Fuel Pump: Description and Operation

Fig. 1 Fuel Pump Module:

OPERATION
The electric fuel pump is located in and is part of the fuel pump module. It is a positive displacement, roller vane, immersible pump with a permanent magnet electric motor.

The fuel pump module is suspended in fuel in the fuel tank. The pump draws fuel through a strainer and pushes it through the motor to the outlet. The pump contains a check valves. The valve, in the pump outlet, maintains pump pressure during engine off conditions.

The fuel pump relay provides voltage to the fuel pump.

The fuel pump has a maximum deadheaded pressure output of approximately 880 kPa (130 psi). The regulator adjusts fuel system pressure to approximately 338 kPa (49 psi).

CIRCUIT OPERATION
Circuit A14 is a bus bar in the Power Distribution Center (PDC) and connects to battery voltage. The contact side of the fuel pump relay connects circuit A14 and circuit A141. A 20 Amp fuse in the PDC protects circuits A14 and A142.

Circuit A141 supplies voltage for the fuel pump motor. Circuit Z1 provides ground for the fuel pump motor. The grounding point for circuit Z1 is the right rear wheel house.

Circuit F12 supplies voltage to the coil side of the fuel pump relay The Powertrain Control Module (PCM) controls the ground path circuit for the coil side of the fuel pump relay on circuit K31. Circuit K31 connects to cavity 74 of the PCM.