DIAGRAM INDEX
Component Page
Chime/Buzzer Module......................8W-50-6
Dimming Module.........................8W-50-9
Dimming Relay..........................8W-50-8
Fog Lamp Relay........................8W-50-10
Fog Lamp Switch........................8W-50-10
Fuse 5 (Fuse Block).......................8W-50-7
Fuse 5 (PDC).........................8W-50-4, 8
Fuse 6 (PDC).........................8W-50-6, 8
Fuse 7 (PDC)..........................8W-50-10
Fuse 9 (Fuse Block).......................8W-50-4
Fuse 10 (Fuse Block)......................8W-50-7
Fuse 11 (Fuse Block)......................8W-50-8
Fuse 13 (PDC).........................8W-50-10
Fuse 20 (Fuse Block)......................8W-50-8
Fuse 26 (Fuse Block)......................8W-50-6
Headlamp Delay Module....................8W-50-7
Headlamp Dimmer Switch.................8W-50-4, 7
Headlamp Switch.....................8W-50-4, 7, 9
Headlamp Relay.........................8W-50-9
Ignition Switch........................8W-50-6, 8
Instrument Cluster........................8W-50-5
Left Fog Lamp.........................8W-50-10
Left Headlamp..........................8W-50-5
Left Marker Lamp........................8W-50-5
Left Tail, Stop and Turn Signal Lamp............8W-50-5
Overhead Console......................8W-50-4, 8
Right Fog Lamp........................8W-50-10
Right Headlamp.........................8W-50-5
Right Tail, Stop and Turn Signal Lamp...........8W-50-5
Telltale Connector (Instrument Cluster)...........8W-50-9
J8W-50 FRONT LIGHTINGÐXJ-RHD 8W - 50 - 3
REAR LIGHTING
TAIL LAMPS AND REAR LICENSE PLATE LAMPS
Circuit A3 from fuse 5 in the Power Distribution
Center (PDC) connects to a bus bar in the fuse block
which feeds circuit L7. Fuse 9 in the fuse block pro-
tects circuit L7.
The headlamp switch has three positions: ON,
PARK (parking lamps) and OFF, plus a dimmer
switch. When the headlamp switch is in the PARK or
ON position, the switch connects circuit L7 to circuit
L90. From the headlamp switch, circuit L90 branches
to power the front parking lamps and rear tail
lamps, side marker lamps, and rear license plate
lamps.
GROUND CIRCUIT
Circuit Z1 provides a ground for the parking lamps,
tail lamps, and rear license plate lamps.
HELPFUL INFORMATION
²Check fuse 5 in PDC.
²Check fuse 9 in the fuse block.
²When the headlamp switch is in the PARK or ON
position, circuit L7 also connects to circuit E2. Cir-
cuit E2 continues through fuse 25 in the fuse block.
Circuit E2 powers the illumination lamps.
STOP LAMPS AND CHMSL LAMPS
Circuit L9 from fuse 4 in the Power Distribution
Center (PDC) connects to the stop lamp switch.
When the operator depresses the brake pedal, the
stop lamp switch closes and connects circuit L9 to
circuit L50. Circuit L50 connects to the stop lamps
and center high mounted stop lamps (CHMSL). Cir-
cuit Z1 provides a ground for the stop lamps.
HELPFUL INFORMATION
²Check fuses 13 in the PDC.
²Check for continuity across the stop lamp switch
when it is closed.
BACK-UP LAMPS
In the START or RUN position, the ignition switch
connects circuit A1 from fuse 6 in the Power Distri-
bution Center (PDC) to circuit A21. Circuit A21 feeds
a bus bar in the PDC that powers circuit F12
through fuse 11.
Circuit F12 supplies power to the back-up lamp
switch. On automatic transmission equipped vehicles,
the back-up lamp switch is part of an assembly that
includes the PARK/NEUTRAL position switch. When
the operator puts the transmission in REVERSE, the
back-up lamp switch connects circuit F12 to circuit
L10. Circuit L10 feeds the back-up lamps. Circuit Z1
provides ground for the back-up lamps.
