clock JEEP CHEROKEE 1994 Service Owner's Manual

UNDERHOOD LAMP BULB REPLACEMENT
REMOVALÐALL VEHICLES
(1) Disconnect the wire harness connector from the
underhood lamp.
(2) Rotate the bulb counter-clockwise and remove
it from the lamp base socket.
INSTALLATIONÐALL VEHICLES
(1) Insert a replacement bulb in the lamp base
socket and rotate it clockwise.
(2) Connect the wire harness connector to the
lamp.
UNDERHOOD LAMP REPLACEMENT
REMOVALÐALL VEHICLES
(1) Disconnect the wire harness connector from the
lamp.(2) Rotate the bulb counter-clockwise and remove
it from the lamp base socket.
(3) Remove the screw that attaches the lamp re-
flector and support bracket to the hood inner panel.
(4) Remove the lamp from the hood inner panel.
INSTALLATIONÐALL VEHICLES
(1) Position the underhood lamp on the hood inner
panel.
(2) Install the attaching screw through the lamp
and into the hood panel. Tighten the screw securely.
(3) Insert a replacement bulb in the lamp base
socket and rotate it clockwise.
(4) Connect the wire harness connector to the
lamp.
8L - 18 LAMPSJ

INTERIOR LAMPS
INDEX
page page
Dome Lamp Replacement.................. 20
Dome/Courtesy Lamp Service Information...... 19
Dome/Courtesy Lamp Trouble Diagnosis....... 19
Hardtop Dome/Cargo Lamp Bulb ReplacementÐYJ
Vehicles.............................. 20Illuminated Entry System Service Information . . . 20
Illuminated Entry System Trouble Diagnosis.... 21
Lighted Vanity Mirror...................... 19
Lighted Vanity Mirror Trouble Diagnosis....... 19
Overhead ConsoleÐXJ Vehicles............. 20
DOME/COURTESY LAMP SERVICE INFORMATION
XJ VEHICLES
Voltage is applied at all times via the dome lamp
fuse to each of the interior lamp bulbs. The interior
lamp bulbs illuminate when they are connected to
body ground via the switch:
²headlamp switch,
²glove box switch,
²door pillar switch, and
²liftgate switch (if the cargo lamp is ON.)
If equipped with Security Alarm Module, refer to
Group 8QÐVehicle Theft Security System.
YJ VEHICLES
The dome/cargo and courtesy lamps are controlled
via ON/OFF switches. The ON/OFF switches are in
the lamp ground circuits. Voltage via the dome/cour-
tesy lamp fuse is applied directly to the lamp bulbs.
When either door is opened, the door pillar switch
contacts close and provide a direct path to vehicle
body ground.
The cargo/cargo and courtesy lamps can also be
turned on via the interior lamp illumination rheo-
stat.
DOME/COURTESY LAMP TROUBLE DIAGNOSIS
ALL LAMPS INOPERATIVE
(1) Rotate the headlamp switch rheostat clockwise.
The lamps should light. If not OK, remove, inspect
and test the dome lamp fuse. Replace if bad.
(2) If the fuse is OK, repair the open circuit in the
wire harness to vehicle body ground.
ONE LAMP INOPERATIVE
(1) Measure the resistance across the bulb holder
terminals. The ohmmeter should indicate zero ohms.
If not, replace the bulb.
(2) Measure the voltage between the voltage side
of the bulb holder and vehicle body ground. The volt-
meter should indicate battery voltage. If not, repair
the open circuit in the wire harness to the splice.
LAMPS INOPERATIVE WITH ONE OR MORE
DOORS OPENED
(1) Remove the inoperative switch from the door
pillar and connect the switch wire directly to ground.
The lamp should light.
(2) If not, check for an open circuit in black
(ground) wire. Repair as necessary. If lamps still do
not light, replace the switch.
LIGHTED VANITY MIRROR
SERVICE INFORMATIONÐXJ VEHICLES
Both the driver and the front passenger sunvisor
can be equipped with a lighted vanity mirror. A
lamp located at each side of the vanity mirror. The
lamps are switched ON automatically when the mir-
ror cover is lifted (Fig. 1).
Voltage is applied directly to the vanity lamp bulbs
via the dome lamp fuse.
LIGHTED VANITY MIRROR TROUBLE DIAGNOSIS
VANITY LAMPS INOPERATIVE
(1) Remove, inspect and test the dome lamp fuse.
Replace if defective.
(2) Test the dome lamp operation. If OK, go to the
next step. If not OK, repair the open circuit in the
wire harness from the splice.
Fig. 1 Lighted Vanity Mirror
JLAMPS 8L - 19

