OPERATION
Fuel is returned through the fuel pump module and back into the fuel tank through the fuel filter/fuel pressure reg-
ulator. A separate fuel return line from the engine to the tank is not used.
The fuel tank assembly consists of: the fuel tank, fuel pump module assembly, fuel pump module locknut/gasket,
and fuel tank check valve (refer to Fuel Tank Check Valve for information).
A fuel filler/vent tube assembly using apressure/vacuum,1/4 turn fuel filler cap is used. The fuel filler tube contains
a flap door located below the fuel fill cap.
Also to be considered part of the fuelsystem is the evaporation control system. This is designed to reduce the
emission of fuel vapors into the atmosphere. The description and functionof the Evaporative Control System is
found in Emission Control Systems.
Both fuel filters (at bottom of fuel pump module and within fuel pressure regulator) are designed for extended ser-
vice. They do not require normal scheduled maintenance. Filters should only be replaced if a diagnostic procedure
indicates to do so.
STANDARD PROCEDURE
STANDARD PROCEDURE - FUEL SYSTEM PRESSURE RELEASE
Use following procedure if the fuel injector rail is, or is not equipped with a fuel pressure test port.
1. Remove fuel fill cap.
2. Remove fuel pump relay from Power Distribution Center (PDC). For location of relay, refer to label on underside
of PDC cover.
3. Start and run engine until it stalls.
4. Attempt restarting engine until it will no longer run.
5. Turn ignition key to OFF position.
CAUTION: Steps 1, 2, 3 and 4 must be performed to relieve high pressure fuel from within fuel rail. Do not
attempt to use following steps to relieve this pressure as excessive fuel will be forced into a cylinder cham-
ber.
6. Unplug connector from any fuel injector.
7. Attach one end of a jumper wire with alligator clips (18 gauge or smaller)to either injector terminal.
8. Connect other end of jumper wire to positive side of battery.
9. Connect one end of a second jumper wire to remaining injector terminal.
CAUTION: Powering an injector for more than a few seconds will permanentlydamage the injector.
10. Momentarily touch other end of jumper wire to negative terminal of battery for no more than a few seconds.
11. Place a rag or towel below fuel line quick-connect fitting at fuel rail.
12. Disconnect quick-connect fitting at fuel rail. Refer to Quick-Connect Fittings.
13. Return fuel pump relay to PDC.
14. One or more Diagnostic Trouble Codes (DTC’s) may have been stored in PCMmemory due to fuel pump relay
removal. The DRB
scantoolmustbeusedtoeraseaDTC.
STANDARD PROCEDURE - DRAINING FUEL TANK - EXCEPT DIESEL
WARNING: The fuel system may be under constant fuel pressure even with the engine off. This pressure
must be released before servicing fuel tank.
Two different procedures may be used to drain fuel tank: through the fuel fill fitting on tank, or using a diagnostic
scan tool to activate the fuel pump relay. Due to a one-way check valve installed into the fuel fill opening fitting at
the tank, the tank cannot be drained conventionally at the fill cap.
The quickest draining procedure involves removing the rubber fuel fill hose at the fuel tank.
As an alternative procedure, the electric fuel pump may be activated allowingtanktobedrainedatfuelrailcon-
nection. Refer to diagnostic scan tool for fuel pump activation procedures. Before disconnecting fuel line at fuel rail,
release fuel pressure. Refer to the Fuel System Pressure Release Procedure for procedures. Attach end of special
test hose tool number 6631 or 6539 at fuel rail disconnection (tool number 6631isusedon5/16”fuellineswhile
tool number 6539 is used on 3/8” fuel lines). Position opposite end of this hose tool to an approved gasoline drain-
ing station. Activate fuel pump and drain tank until empty.
If electric fuel pump is not operating, fuel must be drained through fuel fill fitting at tank. Refer to following proce-
dures.
1. Release fuel system pressure.
2. Raise vehicle.
3. Thoroughly clean area around fuel fill fitting and rubber fuel fill hoseat tank.
4. If vehicle is equipped with 4 doors and a 6 foot (short) box, remove left-rear tire/wheel.
5. Loosen clamp and disconnect rubber fuel fill hose at tank fitting. Usingan approved gas holding tank, drain fuel
tank through this fitting.
SPECIFICATIONS
FUEL SYSTEM PRESSURE
58 psi +/- 2 psi
TORQUE - EXCEPT DIESEL
DESCRIPTION N-m Ft. Lbs. In. Lbs.
Accelerator Pedal Bracket
Mounting12 - 105
Accelerator Pedal Position
Sensor Bracket-to-Battery
Tray Bolts3-30
Crankshaft Position
Sensor - 3.7L28 21 -
Crankshaft Position
Sensor - 4.7L28 21 -
