hydrocarbons. Vapors from the fuel tank are collected
in a charcoal filled canister. The vapors are held in
the canister until the engine is operating. When the
engine is running, the vapors are drawn through the
intake manifold into the combustion chambers.
PRESSURE-VACUUM FILLER CAP
The loss of any fuel or vapor out of the filler neck
is prevented by the use of a safety filler cap. The cap
will release pressure only under significant pressure
of 10.9 to 13.45 kPa (1.58 to 1.95 psi). The vacuum
release for all gas caps is between 0.97 and 2.0 kPa
(0.14 and 0.29 psi). The cap must be replaced by a
similar unit if replacement is necessary.
WARNING: REMOVE FILLER CAP TO RELIEVE
TANK PRESSURE BEFORE REMOVING OR REPAIR-
ING FUEL SYSTEM COMPONENTS.
QUICK-CONNECT FITTINGS
Different types of quick-connect fittings are used to
attach various fuel system components. These are: a
single-tab type, a two-tab type or a plastic retainer
ring type. Some are equipped with safety latch clips.
Refer to the Removal/Installation section for more
information.
CAUTION: The interior components (o-rings, spac-
ers) of quick-connect fitting are not serviced sepa-
rately. Do not attempt to repair damaged fittings or
fuel lines/tubes. If repair is necessary, replace the
complete fuel tube assembly.
Fuel tubes connect fuel system components with
plastic quick-connect fuel fittings. The fitting con-
tains non-serviceable O-ring seals (Fig. 4).
CAUTION: Quick-connect fittings are not serviced
separately. Do not attempt to repair damaged quick-
connect fittings or fuel tubes. Replace the complete
fuel tube/quick-connect fitting assembly.
The quick-connect fitting consists of the O-rings,
retainer and casing (Fig. 4). When the fuel tube
enters the fitting, the retainer locks the shoulder of
the nipple in place and the O-rings seal the tube.
DIAGNOSIS AND TESTING
FUEL PUMP PRESSURE TEST 2.4/3.3/3.8L
WARNING: FUEL SYSTEM PRESSURE MUST BE
RELEASED BEFORE A FUEL SYSTEM HOSE OR
COMPONENT IS DISCONNECTED.The fuel system operates at approximately 338 kPa
(49 psi), 3.3L uses approximately 379 kPa (55 psi).
Check fuel system pressure at the test port on the
fuel rail (Fig. 5) or (Fig. 6).
Fig. 4 Plastic Quick-Connect Fittings
Fig. 5 Fuel Pressure Test PortÐ2.4L
14 - 6 FUEL SYSTEMNS
DESCRIPTION AND OPERATION (Continued)
(1) Remove cap from fuel pressure test port on fuel
rail.
(2) Connect Fuel Pressure Gauge C-4799B to test
port (Fig. 7).
CAUTION: When using the ASD Fuel System Test,
the ASD relay and fuel pump relay remain energized
for 7 minutes or until the test is stopped, or until
the ignition switch is turned to the Off position.
(3) Place the ignition key in the ON position.
Using the DRB scan tool, access ASD Fuel System
Test. The ASD Fuel System Test will activate the fuel
pump and pressurize the system.²If the gauge reading equals 338 kPa (49 psi)
3.3L uses approximately 379 kPa (55 psi) further
testing is not required. If pressure is not correct,
record the pressure.
²If pressure is above specifications, check for a
kinked or restricted fuel return tube (from filter to
pump module). If the fuel return tube is not pinched
or restricted, replace the fuel pressure regulator.
²If fuel pressure is below specifications, refer to
the diagnosis chart for Fuel Pressure Below Specifi-
cations.
(4)Replace Pressure test port cap when fin-
ished doing pressure test.
Fig. 6 Fuel Pressure Test PortÐ3.3/3.8LFig. 7 Checking Fuel Pressure at Fuel Rail
NSFUEL SYSTEM 14 - 7
DIAGNOSIS AND TESTING (Continued)
SERVICE PROCEDURES
FUEL SYSTEM PRESSURE RELEASE
PROCEDUREÐ2.4/3.3/3.8L
WARNING: RELEASE FUEL SYSTEM PRESSURE
BEFORE SERVICING FUEL SYSTEM COMPONENTS.
SERVICE VEHICLES IN WELL VENTILATED AREAS
AND AVOID IGNITION SOURCES. NEVER SMOKE
WHILE SERVICING THE VEHICLE.
(1) Disconnect negative cable from battery.
(2) Remove fuel filler cap.
(3) Remove protective cap from fuel pressure test
port on fuel rail (Fig. 9) or (Fig. 10).
