Fuel Pump: Description and Operation

PURPOSE
Provides pressurized fuel to the fuel injectors.

CONSTRUCTION
Is a combined assembly with a fuel level sensor, a nylon pickup screen, an internal relief valve and a discharge check valve.

OPERATION
The fuel pump is a high pressure "pumping" unit capable of supplying 150.0 L. (39.7 gal) of fuel per hour at a working pressure of 269.0 kPa (39.0 psi) at 13.2 volts.

Is mounted with its inlet at the bottom of the fuel tank reservoir. This design permits fuel pump operation during extreme vehicle maneuvers and driving on steep hills with low levels of fuel.

Pump Pressure and Contamination Protection
The nylon "pick-up screen" at the pump inlet, filters out dirt and contaminants that could plug or damage fuel pump components.

The internal "relief valve" is designed to protect the fuel pump module from overpressurizing if the fuel flow becomes restricted (for example a clogged fuel filter). Overpressure is limited to 850 kPa (123 psi) of fuel pump (not fuel system) pressure and reduced fuel flow will result.

The pump discharge "check valve" maintains fuel system pressure after the key has been turned off, to minimize starting problems.