spark plug JEEP CHEROKEE 1995 Service User Guide

DIAGNOSTICS/SERVICE PROCEDURES
INDEX
page page
Automatic Shutdown (ASD) Relay Test.......... 6
Camshaft Position Sensor Test................ 6
Crankshaft Position Sensor Test............... 7
Distributor Cap............................ 7
Distributor Rotor........................... 8
DRB Scan Tool............................ 8
Engine Coolant Temperature Sensor Test........ 9
General Information........................ 6
Ignition Coil.............................. 9
Ignition Secondary Circuit Diagnosis........... 10Ignition Timing............................ 11
Intake Manifold Air Temperature Sensor Test..... 11
Manifold Absolute Pressure (MAP) Sensor Test . . . 11
On-Board Diagnostics...................... 15
Oxygen (O2S) Sensor Tests................. 15
Powertrain Control Module (PCM)............. 11
Spark Plug Secondary Cables................ 14
Spark Plugs............................. 12
Throttle Position Sensor Test................. 15
GENERAL INFORMATION
This section of the group, Diagnostics/Service Pro-
cedures, will discuss basic ignition system diagnostics
and service adjustments.
For system operation and component identification,
refer to the Component Identification/System Opera-
tion section of this group.
For removal or installation of ignition system com-
ponents, refer to the Component Removal/Installa-
tion section of this group.
For other useful information, refer to the On-Board
Diagnostics section.
For operation of the DRB Scan Tool, refer to the
appropriate Powertrain Diagnostic Procedures ser-
vice manual.
AUTOMATIC SHUTDOWN (ASD) RELAY TEST
To perform a complete test of this relay and its cir-
cuitry, refer to the DRB scan tool. Also refer to the
appropriate Powertrain Diagnostics Procedures man-
ual. To test the relay only, refer to RelaysÐOpera-
tion/Testing in the Group 14, Fuel Systems section.
CAMSHAFT POSITION SENSOR TEST
To perform a complete test of this sensor and its
circuitry, refer to the DRB scan tool. Also refer to the
appropriate Powertrain Diagnostics Procedures man-
ual. To test the sensor only, refer to the following:
The camshaft position sensor is located in the dis-
tributor (Fig. 1).
To perform a complete test of this sensor and its
circuitry, refer to the DRB scan tool. Also refer to the
appropriate Powertrain Diagnostics Procedures man-
ual. To test the sensor only, refer to the following:
For this test, an analog (non-digital) voltme-
ter is needed.Do not remove the distributor connec-
tor from the distributor. Using small paper clips,
insert them into the backside of the distributor wire
harness connector to make contact with the termi-nals. Be sure that the connector is not damaged
when inserting the paper clips. Attach voltmeter
leads to these paper clips.
(1) Connect the positive (+) voltmeter lead into the
sensor output wire. This is at done the distributor
wire harness connector. For wire identification, refer
to Group 8W, Wiring Diagrams.
(2) Connect the negative (-) voltmeter lead into the
ground wire. For wire identification, refer to Group
8W, Wiring Diagrams.
(3) Set the voltmeter to the 15 Volt DC scale.
(4) Remove distributor cap from distributor (two
screws). Rotate (crank) the engine until the distribu-
tor rotor is pointed to approximately the 11 o'clock
position. The movable pulse ring should now be
within the sensor pickup.
(5) Turn ignition key to ON position. The voltmeter
should read approximately 5.0 volts.
(6) If voltage is not present, check the voltmeter
leads for a good connection.
(7) If voltage is still not present, check for voltage
at the supply wire. For wire identification, refer to
Group 8W, Wiring Diagrams.
Fig. 1 Camshaft Position SensorÐTypical
8D - 6 IGNITION SYSTEMSJ

(8) If voltage is not present at supply wire, check
for voltage at pin-7 of powertrain control module
(PCM) 60-way connector. Leave the PCM connector
connected for this test.
(9) If voltage is still not present, perform vehicle
test using the DRB scan tool.
