Symptom Related Diagnostic Procedures

NOTE: Refer to TECHNICAL SERVICE BULLETINS for possible modifications and tips concerning fuel systems.
Check for fault codes, refer to COMPUTERIZED ENGINE CONTROLS.
Possible causes for symptoms are listed in order of testing priority.

ENGINE CRANKS BUT WILL NOT START

^ Air leaks at the induction system
^ Fuel tank is empty
^ Fuel pump relay defective
^ DME main relay defective
^ Fuel filter plugged
^ Poor fuel quality or contaminated
^ Fuel supply lines damaged or misrouted
^ Fuel pressure regulator defective
^ Fuel pump defective
^ Fuel injectors defective or clogged
^ DME control unit defective

ENGINE STARTS BUT RUNS ROUGH AND DIES

^ Air leaks at the induction system
^ Air leaks at the crankcase
^ Fuel filter restricted
^ Poor fuel quality or contaminated
^ Fuel supply lines damaged or misrouted
^ Fuel pump defective (insufficient output)
^ Fuel pressure regulator defective
^ Carbon on intake valves
^ Fuel injectors defective or clogged
^ DME control unit defective

ENGINE RUNS ROUGH, STUMBLES OR HESITATES ON ACCELERATION

^ Air leaks at the induction system
^ Air leaks at the crankcase
^ Fuel filter restricted
^ Poor fuel quality or contaminated
^ Fuel supply lines damaged or misrouted
^ Carbon on intake valves
^ Defective fuel injectors (poor spray pattern, clogged or leaking)
^ Fuel pump defective (insufficient output)
^ Fuel pressure regulator defective
^ DME control unit defective


ENGINE RUNNING ON (IGNITION OFF)

^ Fuel injectors leaking