Fuel Pump Module
The fuel pump module assembly is located in the top of the fuel tank. See Fig 1 . The complete assembly contains the following components:
- A combination fuel filter/fuel pressure regulator.
- A separate fuel pick-up filter (strainer).
- An electric fuel pump.
- A threaded lock nut to retain module to fuel tank.
- A gasket between the fuel tank flange and fuel pump module.
- A fuel gauge sending unit (fuel level sensor).
- Fuel supply tube (line) connection.
A 12-volt permanent magnet, electric motor powers the fuel pump. The electric fuel pump is not a separate, serviceable component. Voltage to operate the electric fuel pump is supplied through the fuel pump relay. Fuel is drawn in through a filter (strainer) at the bottom of the module and pushed through the electric motor gearset to the pump outlet. See Figure and Fig 1 .
The fuel pump outlet contains a one-way check valve to prevent fuel flow back into the fuel tank and to maintain fuel supply line pressure (engine warm) when pump is not operational. After the vehicle has cooled down, fuel pressure may drop to 0 psi (cold fluid contracts), but liquid gasoline will remain in fuel supply line between the check valve and fuel injectors. Fuel pressure that has dropped to 0 psi on a cooled down vehicle (engine off) is a normal condition.
The fuel gauge sending unit, pick-up filter, and fuel filter/fuel pressure regulator may be serviced separately. If the electrical fuel pump requires service, the entire fuel pump module must be replaced.