(10) If voltage is present at pin-7, but not at the
supply wire:
(a) Check continuity between the supply wire.
This is checked between the distributor connector
and pin-7 at the PCM. If continuity is not present,
repair the harness as necessary.
(b) Check for continuity between the camshaft
position sensor output wire and pin-44 at the PCM.
If continuity is not present, repair the harness as
necessary.
(c) Check for continuity between the ground cir-
cuit wire at the distributor connector and ground.
If continuity is not present, repair the harness as
necessary.
(11) While observing the voltmeter, crank the en-
gine with ignition switch. The voltmeter needle
should fluctuate between 0 and 5 volts while the en-
gine is cranking. This verifies that the camshaft po-
sition sensor in the distributor is operating properly
and a sync pulse signal is being generated.
If sync pulse signal is not present, replacement of
the camshaft position sensor is necessary.
For removal or installation of ignition system com-
ponents, refer to the Component Removal/Installa-
tion section of this group.
For system operation and component identification,
refer to the Component Identification/System Opera-
tion section of this group.
CRANKSHAFT POSITION SENSOR TEST
To perform a complete test of this sensor and its
circuitry, refer to the DRB scan tool. Also refer to the
appropriate Powertrain Diagnostics Procedures man-
ual. To test the sensor only, refer to the following:
The sensor is located on the transmission bellhous-
ing at the left/rear side of the engine block (Figs. 2, 3
or 4).
(1) Near the rear of the intake manifold, discon-
nect sensor pigtail harness connector from main wir-
ing harness.
(2) Place an ohmmeter across terminals B and C
(Fig. 5). Ohmmeter should be set to 1K-to-10K scale
for this test. The meter reading should be open (no
resistance). Replace sensor if a low resistance is indi-
cated.
For removal or installation of ignition system com-
ponents, refer to the Component Removal/Installa-
tion section of this group.DISTRIBUTOR CAP
INSPECTION
Remove the distributor cap and wipe it clean with
a dry lint free cloth. Visually inspect the cap for
cracks, carbon paths, broken towers, or damaged ro-
tor button (Figs. 6 and 7). Also check for white depos-
its on the inside (caused by condensation entering
the cap through cracks). Replace any cap that dis-
plays charred or eroded terminals. The inside flat
surface of a terminal end (faces toward rotor) will in-
dicate some evidence of erosion from normal opera-
tion. Examine the terminal ends for evidence of
mechanical interference with the rotor tip.
If replacement of the distributor cap is necessary,
transfer spark plug cables from the original cap to
the new cap. This should be done one cable at a time.
Each cable is installed onto the tower of the new cap
that corresponds to its tower position on the original
Fig. 2 Crankshaft Position SensorÐ2.5L 4-Cyl.
EngineÐTypical
Fig. 3 Crankshaft Position SensorÐ4.0L 6-Cyl.
EngineÐAll Except YJ models With Auto. Trans.
JIGNITION SYSTEMS 8D - 7

IGNITION COIL
To perform a complete test of the ignition coil and
its circuitry, refer to the DRB scan tool. Also refer tothe appropriate Powertrain Diagnostics Procedures
manual. To test the coil only, refer to the following:
The ignition coil (Fig. 11) is designed to operate
without an external ballast resistor.
Inspect the ignition coil for arcing. Test the coil ac-
cording to coil tester manufacturer's instructions.
Test the coil primary and secondary resistance. Re-
place any coil that does not meet specifications. Refer
to the Ignition Coil Resistance chart.
If the ignition coil is being replaced, the secondary
spark plug cable must also be checked. Replace cable
if it has been burned or damaged.
Arcing at the tower will carbonize the cable nipple,
which if it is connected to a new ignition coil, will
cause the coil to fail.
If the secondary coil cable shows any signs of dam-
age, it should be replaced with a new cable and new
terminal. Carbon tracking on the old cable can cause
arcing and the failure of a new ignition coil.
ENGINE COOLANT TEMPERATURE SENSOR TEST
For an operational description, diagnosis and re-
moval/installation procedures, refer to Group 14,
Fuel System.
