Fuel Pump: Description and Operation

Fuel Pump (FP) Module

Typical Electronic Returnless Fuel Pump (FP) Module:

Typical Mechanical Returnless Fuel Pump (FP) Module:

The FP module is a device that contains the fuel pump and sender assembly. The fuel pump is located inside the FP module reservoir and supplies fuel through the FP module manifold to the engine and FP module jet pump. The jet pump continuously refills the reservoir with fuel, and a check valve located in the manifold outlet maintains system pressure when the fuel pump is not energized. A flapper valve located in the bottom of the reservoir allows fuel to enter the reservoir and prime the fuel pump during the initial fill.

Fuel Pump (FP) Module and Reservoir
The FP module is mounted inside the fuel tank in a reservoir. The pump has a discharge check valve that maintains the system pressure after the key has been turned off to minimize starting concerns. The reservoir prevents fuel flow interruptions during extreme vehicle maneuvers with low tank fill levels.