SUNGLASS BIN AND SPRING ASSEMBLY
(1) Open sunglass bin door.
(2) Remove cover plate (Fig. 11).
(3) Unhook torque spring from wall and put in
down position as shown by arrow (Fig. 12).
(4) Remove sunglass bin door by flexing the center
panel and removing the side of the door with the
gear first (Fig. 13). The gear side of the door has a
short pivot rod. Slide door out of the compartment.
(5) Remove and discard push spring (Fig. 11).
(6) Install new push spring as shown. This may re-
quire flexing the housing in that area for clearance.
(7) Install new sunglass bin door in the open posi-
tion as follows:
(a) Make sure the torque spring lines up with
the slot in the longer pivot rod then insert the
longer pivot rod (Fig. 13).
(b) Flex the center panel and snap in the short
pivot rod.
(c) Hook torque spring back over the wall (Fig.
11).(d) Cycle door several times to ensure that the
door functions properly.
(8) Snap cover plate back in position as shown
(Fig. 11). Some pressure from the inside of the bins
may be required to engage all 6 snaps.
Fig. 11 Remove Cover Plate From Sunglass Bin
Fig. 12 Release Torque Spring
Fig. 13 Remove Sunglass Bin
8C - 8 OVERHEAD CONSOLEJ
For diagnostics, refer to the appropriate Powertrain
Diagnostic Procedures service manual for operation
of the DRB scan tool.
SPARK PLUGS
For spark plug removal, cleaning, gap adjustment
and installation, refer to the Component Removal/In-
stallation section of this group.
Faulty carbon and/or gas fouled plugs generally
cause hard starting, but they will clean up at higher
engine speeds. Faulty plugs can be identified in a
number of ways: poor fuel economy, power loss, de-
crease in engine speed, hard starting and, in general,
poor engine performance.
Remove the spark plugs and examine them for
burned electrodes and fouled, cracked or broken por-
celain insulators. Keep plugs arranged in the order
in which they were removed from the engine. An iso-
lated plug displaying an abnormal condition indi-
cates that a problem exists in the corresponding
cylinder. Replace spark plugs at the intervals recom-
mended in the maintenance chart in Group 0, Lubri-
cation and Maintenance.
Spark plugs that have low mileage may be cleaned
and reused if not otherwise defective. Refer to the
following Spark Plug Condition section of this group.
CONDITION
NORMAL OPERATING
The few deposits present on the spark plug will
probably be light tan or slightly gray in color. This is
evident with most grades of commercial gasoline
(Fig. 24). There will not be evidence of electrode
burning. Gap growth will not average more than ap-
proximately 0.025 mm (.001 in) per 1600 km (1000
miles) of operation. Spark plugs that have normal
wear can usually be cleaned, have the electrodes
filed, have the gap set and then be installed.Some fuel refiners in several areas of the United
States have introduced a manganese additive (MMT)
for unleaded fuel. During combustion, fuel with
MMT causes the entire tip of the spark plug to be
coated with a rust colored deposit. This rust color can
be misdiagnosed as being caused by coolant in the
combustion chamber. Spark plug performance is not
affected by MMT deposits.
COLD FOULING/CARBON FOULING
Cold fouling is sometimes referred to as carbon
fouling. The deposits that cause cold fouling are ba-
sically carbon (Fig. 24). A dry, black deposit on one
or two plugs in a set may be caused by sticking
valves or defective spark plug cables. Cold (carbon)
fouling of the entire set of spark plugs may be caused
by a clogged air filter or repeated short operating
times (short trips).
ELECTRODE GAP BRIDGING
Electrode gap bridging may be traced to loose de-
posits in the combustion chamber. These deposits ac-
cumulate on the spark plugs during continuous stop-
and-go driving. When the engine is suddenly
subjected to a high torque load, deposits partially liq-
uefy and bridge the gap between electrodes (Fig. 25).
This short circuits the electrodes. Spark plugs with
electrode gap bridging can be cleaned using standard
procedures.
