Fuel Pump Relay

PRINCIPLE OF OPERATION, FUEL PUMP RELAY






Fuel Pump Relay--is located on the relay holder on the passenger side. It supplies the fuel pump and oxygen sensor preheater with current

The fuel pump relay is controlled from pin 56 of the control module which is grounded for the relay to operate.

If the engine is started and the ignition then switched off more than 45 seconds, the fuel pump relay will operate for about 2 seconds to allow for pre-injection next time the ignition is switched on. On the other hand, if the ignition is switched on without the engine being started, pre-injection will not take place again unless the ignition has been switched oft for 15 minutes.

The fuel pump relay then operates as soon as the control module receives pulses from the crankshaft position sensor.