GM Service Manual Online
For 1990-2009 cars only

Always begin diagnosis of the electronic fuel injection system with the Powertrain On-Board Diagnostic (OBD) System Check before proceeding to any other diagnostics. This will reduce diagnosis time and prevent unnecessary replacement of parts. The Powertrain On-Board Diagnostic (OBD) System Check will give direction to further diagnostics, such as Engine Cranks But Will Not Run or a DTC Table. Diagnosis of electronic fuel injection pump, including the fuel injection solenoid, fuel solenoid driver, injection timing stepper motor and engine shutoff solenoid also starts with the Powertrain On-Board Diagnostic (OBD) System Check.

If a driveability symptom exists, refer to the particular symptom in the Driveability Symptoms.

Damage to the injection lines including kinking that causes restrictions or leakage could affect driveability or cause a DTC to set.

Fuel Pipes and Hoses

The diagnosis of fuel odor may be a condition of a leaking fuel feed, or return pipe or hose. Fuel pipes that are pinched, plugged, or miss-routed may cause restricted fuel delivery.