Gas gauge JEEP GRAND CHEROKEE 2002 WJ / 2.G Owner's Guide

FUEL DELIVERY
DESCRIPTION
The fuel delivery system consists of:
²the fuel pump module containing the electric
fuel pump, fuel gauge sending unit (fuel level sensor)
and a separate fuel filter located at bottom of pump
module
²a separate combination fuel filter/fuel pressure
regulator
²fuel tubes/lines/hoses
²quick-connect fittings
²fuel injector rail
²fuel injectors
²fuel tank
²fuel tank filler/vent tube assembly
²fuel tank filler tube cap
²accelerator pedal
²throttle cable
OPERATION
The fuel tank assembly consists of: the fuel tank,
fuel tank shield, fuel tank straps, fuel pump module
assembly, fuel pump module locknut/gasket, and fuel
tank check valve (refer to Emission Control System
for fuel tank check valve information).
A fuel filler/vent tube assembly using a pressure/
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 fuel system is the
evaporation control system. This is designed to
reduce the emission of fuel vapors into the atmo-
sphere. The description and function of the Evapora-
tive 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 service. They do not require normal sched-
uled maintenance. Filters should only be replaced if
a diagnostic procedure indicates to do so.
DIAGNOSIS AND TESTING
FUEL PRESSURE LEAK DOWN TEST
Use this test in conjunction with the Fuel Pump
Pressure Test and Fuel Pump Capacity Test.
Check Valve Operation:The electric fuel pump
outlet contains a one-way check valve to prevent fuel
flow back into the tank and to maintain fuel supply
line pressure (engine warm) when pump is not oper-
ational. It is also used to keep the fuel supply line
full of gasoline when pump is not operational. After
the vehicle has cooled down, fuel pressure may drop
to 0 psi (cold fluid contracts), but liquid gasoline willremain in fuel supply line between the check valve
and fuel injectors.Fuel pressure that has
dropped to 0 psi on a cooled down vehicle
(engine off) is a normal condition.When the elec-
tric fuel pump is activated, fuel pressure should
immediately(1±2 seconds) rise to specification.
Abnormally long periods of cranking to restart a
hotengine that has been shut down for a short
period of time may be caused by:
²Fuel pressure bleeding past a fuel injector(s).
²Fuel pressure bleeding past the check valve in
the fuel pump module.
²A defective fuel filter/pressure regulator.
Two #6539, 5/16º, Fuel Line Pressure Test Adapter
Hose Tools are required for the following tests.
(1) Release fuel system pressure. Refer to Fuel
Pressure Release Procedure.
(2) Raise vehicle.
Fuel Line Identification:The fuel filter/pressure
regulator is located in front of the fuel tank and
above the rear axle. It is transversely mounted to a
chassis crossmember (left-to-right). The filter/regula-
tor is equipped with 3 fuel line fittings (2 at one end
and 1 at the other end). The single fitting facing the
left side of the vehicle is the supply line to the fuel
rail (Fig. 1) . The 2 fittings facing the right side of
the vehicle are connected to the fuel tank. Of these 2
fittings, the fitting towards thefrontis used for fuel
return to the fuel tank. The fitting towards therear
is a pressure line. Thisrearfitting must be discon-
nected for the following step.
(3) See previous step. Disconnect fuel pressure line
atrearof filter/regulator. This is a 5/169quick-con-
nect fitting (Fig. 1) . Refer to Quick-Connect Fittings
for procedures.
(4) Obtain correct Fuel Line Pressure Test Adapter
Hose Tool # 6539 for 5/16º fuel lines. Connect one
end of this Special Tool into the disconnected fuel
pressure line. Connect the other end of the Tool into
fitting on filter/regulator.
(5) Lower vehicle.
(6) Disconnect the fuel inlet line at fuel rail. Refer
to Quick-Connect Fittings for procedures. On some
engines, air cleaner housing removal may be neces-
sary before fuel line disconnection.
(7) Obtain a second Fuel Line Pressure Test
Adapter Hose Tool # 6539 for 5/16º fuel lines. Con-
nect this tool between disconnected fuel line and fuel
rail (Fig. 2) .
(8) Connect the 0-414 kPa (0-60 psi) fuel pressure
test gauge (from Gauge Set 5069) to the test port on
the appropriate Adaptor Tool.NOTE: The DRB III
Scan Tool along with the PEP module, the 500
psi pressure transducer, and the transducer-to-
test port adapter may also be used in place of
the fuel pressure gauge.
14 - 2 FUEL DELIVERYWJ

