Fuel Pump: Description and Operation

PURPOSE
The fuel pump supplies fuel under pressure to the injection manifold assembly.

LOCATION
The fuel pump is located in the fuel tank.

High Pressure Elecric Fuel Pump:

CONSTRUCTION
The fuel pump is a submersed circumference flow pump comprised of a DC motor, impeller, pump casing, and pump cover. The assembly utilizes an inlet filter, a pressure relief valve, and a check valve.

Control Relay Location:

OPERATION
The fuel pump is controlled by the ECU through the control relay. Fuel enters the inlet port through the tank filter and flows inside the motor to the discharge port. The discharge port contains a check valve to maintain residual fuel pressure when the pump is shut off. If fuel flow to the injection manifold is obstructed, fuel pressure is bypassed to the inlet port by the pressure relief valve.

For a more detailed description of the control relay, refer to COMPUTERIZED ENGINE CONTROLS.
NOTE: Failure of the control relay may interrupt power supply to the fuel pump, injectors and/or the ECU, resulting in start failure.