(4) Place open end of fuel pressure release hose,
tool number C-4799-1, into an approved gasoline con-
tainer. Connect other end of hose C-4799-1 to fuel
pressure test port (Fig. 11). Fuel pressure will bleed
off through the hose into the gasoline container. Fuel
gauge C-4799-B contains hose C-4799-1.
(5)Replace Pressure test port cap when fin-
ished doing pressure test.
FUEL SYSTEM PRESSURE RELEASE
PROCEDUREÐ3.0L ENGINE
(1) Remove the Fuel Pump relay from the Power
Distribution Center (PDC). For location of the relay,
refer to the label on the underside of the PDC cover.
(2) Start and run engine it stalls.
(3) Attemp restarting engine until it will no longer
run.(4) Turn ignition key to OFF position.
CAUTION: Steps 1, 2, 3 and 4 must be performed to
relieve high pressure fuel from within the fuel rail.
Do not attempt to use the following steps to relieve
this pressure as excessive fuel will be forced into a
cylinder chamber.
(5) Unplug connector from any injector.
(6) Attach one end of a jumper wire with alligator
clips (18 gauge or smaller) to either injector terminal.
(7) Connect the other end of the jumper wire to
the positive side of the battery.
(8) Connect one end of a second jumper wire to the
remaining injector terminal.
CAUTION: Supplying power to an injector for more
than 4 seconds will permantely damage the injector.
Do not leave the injector connected to power for
more than 4 seconds.
Fig. 9 Fuel Pressure Test PortÐ2.4L
Fig. 10 Fuel Pressure Test PortÐ3.3/3.8L
Fig. 11 Releasing Fuel Pressure
NSFUEL SYSTEM 14 - 11
WARNING: RELEASE FUEL SYSTEM PRESSURE
BEFORE DISCONNECTING QUICK-CONNECT FIT-
TINGS AT FUEL FILTER. REFER TO THE FUEL
PRESSURE RELEASE PROCEDURE.
REMOVAL
(1) Perform fuel system pressure release.
(2) Disconnect quick-connect fittings from fuel
pump module and chassis fuel supply tube. Refer to
Quick-Connect Fittings in this section.
(3) Remove filter retaining screw (Fig. 13) and
remove filter from tank.
INSTALLATION
(1) Install fuel filter to tank.
(2) The fuel supply (to filter) tube, return tube (to
pump module) and fuel supply (to chassis fuel line)
are permanently attached the fuel filter. The ends of
the fuel supply and return tubes have different size
quick-connect fittings.
(3) Apply a light coating of clean 30 weight engine
oil to the fuel filter nipples. Install fuel tubes. Refer
to Fuel Tubes and Quick-Connect Fittings in this sec-
tion.
FUEL PUMP MODULE
WARNING: RELEASE FUEL SYSTEM PRESSURE
BEFORE SERVICING FUEL SYSTEM COMPONENTS.
SERVICE VEHICLES IN WELL VENTILATED AREAS
AND AVOID IGNITION SOURCES. NEVER SMOKE
WHILE SERVICING THE VEHICLE.
WARNING: THE FUEL RESERVOIR OF THE FUEL
PUMP MODULE DOES NOT EMPTY OUT WHEN THE
TANK IS DRAINED. THE FUEL IN THE RESERVOIR
WILL SPILL OUT WHEN THE MODULE IS
REMOVED.
REMOVAL
(1) Remove fuel filler cap and perform Fuel Sys-
tem Pressure Release procedure.
(2) Disconnect negative cable from battery.
(3) Insert fuel siphon hose into fuel filler neck and
push it into the tank.
(4) Drain fuel tank dry into holding tank or a
properly labeledGASOLINEsafety container.
(5) Raise vehicle on hoist.
(6) Use a transmission jack to support the fuel
tank. Remove bolts from fuel tank straps. Lower
tank slightly.
(7) Clean area around fuel tank module and tank
to keep dirt and foreign material out of tank.
(8) Disconnect fuel lines from fuel pump module by
depressing quick connect retainers with thumb and
fore finger (Fig. 14).
(9) Slide fuel pump module electrical connector
lock to unlock.
(10) Push down on connector retainer (Fig. 15) and
pull connector off module.
Fig. 13 Fuel Filter
Fig. 14 Fuel Line Retainers and Pump Connector
Lock
Fig. 15 Pump Module Connector Retainer and Lock
NSFUEL SYSTEM 14 - 13
REMOVAL AND INSTALLATION (Continued)
(11) Using Special Tool 6856, remove plastic lock-
nut counterclockwise to release pump module (Fig.
16).
(12) Carefully remove pump module and O-ring
from tank (Fig. 17).
