Fuel Pump

An electric fuel pump is used on fuel injected vehicles. When the ignition switch is turned to the "ON" position, ECM will turn on the electric fuel pump by energizing the fuel pump relay. The ECM will keep the pump on if the engine is running or cranking (ECM is receiving reference pulses from the ignition module). If there are no reference pulses, ECM turns pump off within 2 seconds after key on.

The fuel pump is capable of producing fuel pressure in excess of engine requirements. Excess fuel passes through the pressure regulator and is returned to the tank via the fuel return line. For additional information on fuel pump activation, see appropriate CHART A5, FUEL PUMP RELAY CIRCUIT. For information on fuel system pressure testing, see appropriate CHART A7, FUEL SYSTEM DIAGNOSIS for that system.