Symptom Related Diagnostic Procedures

NOTE: Possible causes for the symptoms below are listed in order of testing priority.

ENGINE CRANKS BUT WILL NOT START
1. Faulty spark plugs or ignition wires
2. Faulty high voltage distributor cap or ignition rotor
3. Defective ignition coil(s)
Oscilloscope Patterns and Waveforms

4. Defective crankshaft position sensor
5. Defective cylinder identification sensor
Computers and Control Systems

6. Defective ignition switch
7. Defective Primary ignition wiring
8. Defective Digital Motor Electronic (DME) control unit, Computers and Control Systems


IMPROPER ENGINE IDLING OR STALLING
1. Faulty spark plugs or ignition wires
2. Faulty high voltage distributor cap or ignition rotor
3. Defective ignition coil(s)
Oscilloscope Patterns and Waveforms

4. Defective crankshaft position sensor, Computers and Control Systems

5. Defective primary ignition wiring

POOR ACCELERATION
1. Defective secondary ignition wires
2. Faulty high voltage distributor cap or ignition rotor
3. Defective ignition coil(s)
Oscilloscope Patterns and Waveforms

4. Defective crankshaft position sensor
5. Defective DME control unit
Computers and Control Systems

SPARK KNOCK (PINGING)
1. Defective knock sensor
2. Defective crankshaft position sensor
3. Defective DME control unit
Computers and Control Systems

4. Engine overheating