IGNITION COIL RESISTANCE
Fig. 9 Firing OrderÐ4.0L 6-Cylinder Engine
Fig. 10 Rotor InspectionÐTypical
Fig. 11 Ignition CoilÐTypical (4.0L Shown)
JIGNITION SYSTEMS 8D - 9

IGNITION SECONDARY CIRCUIT DIAGNOSIS
CHECKING FOR SPARK
CAUTION: When disconnecting a high voltage cable
from a spark plug or from the distributor cap, twist
the rubber boot slightly (1/2 turn) to break it loose
(Fig. 12). Grasp the boot (not the cable) and pull it
off with a steady, even force.
(1) Disconnect the ignition coil secondary cable
from center tower of the distributor cap. Hold the ca-
ble terminal approximately 12 mm (1/2 in.) from a
good engine ground (Fig. 13).
WARNING: BE VERY CAREFUL WHEN THE ENGINE
IS CRANKING. DO NOT PUT YOUR HANDS NEAR
THE PULLEYS, BELTS OR THE FAN. DO NOT WEAR
LOOSE FITTING CLOTHING.
(2) Rotate (crank) the engine with the starter mo-
tor and observe the cable terminal for a steady arc. If
steady arcing does not occur, inspect the secondary
coil cable. Refer to Spark Plug Cables in this group.
Also inspect the distributor cap and rotor for cracksor burn marks. Repair as necessary. If steady arcing
occurs, connect ignition coil cable to the distributor
cap.
(3) Remove a cable from one spark plug.
(4) Using insulated pliers, hold the cable terminal
approximately 12 mm (1/2 in.) from the engine cylin-
der head or block while rotating the engine with the
starter motor. Observe the spark plug cable terminal
for an arc. If steady arcing occurs, it can be expected
that the ignition secondary system is operating cor-
rectly.(note that if the ignition coil cable is re-
moved for this test, instead of a spark plug
cable, the spark intensity will be much higher.)
If steady arcing occurs at the spark plug cables, but
the engine will not start, connect the DRB scan tool.
Refer to the Powertrain Diagnostic Procedures ser-
vice manual.
FAILURE TO START TEST
To prevent unnecessary diagnostic time and wrong
test results, the previous Checking For Spark test
should be performed prior to this test.
WARNING: SET PARKING BRAKE OR BLOCK THE
DRIVE WHEELS BEFORE PROCEEDING WITH THIS
TEST.
(1) Unplug the ignition coil harness connector at
the coil (Fig. 14).
(2) Connect a set of small jumper wires (18 gauge
or smaller) between the disconnected harness termi-
nals and the ignition coil terminals. To determine po-
larity at connector and coil, refer to the Wiring
Diagrams section.
(3) Attach one lead of a voltmeter to the positive
(12 volt) jumper wire. Attach the negative side of
voltmeter to a good ground. Determine that sufficient
battery voltage (12.4 volts) is present for the starting
and ignition systems.
Fig. 12 Cable Removal
Fig. 13 Checking for SparkÐTypical
Fig. 14 Coil Harness ConnectorÐTypical (4.0L
Shown)
8D - 10 IGNITION SYSTEMSJ

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. For identification, keep plugs ar-
ranged in the order in which they were removed from
the engine. An isolated plug displaying an abnormal
condition indicates that a problem exists in the cor-
responding cylinder. Replace spark plugs at the inter-
vals recommended in the maintenance chart in
Group 0, Lubrication 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. 19). 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 com-
bustion chamber. Spark plug performance is not af-
fected 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. 19). 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 cleaner element or repeated short operat-
ing times (short trips).
WET FOULING OR GAS FOULING
A spark plug coated with excessive wet fuel or oil is
wet fouled. In older engines, worn piston rings, leak-
ing valve guide seals or excessive cylinder wear can
cause wet fouling. In new or recently overhauled en-
gines, wet fouling may occur before break-in (normal
oil control) is achieved. This condition can usually be
resolved by cleaning and reinstalling the fouled
plugs.