HELPFUL INFORMATION
²Check fuses 6 and 11 in the PDC.
²Check for continuity across the back-up lamp
switch when it is closed.
DIAGRAM INDEX
Component Page
Center High Mounted Stop Lamps (CHMSL).......8W-51-3
Fuse 4 (PDC)...........................8W-51-3
Fuse 5 (PDC)...........................8W-51-2
Fuse 6 (Fuse Block).......................8W-51-2
Fuse 6 (PDC)...........................8W-51-2
Fuse 9 (Fuse Block).......................8W-51-2
Headlamp Switch.........................8W-51-2
Ignition Switch..........................8W-51-2
Left Back-Up Lamp.......................8W-51-4
Left Side Marker Lamp.....................8W-51-4
Left Tail/Stop Lamp.......................8W-51-4
Left Turn Signal Lamp.....................8W-51-4
License Plate Lamp.......................8W-51-3
Park/Neutral Position Switch.................8W-51-2
Right Back-Up Lamp......................8W-51-5
Right Side Marker Lamp....................8W-51-5
Right Tail/Stop Lamp......................8W-51-4
Right Turn Signal Lamp....................8W-51-5
Stop Lamp Switch........................8W-51-3
J8W-51 REAR LIGHTINGÐXJ-RHD 8W - 51 - 1
Fig. 1 Front End Lighting Connectors
J8W-90 CONNECTOR LOCATIONSÐXJ-RHD 8W - 90 - 3
Fig. 1 Front End Lighting Splices XJ-RHD
Fig. 2 Engine Compartment Splices, Left Side XJ-RHD
J8W-95 SPLICE LOCATIONSÐXJ-RHD 8W - 95 - 3
ENGINES
CONTENTS
page page
LUBRICATION SYSTEM................... 37
LUBRICATION SYSTEM................... 79
2.5L ENGINE SERVICE PROCEDURES....... 134.0L ENGINE SERVICE PROCEDURES....... 55
ENGINE DIAGNOSIS...................... 5
STANDARD SERVICE PROCEDURES......... 1
STANDARD SERVICE PROCEDURES
INDEX
page page
Engine Performance........................ 2
Form-In-Place Gaskets...................... 1
Honing Cylinder Bores...................... 2
Hydrostatic Lock........................... 4Measuring with Plastigage.................... 3
Repair Damaged or Worn Threads............. 4
Service Engine Assembly (Short Block).......... 4
FORM-IN-PLACE GASKETS
There are several places where form-in-place gas-
kets are used on the engine.DO NOT use form-in-
place gasket material unless specified.Care
must be taken when applying form-in-place gaskets.
Bead size, continuity and location are of great impor-
tance. Too thin a bead can result in leakage while too
much can result in spill-over. A continuous bead of
the proper width is essential to obtain a leak-free
joint.
Two types of form-in-place gasket materials are
used in the engine area (Mopar Silicone Rubber Ad-
hesive Sealant and Mopar Gasket Maker). Each have
different properties and cannot be used interchange-
ably.
MOPAR SILICONE RUBBER ADHESIVE
SEALANT
Mopar Silicone Rubber Adhesive Sealant, normally
black in color, is available in 3 ounce tubes. Moisture
in the air causes the sealant material to cure. This
material is normally used on flexible metal flanges.
It has a shelf life of a year and will not properly cure
if over aged. Always inspect the package for the ex-
piration date before use.
MOPAR GASKET MAKER
Mopar Gasket Maker, normally red in color, is
available in 6 cc tubes. This anaerobic type gasket
material cures in the absence of air when squeezedbetween smooth machined metallic surfaces. It will
not cure if left in the uncovered tube. DO NOT use
on flexible metal flanges.
SURFACE PREPARATION
Parts assembled with form-in-place gaskets may be
disassembled without unusual effort. In some in-
stances, it may be necessary to lightly tap the part
with a mallet or other suitable tool to break the seal
between the mating surfaces. A flat gasket scraper
may also be lightly tapped into the joint but care
must be taken not to damage the mating surfaces.
