Fuel Pump: Service and Repair

Fig. 1 High pressure inline electric fuel pump. Typical:

HIGH PRESSURE INLINE PUMP

1. Remove high pressure inline pump assembly as follows:
a. Place vehicle on to a suitable hoist. Do not raise vehicle at this time.
b. Depressurize fuel system as described previously.
c. Raise and support vehicle.
d. Disconnect electrical connector from body wiring harness, then remove inlet and outlet lines from fuel pump.
e. Bend retaining tab outward, then slide fuel pump from assembly.
f. The electrical wiring harness may be removed from assembly by inserting a suitable screwdriver or knife between connector and retaining clip, then sliding connector toward the pump inlet, Fig. 1.
2. To install proceed as follows:
a. Ensure fittings on fuel pump have gaskets properly positioned and that fittings have been properly torqued. Torque inlet fitting to 19---22 ft. lbs. and outlet fitting to 8 - 12 ft. lbs.
b. Ensure wiring harness boots are completely pushed into the fuel pump terminals far enough to seal wire hole and wire terminals are properly pushed onto the fuel pump terminals.
c. Wrap the isolator around the fuel pump, then locate slot in isolator so it faces the bracket base. Push the fuel pump and isolator assembly into the bracket.
d. Ensure tab on isolator contacts bracket tab and bracket tabs do not contact fuel pump base assembly.
e. With the fuel pump completely inserted into the bracket assembly and the wiring harness protrudes out from the bottom ring, bend rear support tab to prevent fuel pump from sliding out.
3. Connect inlet and outlet fuel lines to pump assembly.
4. Connect fuel pump electrical harness connector to body connector, then connect assembly onto fuel pump ring.
5. Start engine and check for pump operation and for fuel leaks.




LOW PRESSURE IN-TANK PUMP

The low pressure fuel pump is located in the top of the fuel tank and requires removal of the fuel tank for proper servicing.
1. Remove fuel tank as follows:
a. Drain fuel from fuel tank.
b. Disconnect and cap fuel lines and hoses.
c. Remove retainer attaching screw from fuel tank flange, if equipped.
d. Disconnect all electrical connectors from fuel tank.
e. Place suitable supports under fuel tank, then remove tank straps and fuel tank.
2. Clean fuel pump mounting flange and fuel tank mounting surface.
3. Disconnect electrical connectors and fuel lines from fuel pump.
4. Remove locking ring and pump assembly from fuel tank.
5. To install pump proceed as follows:
a. Apply a light coat of heavy duty grease on seal ring and install into fuel ring groove.
b. Carefully install fuel pump and bracket assembly. Ensure locating keys are in keyways and seal ring remains in ring groove.
c. Secure pump assembly in place and install locking ring hand tight. Ensure locking tabs are under tank lock rings tabs.
d. Secure fuel pump with locking ring by rotating clockwise until rings contacts ring stop.
e. Connect electrical connectors and fuel lines.
f. Install fuel tank into vehicle and tighten fuel tank support straps.
g. Add fuel to fuel tank and check for leaks.
h. Install pressure gauge tool T80L-9974-A or equivalent on to fuel charging assembly fuel diagnostic valve and turn ignition switch to ON position for 3 seconds.
i. Turn ignition switch OFF and ON for 3 seconds repeatedly 5 to 10 times until pressure gauge indicates at least 35 psi.
j. Check all lines and fittings from fuel leakage.
k. Remove pressure gauge, start engine and check for fuel leakage.