OIL OR ASH ENCRUSTED
If one or more spark plugs are oil or oil ash en-
crusted (Fig. 20), evaluate engine condition for the
cause of oil entry into that particular combustion
chamber.
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
Fig. 18 PCM LocationÐXJ ModelsFig. 19 Normal Operation and Cold (Carbon) Fouling
8D - 12 IGNITION SYSTEMSJ

subjected to a high torque load, deposits partially liq-
uefy and bridge the gap between electrodes (Fig. 21).
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. 22). 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. Sparkplugs with scavenger deposits can be considered nor-
mal in condition and can be cleaned using standard
procedures.
CHIPPED ELECTRODE INSULATOR
A chipped electrode insulator usually results from
bending the center electrode while adjusting the
spark plug electrode gap. Under certain conditions,
severe detonation can also separate the insulator
from the center electrode (Fig. 23). Spark plugs with
this condition must be replaced.
PREIGNITION DAMAGE
Preignition damage is usually caused by excessive
combustion chamber temperature. The center elec-
trode dissolves first and the ground electrode dis-
solves somewhat latter (Fig. 24). Insulators appear
relatively deposit free. Determine if the spark plug
has the correct heat range rating for the engine. De-
termine if ignition timing is over advanced, or if
other operating conditions are causing engine over-
heating. (The heat range rating refers to the operat-
ing temperature of a particular type spark plug.
Spark plugs are designed to operate within specific
Fig. 20 Oil or Ash Encrusted
Fig. 21 Electrode Gap Bridging
Fig. 22 Scavenger Deposits
Fig. 23 Chipped Electrode Insulator
JIGNITION SYSTEMS 8D - 13

temperature ranges. This depends upon the thick-
ness and length of the center electrodes porcelain in-
sulator.)
SPARK PLUG OVERHEATING
Overheating is indicated by a white or gray center
electrode insulator that also appears blistered (Fig.
25). The increase in electrode gap will be consider-
ably in excess of 0.001 inch per 1000 miles of opera-
tion. This suggests that a plug with a cooler heat
range rating should be used. Over advanced ignition
timing, detonation and cooling system malfunctions
can also cause spark plug overheating.
SPARK PLUG SECONDARY CABLES
TESTING
Spark plug cables are sometimes referred to as sec-
ondary ignition cables or secondary wires. The cables
transfer electrical current from the distributor to in-
dividual spark plugs at each cylinder. The spark plug
cables are of nonmetallic construction and have a
built in resistance. The cables provide suppression of
radio frequency emissions from the ignition system.Check the high-tension cable connections for good
contact at the ignition coil, distributor cap towers
and spark plugs. Terminals should be fully seated.
The terminals and spark plug covers should be in
good condition. Terminals should fit tightly to the ig-
nition coil, distributor cap and spark plugs. The
spark plug cover (boot) of the cable should fit tight
around the spark plug insulator. Loose cable connec-
tions can cause corrosion and increase resistance, re-
sulting in shorter cable service life.
Clean the high tension cables with a cloth moist-
ened with a nonflammable solvent and wipe dry.
Check for brittle or cracked insulation.
When testing secondary cables for damage with an
oscilloscope, follow the instructions of the equipment
manufacturer.
If an oscilloscope is not available, spark plug cables
may be tested as follows:
CAUTION: Do not leave any one spark plug cable
disconnected for longer than necessary during test-
ing. This may cause possible heat damage to the
catalytic converter. Total test time must not exceed
ten minutes.
With the engine not running, connect one end of a
test probe to a good ground. Start the engine and run
the other end of the test probe along the entire
length of all spark plug cables. If cables are cracked
or punctured, there will be a noticeable spark jump
from the damaged area to the test probe. The cable
running from the ignition coil to the distributor cap
can be checked in the same manner. Cracked, dam-
aged or faulty cables should be replaced with resis-
tance type cable. This can be identified by the words
ELECTRONIC SUPPRESSION printed on the cable
jacket.