SCAVENGER DEPOSITS
Fuel scavenger deposits may be either white or yel-
low (Fig. 26). They may appear to be harmful, but
this is a normal condition caused by chemical addi-
tives in certain fuels. These additives are designed to
change the chemical nature of deposits and decrease
spark plug misfire tendencies. Notice that accumula-
tion on the ground electrode and shell area may be
heavy, but the deposits are easily removed. Spark
Fig. 24 Normal Operation and Cold (Carbon) Fouling
Fig. 25 Electrode Gap Bridging
8D - 16 IGNITION SYSTEMSJ
REMOVALÐALL ENGINES
(1) Near the rear of the intake manifold, discon-
nect the pigtail harness (on the sensor) from the
main electrical harness.
(2) Remove the nut holding sensor wire clip to fuel
rail mounting stud.
(3) Depending upon application, remove either the
sensor mounting bolt(s) or nuts.
(4) Remove the sensor.
(5) Remove clip from sensor wire harness.
INSTALLATIONÐALL EXCEPT YJ MODELS
WITH 4.0L ENGINE AND AUTOMATIC
TRANSMISSION
(1) Install the sensor flush against the opening in
the transmission housing.
(2) Install and tighten the two sensor mounting
bolts (or nuts) to 19 Nzm (14 ft. lbs.) torque.
CAUTION: On some models, two bolts used to se-
cure the sensor to the transmission. These bolts
are specially machined to correctly space the unit
to the flywheel. Do not attempt to install any other
bolts.
(3) Connect the electrical connector to the sensor.
(4) Install clip on sensor wire harness.
(5) Install clip over fuel rail mounting stud. Install
clip mounting nut.
INSTALLATIONÐYJ MODELS WITH 4.0L
ENGINE AND AUTOMATIC TRANSMISSION
(1) Be sure the paper/cardboard spacer (Fig. 7) has
been installed to the bottom of the new sensor.If original sensor is being reinstalled (such as with
transmission or flywheel removal), clean bottom of
the sensor before installation. Obtain a new spacer
and remove the paper backing. Install the self-adhe-
sive side to bottom of sensor. This spacerMUSTbe
installed. If spacer is not installed, sensor will be
damaged when engine is started.
(2) Position sensor to transmission bellhousing and
install mounting bolt finger tight.
(3) Gently seat (push down) the sensor until the
paper spacer contacts the outer edge of the flywheel.
(4) Tighten sensor mounting bolt (Fig. 7) to 17-
to-21 Nzm (13-to-16 ft. lbs.) torque.
(5) Connect the electrical connector to sensor.
(6) Install the clip to sensor wire harness.
(7) Install clip over fuel rail mounting stud. Install
clip mounting nut.
ENGINE COOLANT TEMPERATURE SENSOR
WARNING: HOT, PRESSURIZED COOLANT CAN
CAUSE INJURY BY SCALDING. COOLING SYSTEM
MUST BE PARTIALLY DRAINED BEFORE REMOV-
ING THE COOLANT TEMPERATURE SENSOR. RE-
FER TO GROUP 7, COOLING.
REMOVAL
The sensor is installed in the thermostat housing
(Fig. 8).
(1) Drain cooling system until the coolant level is
below the cylinder head. For cooling system draining,
refer to Group 7, Cooling.
(2) Disconnect the coolant temperature sensor wire
connector.
(3) Remove the sensor from the thermostat hous-
ing (Fig. 8).
Fig. 7 Crankshaft Position SensorÐ4.0L EngineÐYJ
models With Automatic Transmission
Fig. 8 Coolant Temperature SensorÐTypical
8D - 22 IGNITION SYSTEMSJ
INSTALLATION
(1) Install coolant temperature sensor into the
thermostat housing. Tighten to 28 Nzm (21 ft. lbs.)
torque.
(2) Connect the wire connector.
(3) Fill the cooling system. Refer to group 7, Cool-
ing System.