WIRING DIAGRAMS YJ
ALPHABETICAL INDEX
Wiring Diagram Name Sheet Number
ABS Accelerator Sensor........................59
ABS Control Module.....................57, 58, 59
ABS Control Module Connector...................60
ABS Motor Pump Relay........................57
ABS Power Relay............................57
A/C Blower Switch............................50
A/C Compressor.............................49
A/C Low Pressure Switch.......................49
A/C Relay.................................49
A/C Thermostat..............................50
Accessory Illumination.........................32
Air Conditioning System (4.0L).................49, 50
A/C Blower Switch..........................50
A/C Compressor............................49
A/C Low Pressure Switch.....................49
A/C Relay................................49
A/C Thermostat............................50
Field Jumper..............................50
Powertrain Control Module.....................49
Anti-Lock Brake System (TEVES).............57, 58, 59
ABS Accelerator Sensor.......................59
ABS Control Module....................57, 58, 59
ABS Motor Pump Relay.......................57
ABS Power Relay...........................57
Brake Pedal Travel Sensor.....................57
Data Link Connector.........................57
Diode..................................58
Hydraulic Actuation Unit......................58
Left Front Wheel Sensor......................59
Left Rear Wheel Sensor.......................59
Power Distribution Center.....................57
Pump Motor..............................57
Pump Motor Sensor.........................57
Right Front Wheel Sensor.....................59
Right Rear Wheel Sensor......................59
Automatic Shut-Down Relay...................11, 17
Back-Up Lamps...........................51, 52
Back-Up Lamp Switch..........................7
Battery................................1,3,5
Blower Motor...............................47
Blower Resistor.............................47
Blower Switch..............................47
Body Harness Connector........................36
Brake Pedal Travel Sensor.......................57
Brake Warning Switch..........................9
Bulkhead Connector........................65, 66
Buzzer Module..............................36
Camshaft Position Sensor....................12, 18
Center High Mounted Stop Lamp..................52
Charging System 2.5L Engine...................3,4
Battery..................................3
Generator.................................3
Power Distribution Center......................4Wiring Diagram Name Sheet Number
Charging System 4.0L Engine...................5,6
Battery..................................5
Generator.................................5
Power Distribution Center......................6
Cigar Lighter...............................24
Circuit Breakers
Headlamp Switch.........................1,29
#11 (W/Wiper).....................2,10,38,39
Clock....................................45
Cluster Connector............................41
Crankshaft Position Sensor...................12, 18
Data Link Connector.....................13, 19, 57
Daytime Running Lamp Module...................28
Dimmer Switch............................1,29
Dome and Courtesy Lamps......................35
Dome Lamp..............................35
Left Courtesy Lamp.........................35
Left Front Door Jamb Switch...................35
Right Courtesy Lamp........................35
Right Front Door Jamb Switch..................35
Dome Lamp................................35
Electrically Tuned Radio with Clock.................45
Electrical Schematic of Cluster....................42
Electrical Schematic of Gauge Package..............44
Electronic Speedometer.........................42
Electronic Tachometer..........................42
Engine Coolant Temp Gauge.....................44
Engine Coolant Temperature Sensor..............15, 21
Engine Oil Pressure and Temperature System..........23
Engine Coolant Temperature Sending Unit...........23
Engine Oil Pressure Sending Unit................23
Engine Oil Pressure Gauge......................44
Engine Starter System........................2,7
Back-Up Lamp Switch........................7
Engine Starter Motor.........................7
Engine Starter Relay..........................7
Park/Neutral Position Switch....................7
Engine Wiring Connector (16 Way).................69
4-WD Command Trac Switch......................8
Field Jumper...............................50
Fog Lamp Relays............................30
Fog Lamp Switch............................30
Front End Lighting.........................25, 26
Left Fog Lamp.............................25
Left Headlamp.............................25
Left Park and Turn Signal Lamp.................25
Left Side Marker Lamp.......................25
Right Fog Lamp............................26
Right Headlamp............................26
Right Park and Turn Signal Lamp................26
Right Side Marker Lamp......................26
Front End Lighting (Canada)...................27, 28
Daytime Running Lamp Module.................28
JWIRING DIAGRAMS 8W - 73