Use an ohmmeter to test for open circuits, exces-
sive resistance or loose terminals. Remove the dis-
tributor cap from the distributor.Do not remove
cables from cap.Remove cable from spark plug.
Connect ohmmeter to spark plug terminal end of ca-
ble and to corresponding electrode in distributor cap.
Resistance should be 250 to 1000 Ohms per inch of
cable. If not, remove cable from distributor cap tower
and connect ohmmeter to the terminal ends of cable.
If resistance is not within specifications as found in
the Spark Plug Cable Resistance chart, replace the
cable. Test all spark plug cables in this manner.
Fig. 24 Preignition Damage
Fig. 25 Spark Plug Overheating
SPARK PLUG CABLE RESISTANCE
8D - 14 IGNITION SYSTEMSJ

To test ignition coil-to-distributor cap cable, do not
remove the cable from the cap. Connect ohmmeter to
rotor button (center contact) of distributor cap and
terminal at ignition coil end of cable. If resistance is
not within specifications as found in the Spark Plug
Cable Resistance chart, remove the cable from the
distributor cap. Connect the ohmmeter to the termi-
nal ends of the cable. If resistance is not within spec-
ifications as found in the Spark Plug Cable
Resistance chart, replace the cable. Inspect the igni-
tion coil tower for cracks, burns or corrosion.
For removal and installation of spark plug cables,
refer to Spark Plug Secondary Cables in the Compo-
nent Removal/Installation section.
THROTTLE POSITION SENSOR TEST
For an operational description, diagnosis and re-
moval/installation procedures, refer to Group 14,
Fuel System.
OXYGEN (O2S) SENSOR TESTS
For an operational description, diagnosis or remov-
al/ installation procedures, refer to Group 14, Fuel
Systems.
ON-BOARD DIAGNOSTICS
FOR CERTAIN IGNITION SYSTEM
COMPONENTS
The powertrain control module (PCM) performs an
On-Board Diagnostic (OBD) check for certain ignition
system components on all vehicles. This is done by
setting a diagnostic trouble code (DTC).
A DTC can be obtained in two different ways. One
of the ways is by connecting the DRB scan tool to the
data link connector. This connector is located in the
engine compartment (Figs. 26 or 27). Refer to the ap-
propriate Powertrain Diagnostic Procedures service
manual for operation of the DRB scan tool. The other
way is to cycle the ignition key and observe the mal-
function indicator lamp (MIL). The MIL lamp is dis-
played on the instrument panel as the CHECK
ENGINE lamp (Figs. 28 or 29). This lamp will flash
a numeric code. If a numeric code number 11 (for the
crankshaft position sensor) or 42 (for the ASD relay)
is observed, a problem has been found in the ignition
system.
Note that the CHECK ENGINE lamp will illumi-
nate initially for approximately two seconds each
time the ignition key is turned to the ON position.
This is done for a bulb test.
Fig. 26 Data Link ConnectorÐXJ ModelsÐTypical
Fig. 27 Data Link ConnectorÐYJ ModelsÐTypical
JIGNITION SYSTEMS 8D - 15

COMPONENT REMOVAL/INSTALLATION
INDEX
page page
Automatic Shutdown (ASD) Relay............. 17
Camshaft Position Sensor................... 17
Crankshaft Position Sensor.................. 17
Distributor............................... 19
Engine Coolant Temperature Sensor........... 19
General Information....................... 17
Ignition Coil............................. 22Intake Manifold Air Temperature Sensor......... 23
Manifold Absolute Pressure (MAP) Sensor....... 23
Oxygen (O2S) Sensor...................... 23
Powertrain Control Module (PCM)............. 23
Spark Plug Secondary Cables................ 24
Spark Plugs............................. 23
Throttle Position Sensor (TPS)............... 25
GENERAL INFORMATION
This section of the group, Component Removal/In-
stallation, will discuss the removal and installation
of ignition system components.
For basic ignition system diagnostics and service
adjustments, refer to the Diagnostics/Service Proce-
dures section of this group.
