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

INTAKE/EXHAUST VALVES &
SEATS
DESCRIPTION
The valves are made of heat resistant steel and
have chrome plated stems to prevent scuffing. Each
valve is actuated by a roller rocker arm which pivots
on a stationary lash adjuster. All valves use three
bead lock keepers to retain the springs and promote
valve rotation.
STANDARD PROCEDUREÐREFACING
NOTE: Valve seats that are worn or burned can be
reworked, provided that correct angle and seat
width are maintained. Otherwise the cylinder head
must be replaced.
NOTE: When refacing valves and valve seats, it is
important that the correct size valve guide pilot be
used for reseating stones. A true and complete sur-
face must be obtained.
(1) Using a suitable dial indicator measure the
center of the valve seat Total run out must not
exceed 0.051 mm (0.002 in).
(2) Apply a small amount of Prussian blue to the
valve seat, insert the valve into the cylinder head,
while applying light pressure on the valve rotate the
valve. Remove the valve and examine the valve face.
If the blue is transferred below the top edge of the
valve face, lower the valve seat using a 15 degree
stone. If the blue is transferred to the bottom edge of
the valve face, raise the valve seat using a 65 degree
stone.
(3) When the seat is properly positioned the width
of the intake seat must be 1.75 ± 2.36 mm (0.0689 ±
0.0928 in.) and the exhaust seat must be 1.71 ± 2.32
mm (0.0673 ± 0.0911 in.).
(4) Check the valve spring installed height after
refacing the valve and seat. The installed height for
both intake and exhaust valve springs must not
exceed 41.44 mm (1.6315 in.).
(5) The valve seat and valve face must maintain a
face angle of 44.5 ± 45 degrees angle (Fig. 23).
REMOVAL
NOTE: The cylinder heads must be removed in
order to preform this procedure.
(1) Remove rocker arms and lash adjusters. Refer
to procedures in this section (Fig. 24).
(2) Remove the camshaft bearing caps and the
camshaft.
Fig. 23 Valve Assembly Configuration
1 - VALVE LOCKS (3±BEAD)
2 - RETAINER
3 - VALVE STEM OIL SEAL
4 - INTAKE VALVE
5 - EXHAUST VALVE
6 - VALVE SPRING
Fig. 24 Rocker Arm Removal
1 - CAMSHAFT
2 - SPECIAL TOOL 8516
9 - 94 ENGINE - 4.7LWJ

NOTE: All eight valve springs and valves are
removed in the same manner; this procedure only
covers one valve and valve spring.
(3) Using Special Tool C-3422±B or C-3422±C
Valve Spring Compressor and Special tool 8519
Adapter, compress the valve spring.
NOTE: It may be necessary to tap the top of the
valve spring to loosen the spring retainers locks
enough to be removed.
(4) Remove the two spring retainer lock halves.
NOTE: the valve spring is under tension use care
when releasing the valve spring compressor.
(5) Remove the valve spring compressor.
(6) Remove the spring retainer, and the spring.
NOTE: Check for sharp edges on the keeper
grooves. Remove any burrs from the valve stem
before removing the valve from the cylinder head.
(7) Remove the valve from the cylinder head.
NOTE: The valve stem seals are common between
intake and exhaust.
(8) Remove the valve stem seal. Mark the valve for
proper installation.
TESTING VALVE SPRINGS
NOTE: Whenever the valves are removed from the
cylinder head it is recommended that the valve
springs be inspected and tested for reuse.
Inspect the valve springs for physical signs of wear
or damage. Turn table of tool C-647 until surface is
in line with the 40.69 mm (1.602 in.) mark on the
threaded stud and the zero mark on the front. Place
spring over the stud on the table and lift compress-
ing lever to set tone device. Pull on torque wrench
until Ping is heard. Take reading on torque wrench
at this instant. Multiply this reading by two. This
will give the spring load at test length. Fractional
measurements are indicated on the table for finer
adjustments. Refer to Specifications Section to obtain
specified height and allowable tensions. Replace any
springs that do not meet specifications. (Fig. 25)
INSTALLATION
(1) coat the valve stem with clean engine oil and
insert it into the cylinder head.
(2) Install the valve stem seal. make sure the seal
is fully seated and that the garter spring at the top
of the seal is intact.