DISTRIBUTOR
All distributors contain an internal oil seal that
prevents oil from entering the distributor housing.
The seal is not serviceable.
The camshaft position sensor is located in the dis-
tributor on all engines (Fig. 9).
Refer to Fig. 9 for an exploded view of the distrib-
utor.
REMOVALÐ2.5L ENGINE
(1) Disconnect the negative battery cable at the
battery.
(2) Disconnect coil secondary cable at coil.
(3) Remove distributor cap from distributor (2
screws). Do not remove cables from cap.
(4) Disconnect the distributor wiring harness from
the main engine harness.
(5) Scribe a mark on the distributor housing in
line with the tip of the rotor. Note the position of the
rotor and distributor housing. This is in relation tothe surrounding engine components as reference
points for installing the distributor.
(6) Remove the distributor holddown bolt and
clamp.
(7) Remove the distributor from engine by lifting
straight up. Remove and discard old distributor-to-
engine block gasket. Note that the rotor will rotate
slightly in a counterclockwise direction while lifting
up the distributor. Note this position after removal.
INSTALLATIONÐ2.5L ENGINE
ENGINE NOT ROTATED AFTER REMOVAL
This procedure assumes that the engine was not ro-
tated with distributor out of engine.
(1) Clean the distributor mounting hole area of the
engine block.
(2) Install a new distributor-to-engine block gas-
ket.
There is a fork on the distributor housing where
the housing seats against the engine block. The slot
in the fork aligns with the distributor holddown bolt
hole in the engine block. The distributor is correctly
installed when the rotor is correctly positioned. This
is with the slot in the fork aligned with the hold-
down bolt hole in the cylinder block. Because of the
fork on the distributor housing, initial ignition tim-
ing is not adjustable (the distributor cannot be rotat-
ed).
(3) Position the distributor shaft in the cylinder
block. If the engine was not rotated while the distrib-
utor was removed, perform the following:
²Align the rotor tip with the scribe mark on the
distributor housing during removal. Turn the rotor
approximately 1/8-turn counterclockwise past the
scribe mark.
CAUTION: Be sure that the distributor shaft fully
engages into the oil pump drive gear shaft. It may
be necessary to slightly rotate (bump) the engine.
This is done while applying downward hand force
on the distributor body. It should fully engage the
distributor shaft with the oil pump drive gear shaft.
²Slide the distributor shaft down into the engine.
It may be necessary to move the rotor and shaft
(slightly) to engage the distributor shaft with the slot
in the oil pump shaft. The same may have to be done
to engage the distributor gear with the camshaft
gear. However, the rotor should align with the scribe
mark when the distributor shaft is down in place.
²Install the distributor holddown clamp and bolt.
Tighten the bolt to 23 Nzm (17 ft. lbs.) torque.
(4) Install the distributor cap (with the ignition ca-
bles) on the distributor housing (Fig. 10). Tighten
distributor cap holddown screws to 3 Nzm (26 in. lbs.)
torque.
(5) Connect the distributor wiring harness to the
main engine harness.
Fig. 9 DistributorÐ2.5L/4.0L EnginesÐTypical
JIGNITION SYSTEMS 8D - 23
CAUTION: Do not puncture the spark plug cables or
boots to make the connection. Use proper adapters.
(6) Connect battery cable to battery.
ENGINE ROTATED AFTER REMOVAL
There is a fork on the distributor housing where
the housing seats against the engine block. The slot
in the fork aligns with the hole for the distributor
holddown bolt in the engine block. The distributor is
correctly installed when the rotor is correctly posi-
tioned. This is when the slot in the fork is aligned
with the hole for the distributor holddown bolt in the
cylinder block. Because of the fork on the distributor
housing, initial ignition timing is not adjustable (the
distributor cannot be rotated).
