Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
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HOMESERVICE MANUALSBMW1993740IL (E32/2) V8-3982CC 4.0L DOHC (M60)REPAIR AND DIAGNOSISPOWERTRAIN MANAGEMENTIGNITION SYSTEMTESTING AND INSPECTIONSYMPTOM RELATED DIAGNOSTIC PROCEDURES
1993 BMW 740iL (E32/2) V8-3982cc 4.0L DOHC (M60)
Symptom Related Diagnostic Procedures
1993 BMW 740iL (E32/2) V8-3982cc 4.0L DOHC (M60)SECTION 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
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
RENDER: 1.0x
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.