(13) Discard old O-ring.INSTALLATION
(1) Wipe seal area of tank clean and place a new
O-ring seal in position on pump.
(2) Position fuel pump in tank with locknut.
(3) Tighten locknut to 53 N´m (43 ft. lbs.).
(4) Connect fuel lines.
(5) Plug in electrical connector. Slide connector
lock into position.
(6) Raise fuel tank, install bolts into fuel tank
straps and tighten.
(7) Lower vehicle on hoist.
(8) Connect negative cable from battery.
(9) Fill fuel tank. Check for leaks.
(10) Install fuel filler cap.
FUEL PRESSURE REGULATOR
The fuel pressure regulator is part of the fuel
pump module (Fig. 18). Remove the fuel pump mod-
ule from the fuel tank to access the fuel pressure reg-
ulator.
WARNING: FUEL SYSTEM PRESSURE MUST BE
RELEASED BEFORE SERVICING ANY FUEL SYS-
TEM COMPONENT. PERFORM THE FUEL SYSTEM
PRESSURE RELEASE PROCEDURE.
REMOVAL
(1) Spread tangs on pressure regulator retainer
(Fig. 18).
(2) Pry fuel pressure regulator out of housing.
(3) Ensure both upper and lower O-rings were
removed with regulator.
INSTALLATION
(1) Lightly lubricate the O-rings with clean engine
oil and place them into opening in pump module (Fig.
19).
(2) Push regulator into opening in pump module.
Fig. 16 Fuel Pump Module Lock Nut Removal
Fig. 17 Fuel Pump Module Removal
Fig. 18 Fuel Pressure Regulator
14 - 14 FUEL SYSTEMNS
REMOVAL AND INSTALLATION (Continued)
(7) Install fuel pump module. Refer to Fuel Pump
Module in this section.
FUEL TANK
WARNING: RELEASE FUEL SYSTEM PRESSURE
BEFORE SERVICING FUEL SYSTEM COMPONENTS.
SERVICE VEHICLES IN WELL VENTILATED AREAS
AND AVOID IGNITION SOURCES. NEVER SMOKE
WHILE SERVICING THE VEHICLE.
REMOVAL
(1) Disconnect negative cable from battery.
(2) Remove fuel filler cap and perform Fuel Sys-
tem Pressure Release procedure.
(3) Insert fuel siphon hose into fuel filler neck and
push it into the tank.
(4) Drain fuel tank dry into holding tank or a
properly labeledGASOLINEsafety container.
(5) Raise vehicle on hoist.
(6) Disconnect both the fuel fill and fuel vent rub-
ber hoses at the fuel tank.(7) Disconnect fuel supply lines from the steel sup-
ply line.
The fuel pump module electrical connector
has a retainer that locks it in place.
(8) Slide fuel pump module electrical connector
lock to unlock (Fig. 29).
(9) Push down on connector retainer (Fig. 30) and
pull connector off module.
(10) Use a transmission jack to support fuel tank.
Remove bolts from fuel tank straps.
(11) Lower tank slightly. Carefully remove filler
hose from tank.
(12) Lower the fuel tank. Disconnect pressure
relief/rollover valve hose at the front of tank. Remove
clamp and remove fuel filler tube vent hose. Remove
fuel tank from vehicle.
Fig. 28 Installation Channel
Fuel Tank
Fig. 29 Fuel Line Retainers and Pump Connector
Lock
Fig. 30 Pump Module Connector Retainer and Lock
NSFUEL SYSTEM 14 - 17
REMOVAL AND INSTALLATION (Continued)
INSTALLATION
(1) Position fuel tank on transmission jack. Con-
nect pressure relief/rollover valve hose. Connect fuel
filler tube vent hose and replace clamp.
(2) Raise tank into position and carefully work
filler tube into tank. A light coating of clean engine
oil on the tube end may be used to aid assembly.
(3) Feed filler vent line thru frame rail. Careful
not to cross lines.
(4) Tighten strap bolts to 54 N´m (40 ft. lbs.)
torque. Remove transmission jack.
(5) Tighten filler hose clamp to 3.3 N´m (30 in.
lbs.).
CAUTION: Ensure straps are not twisted or bent
before or after tightening strap nuts.
(6) Connect fuel pump/module electrical connector.
Place retainer in locked position.
(7) Lubricate the fuel supply line with clean 30
weight engine oil, install the quick connect fuel fit-
ting. Refer to Tube/Fitting Assembly in the Fuel
Delivery section of this Group.
(8) Attach filler line to filler tube. Pull on connec-
tor to make sure of connection.
(9) Fill fuel tank, replace cap, and connect battery
negative cable.
