Fuel Pump

An electric fuel pump (located inside fuel tank as integral part of fuel gauge sending unit) delivers fuel under pressure to throttle body assembly. Fuel pump relay controls fuel pump operation. When ignition switch is turned to "ON" position, fuel pump relay activates fuel pump for 2 seconds to prime injector. If ECM does not receive reference pulses from distributor (engine cranking) after this period, ECM deactivates fuel pump relay. Fuel pump relay will be activated again when ECM receives distributor reference pulses.

As back-up system to fuel pump relay, fuel pump can also be turned on by oil pressure sender. Oil pressure sender has 2 internal circuits. One circuit operates oil pressure indicator in instrument panel. Second circuit is a normally open switch which closes when oil pressure reaches about 4 psi (.3 kg/cm² ). If fuel pump relay fails, oil pressure sender will close and run fuel pump.