Fuel Pump: Description and Operation

DESCRIPTION AND OPERATION
When the key is first turned "ON" without the Engine running, Engine Control Module (ECM) will turn the Fuel Pump Relay "ON" for two seconds. This builds up the Fuel pressure quickly. If the Engine is not started within two seconds, the ECM will shut the Fuel Pump "OFF" and wait until the Engine starts. As soon as the Engine is cranked, the ECM will turn the Relay "ON" and run the Fuel Pump. An inoperative Fuel Pump would cause a no start condition. A Fuel Pump which does not provide enough pressure can result in poor performance, (refer to Diagnosis by Symptom / Charts A-5 and A-7). Testing and Inspection