The fuel pump is electric and is fitted to the top of the fuel tank. The pump module may also incorporate the filter/pressure regulator and rollover valve. The fuel gauge sending unit and float are also a part of this module.
The pump has a permanent magnet electric motor. Fuel is pulled through a filter at the bottom of the module and pushed through the electric motor gear set to the pump outlet.
The pump outlet contains a one-way check valve to prevent fuel flow back into the tank and to maintain fuel supply line pressure when the pump is not running. It is also used to keep the fuel supply line full of gasoline.
When the engine has been idle for some time, fuel pressure may drop to zero as the liquid contracts. This is normal.
REMOVAL & INSTALLATION
- Depressurize the fuel system.
- Drain the fuel tank.
- Remove the fuel tank from the vehicle.
- Disconnect any lines that may remain attached to the pump.
- Thoroughly clean the area around the pump so that foreign matter won't fall into the tank when the unit is removed.
- Check the top of the pump for arrows or alignment marks. Check for corresponding marks on the tank itself. Alignment of the pump is important for routing of wiring and lines. Matchmark the pump and tank as reference for assembly.
- If the pump is equipped with "fingers" and "finger locks", apply some lubricant to the assembly.
- Remove the pump locknut. Some units are fitted with a lock tab. Pry it back while removing the locknut.
- Clean the filter at the bottom of the module.
- Reverse the removal procedure.
- Use a new gasket.
- Align pump and tank marks to ensure correct routing of wires and lines.
- If the locknut is the type without fingers and finger locks, tighten the nut to 40 ft. lbs. (54 Nm).
This test requires the use of special factory fuel pressure gauge tool set No. 5069, or equivalent (0-60 psi/0-414 kPa).
- Remove the cap from the fuel rail test port. Connect the gauge.
- Start and run the engine.
- Fuel pressure at idle should be 44.2-54.2 psi (305-373 kPa).
- If pressure is too low, check for kinked hoses. If none are found, suspect the pump.
- If pressure is too high, suspect the regulator.
- Be sure to replace the test port cap after completing the test.