Fuel Pump: Description and Operation

FUEL PUMP CONTROL
When the key is first turned "ON" (key in "RUN" position with engine "OFF"), the Engine Control Module (ECM) will turn the fuel pump relay "ON" for two seconds. This allows the fuel pump to build up the fuel pressure for cranking. If the engine is not started within two seconds, the ECM will shut the fuel pump "OFF" and wait until distributor reference pulses are present. As soon as the engine is cranked, the ECM will turn the relay "ON" and "RUN" the fuel pump. The Oil pressure switch is provided as a backup to the fuel pump relay.

The ECM will monitor the fuel pump circuit for proper operation and set the appropriate ECM code if necessary.

The ECM monitors voltage on the fuel pump power CKT 120 to detect fuel pump voltage supply faults.