CAUTION: When using the ASD Fuel System Test,
the ASD relay and fuel pump relay remain energized
for 7 minutes or until the test is stopped, or until
the ignition switch is turned to the Off position.
(10) Use the DRB scan tool ASD Fuel System Test
to pressurize the fuel system. Check for leaks.
FUEL INJECTOR RAILÐ2.4L
REMOVAL
(1) Perform fuel system pressure release procedure
before servicing or starting repairs.Refer to
Fuel System Pressure Release Procedure in this sec-
tion.
(2) Disconnect negative cable from battery.
(3) Remove air cleaner inlet hose from throttle
body.
(4) Remove throttle cable and speed control cable
(if equipped) from throttle lever.
(5) Remove throttle cables from bracket by com-
pressing retaining tabs.
(6) Remove connector from throttle position sensor.
(7) Remove connector from idle air control motor.
(8) Remove vacuum lines from intake plenum fit-
tings (Fig. 31) and (Fig. 32).(9) Remove connector from intake air temperature
sensor (Fig. 32).
(10) Remove connector from MAP sensor (Fig. 33).
(11) Remove fuel hose quick connect fitting from
the chassis tube (Fig. 34).Refer to Fuel Hoses,
Clamps and Quick Connect Fittings in this Sec-
tion.Place a shop towel under the connections to
absorb any fuel spilled from the fitting.
Fig. 31 Vacuum Fitting on Rear of Intake Manifold
Fig. 32 Electrical and Vacuum Connections
14 - 18 FUEL SYSTEMNS
REMOVAL AND INSTALLATION (Continued)
(4) Install the fuel rail mounting bolts. Tighten
bolts to 22 N´m (200 in. lbs.) torque (Fig. 51).
(5) Install fuel tube retaining bracket screw.
Tighten screw to 4 N´m (35 in. lbs.) torque.
(6) Connect electrical connectors to camshaft posi-
tion sensor and engine coolant temperature sensor.
(7) Remove covering on lower intake manifold and
clean surface.
(8) Place intake manifold gasket on lower mani-
fold. Put upper manifold into place and install bolts
finger tight.
(9) Install the generator bracket to intake mani-
fold bolt and the cylinder head to intake manifold
strut bolts (do not tighten.)(10) Following the tightening sequence in (Fig. 50),
tighten intake manifold bolts to 28 N´m (250 in. lbs.)
torque.
(11) Tighten generator bracket to intake manifold
bolt to 54 N´m (40 ft. lbs.) torque.
(12) Tighten the cylinder head to intake manifold
strut bolts to 54 N´m (40 ft. lbs.) torque.
(13) Connect ground strap and MAP sensor electri-
cal connector.
(14) Connect vacuum harness to intake plenum.
Connect PCV system hoses.
(15) Using a new gasket, connect the EGR tube to
the intake manifold plenum. Tighten screws to 22
N´m (200 in. lbs.) torque.
(16) Connect electrical connectors to the TPS and
idle air control motor.
(17) Connect vacuum harness to throttle body.
(18) Install the direct ignition system (DIS) coils.
Tighten fasteners to 12 N´m (105 in. lbs.) torque.
(19) Install fuel hose quick connector fitting to
chassis tubes.Refer to Fuel Hoses, Clamps and
Quick Connect Fittings in this Section.Push the
fitting onto the chassis tube until it clicks into place.
Pull on the fitting to ensure complete insertion.
(20) Install throttle cable and speed control cable
(if equipped).
(21) Install air inlet resonator.
(22) Connect negative cable to battery.
CAUTION: When using the ASD Fuel System Test,
the ASD relay and fuel pump relay remain energized
for 7 minutes or until the test is stopped, or until
the ignition switch is turned to the Off position.
(23) With the ignition key in ON position, access
the DRB scan tool ASD Fuel System Test to pressur-
ize the fuel system. Check for leaks.
FUEL INJECTORÐ2.4L
The fuel rail must be removed first. Refer to Fuel
Injector Rail Removal in this section.
REMOVAL
(1) Disconnect injector wiring connector from injec-
tor.
(2) Position fuel rail assembly so that the fuel
injectors are easily accessible (Fig. 54).
(3) Rotate injector and pull injector out of fuel rail.
The clip will stay on the injector.
(4) Check injector O-ring for damage. If O-ring is
damaged, it must be replaced. If injector is reused, a
protective cap must be installed on the injector tip to
prevent damage. Replace the injector clip if it is dam-
aged.
(5) Repeat for remaining injectors.
Fig. 52 Camshaft Position Sensor Connector
Fig. 53 Fuel Rail Removal
14 - 24 FUEL SYSTEMNS
REMOVAL AND INSTALLATION (Continued)