Driver Complaint Sheet
Engine performance problem (odor, surge, fuel economy...)
Emission Problem
If the test bulb is not on, normal checks that would be performed on cars without C-4 should be done first. If generator or coolant light is on with test bulb, diagnose those first.
Inspect for poor connections at coolant sensor, M/C solenoid, etc., and poor or loose vacuum hoses and connections. Repair as necessary.
- Intermittent test bulb light but no trouble code stored:
- Check for poor connection in circuit from:
- Distributor tach terminal to ECM terminal A.
- Ignition terminal 1 to ECM terminal U.
- ECM terminal T to ground.
- Tach filter resistance should be 14, 000-18, 000 ohms between distributor and ECM terminals (with 1 end disconnected) and open circuit to ground.
- Battery voltage below 9 volts.
- Loss of long term memory. Momentarily grounding M/C solenoid dwell wire connector with engine idling should cause trouble code "23", which should be retained after engine is stopped and restarted. If voltage is present at long term memory terminal (S) but code was not flashed. ECM is defective.
- Check for poor connection in circuit from:
- Acceleration Stumble.
See Chart No. 5 (Adaptive Vacuum Switch Circuit Test).
- All Other Complaints.
Perform System Performance Check on warm engine (upper radiator hose HOT).
NOTE: Any time engine is first started, even if warm, it must be operated at partial throttle for 3 minutes or until dwell starts to vary before proceeding with any test. Also, install test bulb before performing tests.