Scrape or wire brush all gasket surfaces to remove
all loose material. Inspect stamped parts to ensure
gasket rails are flat. Flatten rails with a hammer on
a flat plate, if required. Gasket surfaces must be free
of oil and dirt. Make sure the old gasket material is
removed from blind attaching holes.
GASKET APPLICATION
Assembling parts using a form-in-place gasket re-
quires care.
Mopar Silicone Rubber Adhesive Sealant should be
applied in a continuous bead approximately 3 mm
(0.12 inch) in diameter. All mounting holes must be
circled. For corner sealing,a3or6mm(1/8 or 1/4
inch) drop is placed in the center of the gasket con-
tact area. Uncured sealant may be removed with a
shop towel. Components should be torqued in place
while the sealant is still wet to the touch (within 10
JENGINES 9 - 1
minutes). The use of a locating dowel is recom-
mended during assembly to prevent smearing the
material off location.
Mopar Gasket Maker should be applied sparingly
to one gasket surface. The sealant diameter should
be 1.00 mm (0.04 inch) or less. Be certain the mate-
rial surrounds each mounting hole. Excess material
can easily be wiped off. Components should be
torqued in place within 15 minutes. The use of a lo-
cating dowel is recommended during assembly to pre-
vent smearing the material off location.
ENGINE PERFORMANCE
To provide best vehicle performance and lowest ve-
hicle emissions, it is most important that the tune-up
be done accurately. Use the specifications listed on
the Vehicle Emission Control Information label found
on the engine compartment hood.
(1) Test battery specific gravity. Add water, if nec-
essary. Clean and tighten battery connections.
(2) Test cranking amperage draw (refer to Group
8B, Battery/Starter Service for the proper proce-
dures).
(3) Tighten the intake manifold bolts (refer to
Group 11, Exhaust System and Intake Manifold for
the proper specifications).
(4) Perform cylinder compression test:
(a) Check engine oil level and add oil, if neces-
sary.
(b) Drive the vehicle until engine reaches normal
operating temperature.
(c) Select a route free from traffic and other
forms of congestion, observe all traffic laws and
briskly accelerate through the gears several times.
The higher engine speed may help clean out valve
seat deposits which can prevent accurate compres-
sion readings.
CAUTION: DO NOT overspeed the engine.
(d) Remove all spark plugs from engine. As spark
plugs are being removed, check electrodes for ab-
normal firing indicatorsÐfouled, hot, oily, etc.
Record cylinder number of spark plug for future
reference.
(e) Disconnect coil wire from distributor and se-
cure to good ground to prevent a spark from start-
ing a fire.
(f) Be sure throttle blades are fully open during
the compression check.
(g) Insert compression gage adaptor into the
No.1 spark plug hole. Crank engine until maximum
pressure is reached on gauge. Record this pressure
as No.1 cylinder pressure.
(h) Repeat Step 4g for all remaining cylinders.
(i) Compression should not be less than 689 kPa
(100 psi) and not vary more than 172 kPa (25 psi)
from cylinder to cylinder.(j) If cylinder(s) have abnormally low compres-
sion pressures, repeat steps 4a through 4h.
(k) If the same cylinder(s) repeat an abnormally
low reading, it could indicate the existence of a
problem in the cylinder.
The recommended compression pressures are
to be used only as a guide to diagnosing engine
problems. An engine should NOT be disassem-
bled to determine the cause of low compression
unless some malfunction is present.
(5) Clean or replace spark plugs as necessary. Ad-
just gap (refer to Group 8D, Ignition System for gap
adjustment and torque).
(6) Test resistance of spark plug cables (refer to
Group 8D, Ignition System).
(7) Inspect the primary wire. Test coil output volt-
age, primary and secondary resistance. Replace parts
as necessary (refer to Group 8D, Ignition System and
make necessary adjustment).
(8) Perform a combustion analysis.