(3) Install the spring and the spring retainer (Fig.
26).
(4) Using the valve spring compressor, compress
the spring and install the two valve spring retainer
halves.
(5) Release the valve spring compressor and make
sure the two spring retainer halves and the spring
retainer are fully seated.
(6) lubricate the camshaft journal with clean
engine oil then Position the camshaft (with the
sprocket dowel on the left camshaft at 11 o'clock and
the right camshaft at 12 o'clock), then position the
camshaft bearing caps.
(7) Install the camshaft bearing cap retaining
bolts. Tighten the bolts 9±13 N´m (100 in. lbs.) in
1¤2
turn increments in the sequence shown (Fig. 27).
(8) Position the hydraulic lash adjusters and
rocker arms (Fig. 24).
Fig. 25 Testing Valve Springs
1 - SPECIAL TOOL C-647
WJENGINE - 4.7L 9 - 95
INTAKE/EXHAUST VALVES & SEATS (Continued)

STANDARD PROCEDUREÐREFACING
NOTE: Valve seats that are worn or burned can be
reworked, provided that correct angle and seat
width are maintained. Otherwise the cylinder head
must be replaced.
NOTE: When refacing valves and valve seats, it is
important that the correct size valve guide pilot be
used for reseating stones. A true and complete sur-
face must be obtained.
(1) Using a suitable dial indicator measure the
center of the valve seat Total run out must not
exceed 0.051 mm (0.002 in).
(2) Apply a small amount of Prussian blue to the
valve seat, insert the valve into the cylinder head,
while applying light pressure on the valve rotate the
valve. Remove the valve and examine the valve face.
If the blue is transferred below the top edge of the
valve face, lower the valve seat using a 15 degree
stone. If the blue is transferred to the bottom edge of
the valve face, raise the valve seat using a 65 degree
stone.
(3) When the seat is properly positioned the width
of the intake seat must be 1.75 ± 2.36 mm (0.0689 ±
0.0928 in.) and the exhaust seat must be 1.71 ± 2.32
mm (0.0673 ± 0.0911 in.).
(4) Check the valve spring installed height after
refacing the valve and seat. The installed height for
both intake and exhaust valve springs must not
exceed 41.44 mm (1.6315 in.).
(5) The valve seat and valve face must maintain a
face angle of 44.5 ± 45 degrees angle (Fig. 39).
REMOVAL
NOTE: The cylinder heads must be removed in
order to preform this procedure.
(1) Remove rocker arms and lash adjusters. Refer
to procedures in this section (Fig. 40).
(2) Remove the camshaft bearing caps and the
camshaft.
NOTE: All eight valve springs and valves are
removed in the same manner; this procedure only
covers one valve and valve spring.
(3) Using Special Tool C-3422±B or C-3422±C
Valve Spring Compressor and Special tool 8519
Adapter, compress the valve spring.
NOTE: It may be necessary to tap the top of the
valve spring to loosen the spring retainers locks
enough to be removed.
Fig. 39 Valve Assembly Configuration
1 - VALVE LOCKS (3±BEAD)
2 - RETAINER
3 - VALVE STEM OIL SEAL
4 - INTAKE VALVE
5 - EXHAUST VALVE
6 - VALVE SPRING
Fig. 40 Rocker Arm Removal
1 - CAMSHAFT
2 - SPECIAL TOOL 8516
WJENGINE - 4.7L 9 - 105
INTAKE/EXHAUST VALVES & SEATS (Continued)

(4) Remove the two spring retainer lock halves.
NOTE: the valve spring is under tension use care
when releasing the valve spring compressor.
(5) Remove the valve spring compressor.
(6) Remove the spring retainer, and the spring.
NOTE: Check for sharp edges on the keeper
grooves. Remove any burrs from the valve stem
before removing the valve from the cylinder head.
(7) Remove the valve from the cylinder head.
NOTE: The valve stem seals are common between
intake and exhaust.
(8) Remove the valve stem seal. Mark the valve for
proper installation.
TESTING VALVE SPRINGS
NOTE: Whenever the valves are removed from the
cylinder head it is recommended that the valve
springs be inspected and tested for reuse.
