Removal & Installation
See Figure 1
- Disconnect the negative battery cable.
- Remove the fuel tank filler cap.
- Using a siphon hose, drain the fuel tank below 1 / 4 full.
- Block the front wheels and raise and support the rear of the vehicle with jackstands.
- Remove the fuel inlet and outlet hoses from the sending unit Be ready to catch any spilled fuel.
- Remove the sending unit wires.
- Using a brass punch and hammer, remove the sending unit retaining lockring by tapping it counterclockwise.
- Remove the sending unit, which incorporates the electric fuel pump, along with the O-ring seal from the fuel tank. Discard the O-ring.
- Remove and discard the pump inlet filter.
- Disconnect the fuel pump terminal wires.
- Remove the pump outlet hose and clamp.
- Remove the pump top mounting bracket nut and remove the pump.
- Install a new inlet filter on the pump.
- Assemble the pump and bracket. Connect the hose and wiring.
- Install the unit and new O-ring in the tank. The rubber stopper on the end of the fuel return tube must be inserted into the cup in the fuel tank reservoir.
- Install the lockring. Carefully tap it into place until it seats against the stop on the tank.
- Connect the hoses.
- Connect the wiring.
- Lower the truck, fill the tank, run the engine and check for leaks.
- Remove the plug from the test port and engage a test port fitting in its place.
- Connect a fuel pressure gauge to the test port fitting.
- Start the engine and let it idle.
- The pressure gauge should read 14-15 psi (97-103 kPa).
- If the pressure is correct the fuel pump is operating normally.
- If the pressure is not correct, adjust the fuel pressure regulator to obtain the correct pressure by turning the screw at the bottom of the regulator inward to increase pressure or outward to decrease pressure.
- If the fuel pressure is considerably above specification and adjusting fails to lower it within specification, inspect the return line for an obstruction.
- If the fuel pressure is considerably below specification and adjusting fails to raise it within specification, momentarily pinch off the return line and recheck the pressure. If pressure has risen, replace the regulator. If it has not, check the filter and supply line for an obstruction.
Fuel pressure will rise to as much as 95 psi (655 kPa) when the return line is pinched shut. Shut the engine down immediately after pinching off the return line.