(9) Test fuel pump for pressure (refer to Group 14,
Fuel System for the proper specifications).
(10) Inspect air filter element (refer to Group 0,
Lubrication and Maintenance for the proper proce-
dure).
(11) Inspect crankcase ventilation system (refer to
Group 0, Lubrication and Maintenance for the proper
procedure).
(12) For emission controls refer to Group 25, Emis-
sion Controls System for service procedures.
(13) Inspect and adjust accessory belt drives (refer
to Group 7, Cooling System for the proper adjust-
ments).
(14) Road test vehicle as a final test.
HONING CYLINDER BORES
Before honing, stuff plenty of clean shop towels un-
der the bores and over the crankshaft to keep abra-
sive materials from entering the crankshaft area.
(1) Used carefully, the Cylinder Bore Sizing Hone
C-823 equipped with 220 grit stones, is the best tool
for this job. In addition to deglazing, it will reduce
taper and out-of-round as well as removing light
scuffing, scoring or scratches. Usually a few strokes
will clean up a bore and maintain the required lim-
its.
CAUTION: DO NOT use rigid type hones to remove
cylinder wall glaze.
(2) Deglazing of the cylinder walls may be done if
the cylinder bore is straight and round. Use a cylin-
der surfacing hone, Honing Tool C-3501, equipped
with 280 grit stones (C-3501-3810). 20-60 strokes, de-
pending on the bore condition, will be sufficient to
provide a satisfactory surface. Using honing oil
C-3501-3880 or a light honing oil available from ma-
jor oil distributors.
9 - 2 ENGINESJ
CYLINDER COMBUSTION PRESSURE LEAKAGE
TEST
The combustion pressure leakage test provides an
accurate means for determining engine condition.
Combustion pressure leakage testing will detect:
²Exhaust and intake valve leaks (improper seat-
ing).
²Leaks between adjacent cylinders or into water
jacket.
²Any causes for combustion/compression pressure
loss.
WARNING: DO NOT REMOVE THE RADIATOR CAP
WITH THE SYSTEM HOT AND UNDER PRESSURE
BECAUSE SERIOUS BURNS FROM COOLANT CAN
OCCUR.
Check the coolant level and fill as required. DO
NOT install the radiator cap.
Start and operate the engine until it attains nor-
mal operating temperature, then turn the engine
OFF.
Remove the spark plugs.
Remove the oil filler cap.
Remove the air cleaner.
Calibrate the tester according to the manufactur-
er's instructions. The shop air source for testing
should maintain 483 kPa (70 psi) minimum, 1 379
kPa (200 psi) maximum and 552 kPa (80 psi) recom-
mended.
Perform the test procedures on each cylinder ac-
cording to the tester manufacturer's instructions.
While testing, listen for pressurized air escaping
through the throttle body, tailpipe and oil filler cap
opening. Check for bubbles in the radiator coolant.
All gauge pressure indications should be equal,
with no more than 25% leakage.
FOR EXAMPLE:At 552 kPa (80 psi) input pres-
sure, a minimum of 414 kPa (60 psi) should be main-
tained in the cylinder.
Refer to the Cylinder Combustion Pressure Leak-
age Test Diagnosis chart.
INSPECTION (ENGINE OIL LEAKS IN GENERAL)
Begin with a through visual inspection of the en-
gine, particularly at the area of the suspected leak. If
an oil leak source is not readily identifiable, the fol-
lowing steps should be followed:
(1) Do not clean or degrease the engine at this
time because some solvents may cause rubber to
swell, temporarily stopping the leak.
(2) Add an oil soluble dye (use as recommended by
manufacturer). Start the engine and let idle for ap-
proximately 15 minutes. Check the oil dipstick to
make sure the dye is thoroughly mixed as indicated
with a bright yellow color under a black light.(3) Using a black light, inspect the entire engine
for fluorescent dye, particularly at the suspected area
of oil leak. If the oil leak is found and identified, re-
pair per service manual instructions.
(4) If dye is not observed, drive the vehicle at var-
ious speeds for approximately 24km (15 miles), and
repeat step (3).