Inspect the valve springs for physical signs of wear
or damage. Turn table of tool C-647 until surface is
in line with the 40.69 mm (1.602 in.) mark on the
threaded stud and the zero mark on the front. Place
spring over the stud on the table and lift compress-
ing lever to set tone device. Pull on torque wrench
until Ping is heard. Take reading on torque wrench
at this instant. Multiply this reading by two. This
will give the spring load at test length. Fractional
measurements are indicated on the table for finer
adjustments. Refer to Specifications Section to obtain
specified height and allowable tensions. Replace any
springs that do not meet specifications. (Fig. 41)
INSTALLATION
(1) coat the valve stem with clean engine oil and
insert it into the cylinder head.
(2) Install the valve stem seal. make sure the seal
is fully seated and that the garter spring at the top
of the seal is intact.
(3) Install the spring and the spring retainer (Fig.
42).
(4) Using the valve spring compressor, compress
the spring and install the two valve spring retainer
halves.
(5) Release the valve spring compressor and make
sure the two spring retainer halves and the spring
retainer are fully seated.(6) lubricate the camshaft journal with clean
engine oil then Position the camshaft (with the
sprocket dowel on the left camshaft at 11 o'clock and
the right camshaft at 12 o'clock), then position the
camshaft bearing caps.
Fig. 41 Testing Valve Springs
1 - SPECIAL TOOL C-647
Fig. 42 Valve Assembly Configuration
1 - VALVE LOCKS (3±BEAD)
2 - RETAINER
3 - VALVE STEM OIL SEAL
4 - INTAKE VALVE
5 - EXHAUST VALVE
6 - VALVE SPRING
9 - 106 ENGINE - 4.7LWJ
INTAKE/EXHAUST VALVES & SEATS (Continued)

The other two heater elements (downstream sen-
sors 1/2 and 2/2) are controlled by the downstream
heater relay through output signals from the PCM.
To avoid a large simultaneous current surge, power
is delayed to the 2 downstream heater elements by
the PCM for approximately 2 seconds.
REMOVAL
(1) Remove PDC cover.
(2) Remove relay from PDC.
(3) Check condition of relay terminals and PDC
connector terminals for damage or corrosion. Repair
if necessary before installing relay.
(4) Check for pin height (pin height should be the
same for all terminals within the PDC connector).
Repair if necessary before installing relay.
INSTALLATION
(1) Install relay to PDC.
(2) Install cover to PDC.
O2S SENSOR
DESCRIPTION
The Oxygen Sensors (O2S) are attached to, and
protrude into the vehicle exhaust system. Depending
on the emission package, the vehicle may use a total
of either 2 or 4 sensors.
Federal Emissions Package:Two sensors are
used: upstream (referred to as 1/1) and downstream
(referred to as 1/2). With this emission package, the
upstream sensor (1/1) is located just before the main
catalytic convertor. The downstream sensor (1/2) is
located just after the main catalytic convertor.
4.7L V-8 With California Emissions Package:
On this emissions package, 4 sensors are used: 2
upstream (referred to as 1/1 and 2/1) and 2 down-
stream (referred to as 1/2 and 2/2). With this emis-
sion package, the right upstream sensor (2/1) is
located in the right exhaust downpipe just before the
mini-catalytic convertor. The left upstream sensor
(1/1) is located in the left exhaust downpipe just
before the mini-catalytic convertor. The right down-
stream sensor (2/2) is located in the right exhaust
downpipe just after the mini-catalytic convertor, and
before the main catalytic convertor. The left down-
stream sensor (1/2) is located in the left exhaust
downpipe just after the mini-catalytic convertor, and
before the main catalytic convertor.
4.0L 6±Cylinder With California Emissions
Package:On this emissions package, 4 sensors are
used: 2 upstream (referred to as 1/1 and 2/1) and 2
downstream (referred to as 1/2 and 2/2). With this
emission package, the rear/upper upstream sensor
(2/1) is located in the exhaust downpipe just beforethe rear mini-catalytic convertor. The front/upper
upstream sensor (1/1) is located in the exhaust down-
pipe just before the front mini-catalytic convertor.
The rear/lower downstream sensor (2/2) is located in
the exhaust downpipe just after the rear mini-cata-
lytic convertor, and before the main catalytic conver-
tor. The front/lower downstream sensor (1/2) is
located in the exhaust downpipe just after the front
mini-catalytic convertor, and before the main cata-
lytic convertor.
