec.autos.tech
Subject: Toyota Celica ST Ign'n PICKUP COIL
Date: 23 Aug 92 02:25:56 EST
Organization: University of Toledo, Computer Services

To Whom It May Concerned

I spent around 2 weeks in finding out why my Celica ST stalls, either
at idle or while running. I followed the manufacturer's repair manual
and suspected that the Ignition Module was the source of the problem.
The cost of a new IG module costs US$270.00  8-O, ouch!! I called the
local delar and they told me to check wiring connections. I did, and I
cleaned up all the connectors with FreonTF Solvant and 111-Trichloro-
Ethane. The problem is still there.

Today, my car dead again, could'nt start, and as usual, there is a
Code 6 from the ECU (computer's error code) indicating there is no RPM
(engine revolution) signal sent to the ECU.

So, I went back to my office and broought a digital multi-tester to the
parking lot. I disconnected the joint of the PICKUP COIL, and probed
into it. The Resistance indicated was 1 MEGA Ohms. The specified
resistance of a IIA pick up coil is 140 to 180 ohms. 
I went back to my office and took another digital meter, It showed open
circuit (different types of digital meter).
 
I guess, there I found the problem. 

I removed the pickup coil assembly and brought it
back to my office, and had the resistance checked.

****** This is what happened ******
The resistance was infinity from the second digital meter, after a while
the resistance droped to 165 ohms, which is within the specification.
Then I suspected the effect of temperture on the resistance of this coil,
which is beyond my imagination. Maybe there is some other component in
that little sealed block 1"x3/4"x1/4" whic is temperature sensitive. Anyways,
I put this little block under a hot water pot and had the temperature of
the whole block went up. I took the block out and hooked up a meter. 
There I saw something wierd.
At first, the resistance was high, 500K Ohms, then it dropped.... to
around 176 Okms with a little bit fluctuating, then stable.
I put the block back under the water pot, which is hot but less than boil.
With the Meter connected, I saw the resistance went up (jumped up after
a stable rising) and it was very unstable. Open Loop was indicaated
several times, then after 10 seconds, the restance went back to 180 ohms.
I took the block out and put it in front of the air-conditioner vent.
At certain temperature, the resistance went up pretty high then came down
to normal.
I tried a analog meter. Same phenomena was observed.
 
I am trying to make sure I found the problem.
Your opinion and information would be appreciated.
And hope the abuve discription of the trouble I have would be helpful
to othes.

Model: Celica ST
Year: 1986
Engine Type: 2SE (some CAMRY has the same type of engine)
Ignition Assembly: IIA (integrated Ignition Assembly) which 
means the ignittion coil (the one with high voltage) is in the 
distributor, and the ignition module is on the fire wall above the brake
booster in the ehgine compartment. The pickup coil is in the distributor
as well. There will ba a IIA simble on the original distributor cap.  

K Lee 
Newsgroups: rec.autos.tech