Fuel Pump: Description and Operation

Roller Vane Fuel Pump - Exploded View:

Fuel Pump And Sender (Typical):

PURPOSE:
To supply fuel to the fuel injectors.

OPERATION:
Fuel is supplied to the system from an in-tank positive displacement roller vane pump. Fuel pressure is achieved by the rotation of the armature driving roller vane components. The impeller at the inlet end serves as a vapor separator and precharger for the roller vane assembly. The unit operates at approximately 3500 rpm.

The pressure relief valve in the pump will control maximum fuel pump pressure to 41-47 psi. The fuel pump delivers more fuel than the engine can consume even at wide open throttle/full load. Excess fuel flows through the pressure regulator and back to the tank via the return line. The constant flow of fuel means that the fuel system is always supplied with cool fuel, thereby preventing the formation of fuel vapor bubbles.