OPERATION
An O2 sensor is a galvanic battery that provides
the PCM with a voltage signal (0-1 volt) inversely
proportional to the amount of oxygen in the exhaust.
In other words, if the oxygen content is low, the volt-
age output is high; if the oxygen content is high the
output voltage is low. The PCM uses this information
to adjust injector pulse-width to achieve the
14.7±to±1 air/fuel ratio necessary for proper engine
operation and to control emissions.
The O2 sensor must have a source of oxygen from
outside of the exhaust stream for comparison. Cur-
rent O2 sensors receive their fresh oxygen (outside
air) supply through the O2 sensor case housing.
Four wires (circuits) are used on each O2 sensor: a
12±volt feed circuit for the sensor heating element; a
ground circuit for the heater element; a low-noise
sensor return circuit to the PCM, and an input cir-
cuit from the sensor back to the PCM to detect sen-
sor operation.
Oxygen Sensor Heaters/Heater Relays:
Depending on the emissions package, the heating ele-
ments within the sensors will be supplied voltage
from either the ASD relay, or 2 separate oxygen sen-
sor relays. Refer to Wiring Diagrams to determine
which relays are used.
The O2 sensor uses a Positive Thermal Co-efficient
(PTC) heater element. As temperature increases,
resistance increases. At ambient temperatures
around 70ÉF, the resistance of the heating element is
approximately 4.5 ohms on 4.0L engines. It is
approximately 13.5 ohms on the 4.7L engine. As the
sensor's temperature increases, resistance in the
heater element increases. This allows the heater to
maintain the optimum operating temperature of
approximately 930É-1100ÉF (500É-600É C). Although
the sensors operate the same, there are physical dif-
ferences, due to the environment that they operate
in, that keep them from being interchangeable.
Maintaining correct sensor temperature at all
times allows the system to enter into closed loop
operation sooner. Also, it allows the system to remain
in closed loop operation during periods of extended
idle.
14 - 50 FUEL INJECTIONWJ
O2S HEATER RELAY (Continued)

(6) Remove bolts attaching hinges to hood.
(7) With the aid of a helper, remove hood from
vehicle.
INSTALLATION
(1) Position hood on hinges.
(2) Install bolts finger-tight.
(3) Align hinges with installation reference marks
and tighten bolts.
(4) Install hood support prop rods.
(5) Connect underhood lamp connector.
(6) Inspect hood for proper alignment and adjust
as necessary.
ADJUSTMENTS
HOOD ADJUSTMENT
The hood attaching holes are enlarged to aid front,
back and side to side adjustment.
(1) If hood is low in relation to cowl panel, insert
shims between hinge and hood.
(2) Adjust hood bumper in or out to adjust hood-
to-fender height alignment.
(3) Adjust the hood latch as necessary. Tighten the
nuts to 11N´m (8 ft. lbs.).
(4) Align the latch striker so that striker enters
the latch squarely and without binding.
INSULATION
REMOVAL
(1) Raise the hood.
(2) Remove the insulation panel fasteners.
(3) Remove the hood insulation panel.
INSTALLATION
(1) Position the insulation panel on the underside
of the hood.
(2) Install the insulation panel fasteners.
(3) Close the hood.
LATCH
REMOVAL
(1) Remove nuts attaching latch to radiator cross-
member support (Fig. 2).
(2) Disconnect hood release cable from latch.
(3) Separate latch from vehicle.
INSTALLATION
(1) Connect latch release cable to latch.
(2) Position latch on radiator crossmember sup-
port.
(3) Install nuts attaching latch to radiator cross-
member support. Tighten nuts to 11 N´m (8 ft. lbs.)
torque (Fig. 2).
Fig. 2 Hood Latch
1 - HOOD RELEASE CABLE
2-LATCH
3 - BUMPER
23 - 34 HOODWJ
HOOD (Continued)

ASSIST HANDLE
REMOVAL
(1) Remove the screws holding the assist handle to
the roof panel.
(2) Remove the assist handle from the roof panel.
INSTALLATION
(1) Align the assist handle with the screw holes in
the roof panel.
