Fuel Pump Module

The fuel pump module is sealed to the fuel tank with a retaining ring and O-ring seal. The module consists of
^ housing and reservoir
^ pump
^ fuel level sender
^ fuel and vapor lines

1. Housing and reservoir - The pump module housing provides the connections for the fuel lines (feed and return) and vapor line, electrical connector, and vent valve. The module housing contains the pump and provides a mount for the fuel level sender. This housing is a reservoir for fuel that prevents fuel starvation during aggressive maneuvers when the fuel level is low. It is constantly filled by the return flow of fuel. A valve just above the inlet filter directs fuel to the pump from either the reservoir or the tank, dependent on which has the higher fuel level.

Fuel is filtered before entering the pump by 1) a 2-stage mesh filter ("sock") attached to the bottom of the housing at the pump inlet and 2) a single-stage mesh filter for the return fuel located within the housing. Neither of these filters is serviced. Problems with these filters (low pressure and/or low fuel flow) indicate a contaminated fuel tank; the tank should be thoroughly cleaned and the pump replaced.

The pump module and housing is spring-loaded to always extend to the bottom of the fuel tank. This insures that all the available fuel in the tank can be consumed.

2. The fuel pump is a single stage, turbine style, 12 volt unit controlled by the PCM. The PCM supplies a 12 volt feed to a relay in the IPJB. This relay controls a 12 volt supply to the fuel pump.

The fuel pump will only operate with the ignition On and the engine running or cranking. With the ignition on, the pump relay is only energized for 2-3 seconds and will be disabled if the PCM does not see reference pulses from the crank position sensor. To re-initialize the pump, the ignition must be turned Off for at least 10 seconds

The pump is capable of delivering over two liters of fuel per minute but is required to supply less than one liter per minute to meet engine demands.

The pump incorporates two check valves to control system pressures. The outlet check valve maintains fuel system pressure after the ignition is turned off to insure quick starts. A pressure relief valve protects the fuel system from damage as a result of excessive pressure.

3. The fuel level sender is a variable resistor that is read by the PCM. The PCM reads the resistance and controls the fuel level gauge in response to the float movements of the sender.

The level sender is mounted on the module housing and is a snap-lock attachment. The sender and the float are serviced as a unit.

4. The fuel and vapor lines from the pump module are multi-layer nylon construction. They are molded to shape to provide the desired routing and are not serviceable or repairable. If they are damaged, kinked, or crimped, the entire pump module must be replaced.