Fuel Delivery and Air Induction: Testing and Inspection

NOTE: Refer to TECHNICAL SERVICE BULLETINS for possible modifications and tips concerning fuel systems. Check for fault codes, refer to COMPUTERS AND CONTROL SYSTEMS.


ENGINE CRANKS BUT WILL NOT START

^ Air leaks at the induction system
^ Fuel tank is empty
^ Fuel pump relay defective
^ ECM 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
^ ECM defective

ENGINE STARTS BUT RUNS ROUGH AND DIES

^ Idle air control valve defective
^ 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
^ Throttle valve shutting off incomplete
^ Throttle position sensor circuit open or shorted
^ Injector circuits open or shorted
^ Injectors damaged
^ Fuel pump relay defective
^ ECM 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
^ ECM defective

ENGINE RUNNING ON (IGNITION OFF)

^ Fuel injectors leaking