(2) Install the screws holding the assist handle to
the roof panel.
B-PILLAR LOWER TRIM
REMOVAL
(1) Remove front door sill trim (Refer to 23 -
BODY/INTERIOR/DOOR SILL TRIM - REMOVAL).
(2) Remove front seat shoulder belt anchor bolt.(3) Remove front seat shoulder belt height adjust-
ment knob and turning loop.
(4) Remove screw attaching front of quarter panel
trim to floor.
(5) Remove screws attaching front and rear of
B-pillar lower trim to floor.
(6) Remove screw attaching B-pillar lower trim to
B-pillar (Fig. 2).
(7) Grasp B-pillar lower trim and pull outward to
separate from B-pillar.
(8) Route seat/shoulder belt through access slot in
B-pillar lower trim.
(9) Separate B-pillar lower trim from B-pillar.
INSTALLATION
(1) Position B-pillar lower trim panel at B-pillar
(Fig. 2).
(2) Route seat/shoulder belt through access slot in
B-pillar lower trim.
(3) Press B-pillar lower trim onto B-pillar.
Fig. 2 B-Pillar Trim Panel
1 - B-PILLAR UPPER TRIM
2 - ACCESS COVER
3 - B-PILLAR LOWER TRIM
4 - PLASTIC NUT
5 - COWL LOWER TRIM6 - CLIP
7 - SCUFF PLATE
8 - SILL TRIM
9 - A-PILLAR TRIM
23 - 70 INTERIORWJ

(4) Install screw attaching B-pillar lower trim to
B-pillar.
(5) Install screw attaching front of B-pillar lower
trim to floor.
(6) Install screw attaching front of quarter panel
trim to floor.
(7) Install front seat shoulder belt anchor bolt.
(8) Install front seat shoulder belt height adjust-
ment knob and turning loop.
(9) Install front door sill trim (Refer to 23 - BODY/
INTERIOR/DOOR SILL TRIM - INSTALLATION).
B-PILLAR UPPER TRIM
REMOVAL
(1) Remove shoulder belt height adjustment knob.
(2) Remove front seat belt turning loop.
(3) Remove the screw attaching lower B pillar
trim.
(4) Pull lower B pillar trim out far enough to
remove upper trim panel.
(5) Grasp upper B-pillar trim and pull outward to
detach from B-pillar (Fig. 2).
INSTALLATION
(1) Position trim panel on B-pillar (Fig. 2).
(2) Ensure trim panel covers inner edge of door
opening weatherstrip and press inward to seat.
(3) Install screw attaching lower B pillar trim
panel.
(4) Install front seat belt turning loop.
(5) Install shoulder belt height adjustment knob.
CARPETS AND FLOOR MATS
REMOVAL
REMOVAL - FRONT CARPET
(1) Remove door sill trim (Refer to 23 - BODY/IN-
TERIOR/DOOR SILL TRIM - REMOVAL).
(2) Remove the B-pillar lower trim, refer to (Refer
to 23 - BODY/INTERIOR/B-PILLAR LOWER TRIM -
REMOVAL).
(3) Remove front seats (Refer to 23 - BODY/
SEATS/SEAT - REMOVAL).
(4) Remove the rear seats lower cushions (Refer to
23 - BODY/SEATS/SEAT CUSHION - REMOVAL).
(5) Remove center floor console (Refer to 23 -
BODY/INTERIOR/FLOOR CONSOLE - REMOVAL).
(6) Remove any other interfering trim or molding.
(7) Lift carpet and mat from floor panel.
REMOVAL - CARGO AREA CARPET
(1) Lift tailgate.
(2) Fold rear seat cushions forward.
(3) Remove rear seat backs (Refer to 23 - BODY/
SEATS/REAR SEAT BACK - REMOVAL).
(4) Remove the rear shoulder belts (Refer to 8 -
ELECTRICAL/RESTRAINTS/REAR SEAT BELT &
RETRACTOR - REMOVAL).
(5) Remove the retractable security cargo cover
assembly.
(6) Remove the spare tire cover.
(7) Remove the rear cargo tie down footman loops.
The side mounted footman loops are retained by
screws. The floor footman loops are riveted (Fig. 3).
(8) Remove the C pillar trim (Refer to 23 - BODY/
INTERIOR/C-PILLAR TRIM - REMOVAL).