If the oil leak source is not positively identi-
fied at this time, proceed with the air leak detec-
tion test method as follows:
(1) Disconnect the breather cap to air cleaner hose
at the breather cap end. Cap or plug breather cap
nipple.
(2) Remove the PCV valve from the cylinder head
cover. Cap or plug the PCV valve grommet.
(3) Attach an air hose with pressure gauge and
regulator to the dipstick tube.
CAUTION: Do not subject the engine assembly to
more than 20.6 kpa (3 PSI) of test pressure.
(4) Gradually apply air pressure from 1 psi to 2.5
psi maximum while applying soapy water at the sus-
pected source. Adjust the regulator to the suitable
test pressure that provide the best bubbles which
will pinpoint the leak source. If the oil leak is de-
tected and identified, repair per service manual pro-
cedures.
(5) If the leakage occurs at the rear oil seal area,
refer to the section, Inspection for Rear Seal Area
Leak.
(6) If no leaks are detected, turn off the air supply
and remove the air hose and all plugs and caps. In-
stall the PCV valve and breather cap hose. Proceed
to step 7.
(7) Clean the oil off the suspect oil leak area using
a suitable solvent. Drive the vehicle at various
speeds approximately 24 km (15 miles). Inspect the
engine for signs of an oil leak by using a black light.
INSPECTION FOR REAR SEAL AREA LEAKS
Since it is sometimes difficult to determine the
source of an oil leak in the rear seal area of the en-
gine, a more involved inspection is necessary. The fol-
lowing steps should be followed to help pinpoint the
source of the leak.
If the leakage occurs at the crankshaft rear oil seal
area:
(1) Disconnect the battery.
(2) Raise the vehicle.
(3) Remove torque converter or clutch housing
cover and inspect rear of block for evidence of oil.
Use a black light to check for the oil leak:
(a) Circular spray pattern generally indicates
seal leakage or crankshaft damage.
(b) Where leakage tends to run straight down,
possible causes are a porous block, distributor seal,
camshaft bore cup plugs oil galley pipe plugs, oil
9 - 6 ENGINESJ
2.5L ENGINE SERVICE PROCEDURES
INDEX
page page
Camshaft............................... 32
Camshaft Pin Replacement.................. 34
Engine AssemblyÐXJ Vehicles............... 18
Engine AssemblyÐYJ Vehicles............... 20
Engine Cylinder Head...................... 25
Engine Cylinder Head Cover................. 22
Engine Damper........................... 17
Engine MountÐRear....................... 16
Engine MountsÐFront..................... 14
General Information....................... 13
Hydraulic Tappets......................... 24OilPan ................................. 36
Rocker Arms and Push Rods................ 23
Timing Case Cover........................ 31
Timing Case Cover Oil Seal Replacement....... 30
Timing Chain and Sprockets................. 31
Valve Component ReplaceÐCylinder Head Not
Removed.............................. 23
Valve Springs and Oil Seals................. 23
Valve Timing............................. 30
Valves and Valve Springs................... 27
Vibration Damper......................... 30
GENERAL INFORMATION
The 2.5 liter (150 CID) four-cylinder engine is an
In-line, lightweight, overhead valve engine (Fig. 1).
This engine is designed for unleaded fuel.
The engine cylinder head has dual quench-type
combustion chambers that create turbulence and fast
burning of the air/fuel mixture. This results in good
fuel economy.
The cylinders are numbered 1 through 4 from front
to rear. The firing order is 1-3-4-2 (Fig. 2).
The crankshaft rotation is clockwise, when viewed
from the front of the engine. The crankshaft rotates
within five main bearings and the camshaft rotates
within four bearings.
BUILD DATE CODE
The engine Build Date Code is located on a ma-
chined surface on the right side of the cylinder block
between the No.3 and No.4 cylinders (Fig. 3).
Fig. 1 Engine Description
Fig. 2 Engine Firing Order
Fig. 3 Build Date Code Location
J2.5L ENGINE 9 - 13