(19) Disconnect test leads from relay cavities
immediately after testing.
FUEL PUMP PRESSURE TEST
Use this test in conjunction with other fuel system
tests. Refer to the Fuel Pump Capacity Test, Fuel
Pressure Leak Down Test and Fuel Pump Amperage
Test.
Check Valve Operation:The electric fuel pump
outlet contains a one-way check valve to prevent fuel
flow back into the tank and to maintain fuel supply
line pressure (engine warm) when pump is not oper-
ational. It is also used to keep the fuel supply line
full of gasoline when pump is not operational. After
the vehicle has cooled down, fuel pressure may drop
to 0 psi (cold fluid contracts), but liquid gasoline will
remain in fuel supply line between the check valve
and fuel injectors.Fuel pressure that has
dropped to 0 psi on a cooled down vehicle
(engine off) is a normal condition.When the elec-
tric fuel pump is activated, fuel pressure should
immediately(1±2 seconds) rise to specification.
The fuel system is equipped with a combination
fuel filter/fuel pressure regulator. The fuel pressure
regulator is not controlled by engine vacuum.
WARNING: THE FUEL SYSTEM IS UNDER CON-
STANT FUEL PRESSURE EVEN WITH THE ENGINE
OFF. BEFORE DISCONNECTING FUEL LINE AT
FUEL RAIL, THIS PRESSURE MUST BE RELEASED.REFER TO THE FUEL SYSTEM PRESSURE
RELEASE PROCEDURE.
(1) Remove pressure test port cap at fuel rail test
port (Fig. 12) or (Fig. 13) . Connect 0±414 kPa (0-60
psi) fuel pressure gauge (from gauge set 5069) to test
port pressure fitting on fuel rail (Fig. 14) .The DRB
III Scan Tool along with the PEP module, the
500 psi pressure transducer, and the transduc-
er-to-test port adapter may also be used in
place of the fuel pressure gauge.
(2) Start and warm engine and note pressure
gauge reading. The DRB scan tool may also be used
to power fuel pump. Fuel pressure should be 339 kPa
  34 kPa (49.2 psi   5 psi) at idle.
(3) If engine runs, but pressure is below 44.2 psi,
determine if fuel pump or filter/regulator is defective.
Proceed to next step:
(a) Check for a kinked fuel supply line some-
where between fuel rail and fuel pump module.
Fig. 11 FUEL PUMP RELAY - TYPE 3
TERMINAL LEGEND
NUMBER IDENTIFICATION
1 COIL BATTERY
2 COIL GROUND
3 COMMON FEED
4 NORMALLY CLOSED
5 NORMALLY OPEN
Fig. 12 Test Port Cap LocationÐ4.0L Engine
1 - INJ. #1
2 - INJ. #2
3 - INJ. #3
4 - INJ. #4
5 - INJ. #5
6 - INJ. #6
7 - FUEL INJECTOR RAIL
8 - FUEL DAMPER
9 - PRESSURE TEST PORT CAP
10 - MOUNTING BOLTS (4)
11 - QUICK-CONNECT FITTING
WJFUEL DELIVERY 14 - 11
FUEL PUMP (Continued)

(e) Use DRB scan tool to power fuel pump. If
pressure is now within specifications, replace fuel
filter/fuel pressure regulator.
(f) If pressure is still low, replace fuel pump
module.
(4) If operating pressure is above 54.2 psi, electric
fuel pump is OK, but fuel pressure regulator is defec-
tive. Replace fuel filter/fuel pressure regulator.
(5) Install test port cap to fuel rail test port.
FUEL PUMP MODULE
DESCRIPTION
The fuel pump module is installed in the top of the
fuel tank (Fig. 16). The fuel pump module (Fig. 17)
contains the following components:
²A separate fuel pick-up filter (strainer)
²An electric fuel pump
²A threaded locknut to retain module to tank
²A gasket between tank flange and module
²Fuel gauge sending unit (fuel level sensor)²Fuel supply tube (line) connection
²Fuel return tube (line) connection
The fuel gauge sending unit and pick-up filter may
be serviced separately. If the electrical fuel pump
requires service, the entire fuel pump module must
be replaced.
OPERATION
Refer to Fuel Pump, Fuel Filter/Fuel Pressure Reg-
ulator and Fuel Gauge Sending Unit.
REMOVAL
Fuel tank removal will be necessary for fuel pump
module removal.
WARNING: THE FUEL SYSTEM IS UNDER A CON-
STANT PRESSURE (EVEN WITH THE ENGINE OFF).
BEFORE SERVICING FUEL PUMP MODULE, FUEL
SYSTEM PRESSURE MUST BE RELEASED.
(1) Perform Fuel System Pressure Release Proce-
dure.
Fig. 16 FUEL TANK AND COMPONENTS
1 - FUEL PUMP MODULE 9 - TANK SUPPORT BRACKET (SMALL/FRONT)
2 - MODULE LOCK RING 10 - MODULE PIGTAIL HARNESS
3 - TANK SUPPORT BRACKETS (REAR) 11 - FUEL SUPPLY (PRESSURE) LINE
4 - CHECK VALVE 12 - FUEL RETURN LINE
5 - FUEL FILL HOSE 13 - SKID PLATE
6 - ORVR COMPONENTS 14 - TANK STRAPS (2)
7 - ORVR CONTROL VALVE 15 - FUEL TANK
8 - CONTROL VALVE LOCK RING
WJFUEL DELIVERY 14 - 13
FUEL PUMP (Continued)