(1) If the engine was rotated while the distributor
was removed, it will be necessary to establish timing
according to following procedure:
²Remove the No. 1 spark plug. Hold a finger over
the spark plug hole and rotate the engine until com-
pression pressure is felt. Slowly continue to rotate
the engine. Do this until the timing index on vibra-
tion damper pulley aligns with top dead center (TDC)mark (0 degree) on timing degree scale. Always ro-
tate the engine in direction of normal rotation. Do
not turn the engine backward to align the timing
marks.
²Using a flat blade screwdriver, rotate the oil pump
gear. Do this to position the gear slot on the oil
pump shaft slightly before the 11 o'clock position
(Fig. 11).
²With the distributor cap removed, install the dis-
tributor with the rotor located just past the 2 o'clock
position (Fig. 12).
²When distributor is fully engaged in its correct lo-
cation, the rotor should be just past the 3 o'clock po-
sition (Fig. 13).
²Install the distributor holddown clamp and bolt.
Tighten the holddown bolt to 23 Nzm (17 ft. lbs.)
torque.
CAUTION: If the distributor cap is incorrectly posi-
tioned on distributor housing, the cap or rotor may
be damaged when engine is started.
(2) Install the distributor cap (with ignition cables)
on the distributor housing. Be sure that the cap fits
securely on rim of the distributor housing.
(3) Connect the distributor wiring harness to the
main engine harness.
CAUTION: Do not puncture the spark plug cables or
boots to make the connection. Use proper adapters.
REMOVALÐ4.0L ENGINE
The distributor used in the 4.0L engine contains an
internal oil seal that prevents oil from entering the
distributor housing. The seal is not serviceable.
Fig. 11 Align Oil Pump Gear SlotÐ2.5L Engine
Fig. 10 Spark Plug Cable PositionsÐ2.5L Engine
Fig. 12 Distributor InstallationÐ2.5L Engine
8D - 24 IGNITION SYSTEMSJ
The oil pump shaft is located down in the distribu-
tor hole.
(4) Install the rotor.
(5) Without engaging the distributor gear into the
cam gear, position the distributor into the hole in the
engine block. Be sure the distributor gasket is in-
stalled.
(6) Visually line up the holddown ear of the dis-
tributor housing with the holddown clamp hole (Fig.
18).
(7) Turn the rotor to the 4 o'clock position (Fig.
19).
(8) Slide the distributor down into the block until
it seats. Keep the holddown ear aligned to the hole
in the block.
(9) The rotor should be in the 5 o'clock position.
This is with the trailing edge of rotor blade lined up
with scribe mark on distributor housing (number one
spark plug cable post location).(10) Install the distributor holddown clamp bolt
and tighten to 23 Nzm (17 ft. lbs.) torque.
(11) Install the distributor cap and connect the dis-
tributor electrical connector.
(12) Install electrical cooling fan and shroud if ap-
plicable.
(13) Connect battery cable to battery.
IGNITION COIL
The ignition coil is an epoxy filled type. If the coil
is replaced, it must be replaced with the same type.
Fig. 16 Align Rotor Trailing Edge With Scribe Mark
Fig. 17 Align Oil Pump Gear ShaftÐ4.0L Engine
Fig. 18 Distributor InstallationÐTypical
Fig. 19 Rotor Alignment
8D - 26 IGNITION SYSTEMSJ
REMOVAL
The ignition coil is mounted to the right side of the
engine block next to the distributor (Fig. 20).
(1) Disconnect the ignition coil secondary cable
from ignition coil (Fig. 20).
(2) Disconnect engine harness connector from igni-
tion coil.
(3) Remove ignition coil mounting bolts. Remove
coil.
INSTALLATION
(1) Install ignition coil to bracket on cylinder block
with mounting bolts.
(2) Connect engine harness connector to coil.
(3) Connect ignition coil cable to ignition coil.
INTAKE MANIFOLD AIR TEMPERATURE SENSOR
REMOVAL
The intake manifold air temperature sensor is in-
stalled into the intake manifold plenum (Figs. 21 or
22).(1) Disconnect the electrical connector from the
sensor.
(2) Remove the sensor from the intake manifold.
