Fuel Delivery and Air Induction: Testing and Inspection

NOTE: Refer to TECHNICAL SERVICE BULLETINS for possible modifications and tips concerning fuel systems.

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

ENGINE CRANKS BUT WILL NOT START

^ Large quantity of unmetered air (Vacuum leak)
^ Fuel tank is empty
^ Fuel pump relay defective
^ MAS control unit defective
^ Fuel pump defective
^ Fuel filter plugged
^ Poor fuel quality or contaminated
^ Coolant temperature sensor or circuit defective
^ Fuel pressure regulator defective
^ Fuel distributor defective
^ Fuel injectors defective or clogged
^ Fuel supply lines damaged or misrouted
^ Air flow sensor rest position incorrect
^ CIS-E control unit defective

ENGINE STARTS BUT RUNS ROUGH AND DIES

^ Large quantity of unmetered air (Vacuum leak)
^ Fuel filter restricted
^ Poor fuel quality or contaminated
^ Fuel pump defective (insufficient output)
^ Fuel injectors defective or clogged
^ Fuel pressure regulator defective
^ Fuel supply lines damaged or misrouted
^ Coolant temperature sensor or circuit defective
^ Air flow sensor rest position incorrect
^ Fuel distributor defective
^ Excessive carbon build-up on intake valves
^ CIS-E control unit defective

ENGINE RUNS ROUGH, STUMBLES OR HESITATES ON ACCELERATION

^ Unmetered air leak (Vacuum leak)
^ Fuel filter restricted
^ Poor fuel quality or contaminated
^ Defective fuel injectors (poor spray pattern, clogged or leaking)
^ Fuel pump defective (insufficient output)
^ Fuel supply lines damaged or misrouted
^ Fuel pressure regulator defective
^ Fuel distributor defective
^ Excessive carbon build-up on intake valves
^ CIS-E control unit defective

ENGINE RUNNING ON (IGNITION OFF)

^ Fuel injectors leaking