(2) Drain fuel tank and remove tank. Refer to Fuel
Tank Removal/Installation.
(3) Thoroughly wash and clean area around pump
module to prevent contaminants from entering tank.
(4) Disconnect fuel return and pressure lines from
fuel pump module fittings (Fig. 16). Refer to Quick-
Connect Fittings for procedures.
(5) The plastic fuel pump module locknut is
threaded onto fuel tank (Fig. 16). Install Special Tool
6856 to fuel pump module locknut and remove lock-
nut (Fig. 18). The fuel pump module will spring up
slightly after locknut is removed.
(6) Remove module from fuel tank.
INSTALLATION
Fuel tank removal will be necessary for fuel pump
module removal.
CAUTION: Whenever fuel pump module is serviced,
module gasket must be replaced.
(1) Thoroughly clean locknut threads and mating
fuel tank threads. Use a soap/water solution. Do not
use carburetor cleaner to clean threads.
(2) Using new gasket, position fuel pump module
into opening in fuel tank.
(3) Apply clean water to locknut threads.(4) Position locknut over top of fuel pump module.
(5) Rotate module until indexing arrow at top of
module (Fig. 19)is pointed toward rear of vehicle.
Align arrow to tick mark on top of fuel tank.This
step must be done to prevent float/float rod
assembly from contacting sides of fuel tank.
(6) Install Special Tool 6856 to locknut.
(7) Tighten locknut to 74 N´m (55 ft. lbs.) torque.
Fig. 17 FUEL PUMP MODULE
1 - FUEL PUMP MODULE
2 - FUEL GAUGE FLOAT
3 - ELECTRIC FUEL PUMP
4 - INLET FILTER
5 - FUEL GAUGE SENDING UNIT
6 - PIGTAIL HARNESS
Fig. 18 LOCKNUT REMOVAL/INSTALLATION -
TYPICAL
1 - SPECIAL TOOL 6856
2 - LOCKNUT
Fig. 19 FUEL PUMP MODULE INDEXING ARROW
1 - FUEL PUMP MODULE
2 - INDEXING ARROW
3 - FUEL SUPPLY (PRESSURE) FITTING
4 - FUEL RETURN FITTING
14 - 14 FUEL DELIVERYWJ
FUEL PUMP MODULE (Continued)

NOTE: The reaction plate is thinner than the pres-
sure plate in a 42RE transmission.
(5) Install first clutch disc followed by first clutch
plate. Then install remaining clutch discs and plates
in same order.
(6) Install clutch pack pressure plate.
(7) Install clutch pack wire-type retaining ring
(Fig. 182).
INTERMEDIATE SHAFT SPACER SELECTION
(1) Place overdrive unit in vertical position. Mount
it on blocks, or in workbench with appropriate size
mounting hole cut into it. Be sure unit is facing
upward for access to direct clutch hub. Also be sure
output shaft is not loaded and internal components
are moved rearward for accurate measurement.
(2) Determine correct thickness intermediate shaft
spacer as follows:
(a) Insert Special Tool 6312 through sun gear,
planetary gear and into pilot bushing in output
shaft. Be sure tool bottoms against planetary
shoulder.
(b) Position Gauge Tool 6311 across face of over-
drive case (Fig. 183). Then position Dial Caliper
C-4962 over gauge tool.
(c) Extend sliding scale of dial caliper downward
through gauge tool slot until scale contacts end of
Gauge Alignment Tool 6312. Lock scale in place.
Remove dial caliper tool and note distance mea-
sured (Fig. 183).
(d) Select proper thickness end play spacer from
spacer chart based on distance measured (Fig.
184).
(e) Remove Gauge Alignment Tool 6312.
Fig. 177 Seating Locating Ring In Rear Bearing
1 - EXPAND BEARING LOCATING RING WITH SNAP-RING
PLIERS
2 - ACCESS HOLE
Fig. 178 Locating Ring Access Cover And Gasket
Installation
1 - TORX SCREWDRIVER (T25)
2 - ACCESS COVER SCREWS
Fig. 179 Overdrive Clutch Reaction Ring Installation
1 - REACTION RING
2 - CLUTCH HUB
Fig. 180 Overdrive Clutch Wave Spring Installation
1 - WAVE SPRING
21 - 102 AUTOMATIC TRANSMISSION - 42REWJ
OVERDRIVE UNIT (Continued)