INSTALLATION
(1) Install the air temperature sensor into the in-
take manifold. Tighten the sensor to 13 Nzm (10 ft.
lbs.) torque.
(2) Connect the electrical connector to the sensor.
MANIFOLD ABSOLUTE PRESSURE (MAP) SENSOR
The MAP sensor is located on the dash panel near
the rear of the engine cylinder head (valve) cover
(Fig. 23).
REMOVAL
(1) Disconnect the MAP sensor electrical connector
(Fig. 23).
(2) Disconnect the MAP sensor vacuum supply
hose (Fig. 23).
(3) Remove the MAP sensor mounting nuts and re-
move MAP sensor.
Fig. 20 Ignition CoilÐTypical
Fig. 21 Air Temperature SensorÐ2.5L Engine
Fig. 22 Air Temperature SensorÐ4.0L Engine
Fig. 23 MAP SensorÐTypical
JIGNITION SYSTEMS 8D - 27
INSTALLATION
(1) Install MAP sensor to dash panel and secure
with mounting nuts.
(2) Install the MAP sensor vacuum supply hose.
(3) Connect the MAP sensor electrical connector.
OXYGEN (O2S) SENSOR
For diagnostics and removal/installation proce-
dures, refer to Group 14, Fuel Systems, in this man-
ual.
POWERTRAIN CONTROL MODULE (PCM)
The PCM was formerly referred to as the SBEC or
engine controller.
XJ MODELS
On XJ models, the PCM is located in the engine
compartment next to the air cleaner (Fig. 24).
REMOVAL
(1) Disconnect negative battery cable at battery.
(2) Loosen 60-way connector mounting screw until
connector can be disengaged from PCM.
(3) Pull 60-way connector straight back from PCM.
(4) Remove PCM mounting bolts.
(5) Remove PCM from vehicle.
INSTALLATION
(1) Check the pins in the PCM 60-way electrical
connector for damage. Repair as necessary.
(2) Install PCM. Tighten mounting bolts to 1 Nzm
(9 in. lbs.) torque.
(3) Engage 60-way connector into PCM. Tighten
connector mounting screw to 4 Nzm (35 in. lbs.)
torque.
(4) Connect battery cable to battery.
YJ MODELS
On YJ models, the PCM is located in the engine
compartment behind the windshield washer fluid res-
ervoir (Fig. 25).REMOVAL
(1) Disconnect negative battery cable at battery.
(2) Remove windshield washer fluid reservoir.
(3) Loosen 60-way connector mounting screw until
connector can be disengaged from PCM.
(4) Pull 60-way connector straight back from PCM.
(5) Remove PCM mounting bolts.
(6) Remove PCM from vehicle.
INSTALLATION
(1) Check the pins in the PCM 60-way electrical
connector for damage. Repair as necessary.
(2) Install PCM. Tighten mounting bolts to 1 Nzm
(9 in. lbs.) torque.
(3) Engage 60-way connector into PCM. Tighten con-
nector mounting screw to 4 Nzm (35 in. lbs.) torque.
(4) Connect battery cable to battery.
(5) Install washer fluid reservoir.
SPARK PLUGS
PLUG REMOVAL
(1) Always remove spark plug or ignition coil ca-
bles by grasping at the cable boot. Turn the cable
boot 1/2 turn and pull straight back in a steady mo-
tion. Never pull directly on the cable. Internal dam-
age to cable will result.
(2) Prior to removing the spark plug, spray com-
pressed air around the spark plug hole and the area
around the spark plug. This will help prevent foreign
material from entering the combustion chamber.
(3) Remove the spark plug using a quality socket
with a rubber or foam insert.
(4) Inspect the spark plug condition. Refer to
Spark Plugs in the Diagnostics/Service Procedures
section of this group.
PLUG CLEANING
The plugs may be cleaned using commercially
available spark plug cleaning equipment. After
Fig. 24 PCM LocationÐXJ Models
Fig. 25 PCM LocationÐYJ Models
8D - 28 IGNITION SYSTEMSJ