For system operation and component identification,
refer to the Component Identification/System Opera-
tion section of this group.
AUTOMATIC SHUTDOWN (ASD) RELAY
The ASD relay is installed in the power distribu-
tion center (PDC) (Figs. 1 or 2). Relay location is
printed on the PDC cover.
REMOVAL
(1) Remove the PDC cover.
(2) Remove the relay by lifting straight up.
INSTALLATION
(1) Check the condition of relay wire terminals at
PDC before installing relay. Repair as necessary.
(2) Push the relay into the connector.
(3) Install the relay cover.
CAMSHAFT POSITION SENSOR
The camshaft position sensor is located in the dis-
tributor (Fig. 3).
REMOVAL
Distributor removal is not necessary to remove
camshaft position sensor.
(1) Disconnect negative battery cable at battery.
(2) Remove distributor cap from distributor (two
screws).
(3) Disconnect camshaft position sensor wiring
harness from main engine wiring harness.
(4) Remove distributor rotor from distributor shaft.
(5) Lift the camshaft position sensor assembly
from the distributor housing (Fig. 3).
INSTALLATION
(1) Install camshaft position sensor to distributor.
Align sensor into notch on distributor housing.
(2) Connect wiring harness.
(3) Install rotor.
(4) Install distributor cap. Tighten mounting
screws.
CRANKSHAFT POSITION SENSOR
The crankshaft position sensor is mounted in the
Fig. 1 PDCÐXJ Models
Fig. 2 PDCÐYJ Models
JIGNITION SYSTEMS 8D - 17

REMOVALÐ2.5L OR 4.0L 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. Do not re-
move rotor.
(4) Disconnect the distributor wiring harness from
the main engine harness.
(5) Remove the cylinder number 1 spark plug.
(6) Hold a finger over the open spark plug hole.
Rotate the engine at the vibration dampener bolt un-
til compression (pressure) is felt.
Slowly continue to rotate the engine. Do this until
the timing index mark on the vibration damper pul-
ley aligns with the top dead center (TDC) mark (0
degree) on timing degree scale (Fig. 9). Always rotate
the engine in direction of normal rotation. Do not ro-
tate the engine backward to align the timing marks.
On XJ models equipped with A/C, remove the elec-
trical cooling fan and shroud assembly from the radi-
ator. Refer to Group 7, Cooling System for
procedures.
This will provide room to turn the engine crank-
shaft with a socket and ratchet using the vibration
damper bolt.
(7) Remove the distributor holddown bolt and
clamp (Fig. 8).
(8) Remove the distributor from engine by slowly
lifting straight up.
Note that the rotor will rotate slightly in a counter-
clockwise direction while lifting up the distributor.
The oil pump gear will also rotate slightly in a coun-terclockwise direction while lifting up the distributor.
This is due to the helical cut gears on the distributor
and camshaft.
Note the removed position of the rotor during dis-
tributor removal. During installation, this will be re-
ferred to as the Pre-position.
2.5L 4-Cylinder Engine:Observe the slot in the
oil pump gear through the hole on the side of the en-
gine. It should be slightly before (counterclockwise of)
the 10 o'clock position (Fig. 10).
4.0L 6-Cylinder Engine:Observe the slot in the
oil pump gear through the hole on the side of the en-
gine. It should be slightly before (counterclockwise of)
the 11 o'clock position (Fig. 11).
(9) Remove and discard the old distributor-to-en-
gine block gasket (Fig. 8).
INSTALLATION
(1) If the engine crankshaft has been rotated after
distributor removal, cylinder number 1 must be re-
turned to its proper firing stroke. Refer to the previ-
ous REMOVAL steps number 5 and 6. These steps
must be done before installing distributor.
Fig. 9 Align Timing Marks
Fig. 10 Slot At 10 O'clock PositionÐ2.5L Engine
Fig. 11 Slot At 11 O'clock PositionÐ4.0L Engine
8D - 20 IGNITION SYSTEMSJ