Fuel Pump: Description and Operation

Modular Sender - Fuel Flow:

Fuel Pump

Purpose
An electric fuel pump located in the modular sender assembly is used to provide fuel pressure. To control fuel pump operation, a fuel pump relay and fuel pump switch (oil pressure switch) are used.

Operation
When the ignition lock cylinder is turned to "RUN" position, the fuel pump relay activates the electric fuel pump for approximately two seconds to prime the injectors. If the ECM does not receive reference pulses from the distributor/crankshaft sensor after this time, the ECM opens the fuel pump relay ground circuit. The relay will reactivate the fuel pump when the ECM receives crankshaft sensor reference pulses or when oil pressure raises.

Fuel Pump Strainer

Purpose
A woven plastic strainer is located on the lower end of the fuel sender. This filter prevents dirt from entering the fuel line and also stops water unless the filter becomes completely submerged in water, This filter is self cleaning and normally requires no maintenance. Fuel stoppage at this point indicates that the fuel tank contains an abnormal amount of sediment or water. Therefore, should this occur, the fuel tank should be removed and thoroughly cleaned and the tank filter replaced.