(9) Remove the CD changer, if equipped (Refer to 8
- ELECTRICAL/AUDIO/CD CHANGER - REMOV-
AL).
(10) Remove the Infinity amp, if equipped (Refer to
8 - ELECTRICAL/AUDIO/AMPLIFIER - REMOVAL).
(11) Lift the carpet.
INSTALLATION
INSTALLATION - FRONT CARPET
(1) Carefully lay the carpet and mat on the floor
panel. Align the carpet to allow installation of the
components fastened to the floor panel.
(2) Install the center console (Refer to 23 - BODY/
INTERIOR/FLOOR CONSOLE - INSTALLATION).
(3) Install the front seats (Refer to 23 - BODY/
SEATS/SEAT - INSTALLATION).
(4) Install the rear seat cushions (Refer to 23 -
BODY/SEATS/SEAT CUSHION - INSTALLATION).
Fig. 3 Cargo Area Carpet
1 - CARGO AREA CARPET
2 - RIVET
3 - CARGO TIE-DOWN LOOP
WJINTERIOR 23 - 71
B-PILLAR LOWER TRIM (Continued)

(5) Install the lower B pillar trim (Refer to 23 -
BODY/INTERIOR/B-PILLAR LOWER TRIM -
INSTALLATION).
(6) Install the door sill trim (Refer to 23 - BODY/
INTERIOR/DOOR SILL TRIM - INSTALLATION).
(7) Install any other moldings or trim panels
removed.
INSTALLATION - CARGO AREA CARPET
(1) Thoroughly clean the area with Mopar Super
Kleent, or equivalent.
(2) Lay the new carpet in.
(3) Install the ªCº pillar trim (Refer to 23 - BODY/
INTERIOR/C-PILLAR TRIM - INSTALLATION).
(4) Install the CD changer, if equipped (Refer to 8 -
ELECTRICAL/AUDIO/CD CHANGER - INSTALLA-
TION).
(5) Install the footman loops (Fig. 3).
(6) Install the rear shoulder belts (Refer to 8 -
ELECTRICAL/RESTRAINTS/REAR SEAT BELT &
RETRACTOR - INSTALLATION).
(7) Install the rear seat backs (Refer to 23 -
BODY/SEATS/REAR SEAT BACK - INSTALLA-
TION).
(8) Install the Infinity amp, if equipped (Refer to 8
- ELECTRICAL/AUDIO/AMPLIFIER - INSTALLA-
TION).
(9) Install the spare tire cover.
(10) Install the retractable security cover.
COWL TRIM
REMOVAL
(1) Remove front door sill trim (Refer to 23 -
BODY/INTERIOR/DOOR SILL TRIM - REMOVAL).
(2) Remove screws attaching cowl trim to floor.
(3) Remove plastic nut.
(4) Grasp cowl trim and pull outward to separate
from clip.
(5) Separate cowl trim from vehicle.
INSTALLATION
(1) Position cowl trim and press into place.
(2) Install screws attaching cowl trim to floor.
(3) Install plastic nut.
(4) Install front door sill trim (Refer to 23 - BODY/
INTERIOR/DOOR SILL TRIM - INSTALLATION).
C-PILLAR TRIM
REMOVAL
(1) Remove rear shoulder belt turning loop.
(2) Remove rear shoulder belt height adjustment
knob.
(3) Remove screws attaching quarter panel trim.
(4) Pull quarter panel trim outward as necessary.
(5) Grasp C-pillar upper trim and pull outward to
disengage from C-pillar (Fig. 4).
(6) Route rear shoulder belt through access hole.
(7) Separate C-pillar upper trim from vehicle.
INSTALLATION
(1) Position C-pillar upper trim at C-pillar (Fig. 4).
(2) Route rear shoulder belt through access hole.
(3) Press C-pillar upper trim onto C-pillar.
(4) Press quarter panel trim into place as neces-
sary.
(5) Ensure front edge of trim is covered by weath-
erstrip.
(6) Install screws attaching quarter panel trim.
(7) Install rear shoulder belt height adjustment
knob.
(8) Install rear shoulder belt turning loop.
23 - 72 INTERIORWJ
CARPETS AND FLOOR MATS (Continued)