Date: 201707
Local time of day: 0601-1200
Location: ZZZ.Airport, US
Flight conditions: VMC
Light: Daylight
Aircraft: Decathlon 8KCAB
Operator: Personal
Operating under: Part 91
Flight plan: VFR
Mission: Personal
Flight phase: Descent
Airspace: Class D ZZZ
ATC / advisory: Tower ZZZ
Aircraft component: Monitoring System
Component problem: Malfunctioning
Reporter organization: Personal
Reporter function: Pilot Flying; Single Pilot
Reporter qualification: Flight Crew Private
Human factors: Human-Machine Interface; Situational Awareness
Anomaly: Aircraft Equipment Problem Less Severe; Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Maintenance; Inflight Event / Encounter Fuel Issue
Detector: Person Flight Crew
When detected: In-flight
Result: Flight Crew Diverted; Flight Crew Landed As Precaution; General Maintenance Action
Contributing factors: Human Factors
Primary problem: Human Factors

Narrative: I recognized that fuel calculations/usage was incorrect and elected to make a precautionary landing on a clear straight road with control rather than proceeding the 6 miles over housing to airport. While this situation is 100% my responsibility there are a few factors that worked against me in the lead up to this situation.1. Aircraft was 'rushed' out the door by [maintenance facility] due to pressure from aircraft owner. This was due to the [maintenance facility] taking a far longer time to repair than originally quoted. The aircraft underwent an annual inspection however I was never informed that they had changed the EDM930 engine monitoring system. Fuel tanks filled at [maintenance facility].2. Departed VFR with the possibility of weather closing in. After 30 minutes flight time aircraft started a pronounced right roll that had to be held off. Elected to land at [at a nearby airport] due weather and to inspect aileron roll problem.3. [The maintenance facility] found the right aileron linkage jamb nuts loose and vibration was pulling out of adjustment. Adjusted 3 full turns and tightened these nuts and flight the next day was improved with only slight correction required. **Should have filled tanks [there] as I had no weight and balance restrictions**4. Submitted my flight plan trusting the EDM930 fuel flow results of 6.5 GPH. Not sure why I believed this figure however the EDM930 has always been VERY accurate. I did not know at the time that the [maintenance facility] had messed up this unit. Departed with sight gauges reading 3/4 on the ground and full in flight.5. Inflight I noticed the EDM930 reading 35% power and started to mistrust this unit. After referring back to the wing tank sight gauge I noticed it quickly moved from 1/4 tanks to Empty. Diverted my plan towards [a nearby alternate] and notified ATC that I had a fuel problem.I continued flight towards [the alternate] and had landing clearance. Engine started to run lean and rough. Notified ATC of location and landed with power and control. [ATC assisted with services required]. I refueled [and continued uneventfully].




Synopsis: American Champion 8KCAB pilot reported executing a precautionary landing on a road after realizing the engine monitoring system fuel indications were incorrect and fuel was inadequate to make airport.