Wiring Diagram Name Sheet Number
Left Back-Up Lamp..........................51
Left Courtesy Lamp.........................35
Left Fog Lamp..........................25, 27
Left Headlamp..........................25, 27
Left Park and Turn Signal Lamp..............25, 27
Left Side Marker Lamp....................25, 27
Left Tail, Stop and Turn Signal Lamp..............51
Right Back-Up Lamp.........................52
Right Courtesy Lamp........................35
Right Fog Lamp.........................26, 28
Right Headlamp.........................26, 28
Right Park and Turn Signal Lamp.............26, 28
Right Side Marker Lamp...................26, 28
Right Tail, Stop and Turn Signal Lamp.............52
Underhood Lamp............................8
Left Back-Up Lamps..........................51
Left Courtesy Lamp...........................35
Left Fog Lamp...........................25, 27
Left Front Door Jamb Switch.....................35
Left Front Speaker............................46
Left Halo Speaker............................46
Left Headlamp............................25, 27
Left Park and Turn Signal Lamp................25, 27
Left Side Marker Lamp......................25, 27
Left Tail, Stop and Turn Signal Lamp...............51
MAP Sensor.............................15, 21
Mercury Switch..............................8
Modules
ABS Control Module....................57, 58, 59
Buzzer Module.............................36
Daytime Running Lamp Module.................28
Intermittent Wiper Module.....................40
Motors
Blower Motor.............................47
Engine Starter Motor.........................7
Idle Air Control Motor.....................14, 20
Rear Wiper Motor..........................37
Wiper Motor...........................38, 39
Oil Pressure and Temp System...................23
Panel Lamp Dimmer Switch......................1
Panel Lamps.............................31, 32
Accessory Illumination........................32
Heater Control Panel Illumination.................32
Panel Lamp Dimmer Switch....................31
Transmission Range Illumination.................32
Park Brake Switch.............................9
Park/Neutral Position Switch......................7
Part Throttle EMCC 3-Speed Automatic Transmission.....56
Part Throttle EMCC Relay.......................56
Part Throttle EMCC Solenoid.....................56
Power Distribution Center.................1,4,6,57
Power Distribution Center Identification Cover..........67
Power Distribution Center Relays..................68
Power Steering Switch.........................14
Powertrain Control Module............11-22, 48, 49, 56
Powertrain Control Module Connector (2.5L Engine)......63
Powertrain Control Module Connector (4.0L Engine)......64
Provisions for A/C (2.5L).......................48Wiring Diagram Name Sheet Number
Radio Illumination Relay........................45
Radio System............................45, 46
Electrically Tuned Radio with Clock...............45
Left Front Speaker..........................46
Left Halo Speaker...........................46
Radio Illumination Relay......................45
Right Front Speaker.........................46
Right Halo Speaker..........................46
Rear Lighting............................51, 52
Center High Mounted Stop Lamp................52
Left Back-Up Lamp..........................51
Left Tail, Stop & Turn Signal Lamp & License Lamp....51
Right Back-Up Lamp.........................52
Right Tail, Stop & Turn Signal Lamp..............52
Rear Wiper/Washer System......................37
Rear Wiper Motor..........................37
Rear Wiper Switch..........................37
Washer Pump.............................37
Relays
A/C ....................................49
ABS Motor Pump Relay.......................57
ABS Power Relay...........................57
Automatic Shut Down Relay.................11, 17
EMCC...................................56
Engine Starter Relay..........................7
Fog Lamp Relays...........................30
Fuel Pump Relay........................11, 17
Heated Rear Window Relay....................54
Horn Relay...............................33
Radio Illumination Relay......................45
Right Back-Up Lamp..........................52
Right Courtesy Lamp..........................35
Right Fog Lamp...........................26, 28
Right Front Door Jamb Switch....................35
Right Front Speaker...........................46
Right Halo Speaker...........................46
Right Headlamp...........................26, 28
Right Park and Turn Signal...................26, 28
Right Side Marker Lamp.....................26, 28
Right Tail, Stop and Turn Signal Lamp..............52
Seat Belt/Ignition Key Warning Buzzer...............36
Seat Belt Switch.............................36
Sensors
ABS Accelerator Sensor.......................59
Brake Pedal Travel Sensor.....................57
Camshaft Position Sensor...................12, 18
Crankshaft Position Sensor..................12, 18
Engine Coolant Temperature Sensor............15, 21
Heated Oxygen Sensor.....................11, 17
Intake Air Temperature Sensor................15, 21
MAP Sensor...........................15, 21
Pump Motor Sensor.........................57
Throttle Position (Sensor)...................15, 21
Vehicle Speed Sensor.....................12, 18
Wheel Sensors............................59
Speakers..................................46
Speedometer...............................42
JWIRING DIAGRAMS 8W - 75

2.5L ENGINE SERVICE PROCEDURES
INDEX
page page
Camshaft............................... 29
Camshaft Pin Replacement................. 31
Crankshaft Main Bearings.................. 40
Cylinder Block........................... 45
Engine AssemblyÐXJ Vehicles.............. 14
Engine AssemblyÐYJ Vehicles.............. 16
Engine Cylinder Head..................... 19
Engine Cylinder Head Cover................ 18
Engine Damper.......................... 13
Engine MountÐRear...................... 12
Engine MountsÐFront..................... 10
General Information........................ 9
Hydraulic Tappets........................ 24Oil Pan ................................ 32
Oil Pump............................... 33
Pistons and Connecting Rods............... 34
Rear Main Oil Seals...................... 44
Rocker Arms............................ 19
Specifications........................... 47
Timing Case Cover....................... 27
Timing Case Cover Oil Seal Replacement...... 26
Timing Chain and Sprockets................ 28
Valve Springs and Oil Seals................ 21
Valve Timing............................ 26
Valves and Valve Springs.................. 22
Vibration Damper........................ 26
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 - 9

a time, to avoid damaging the bridges.
(3) Remove the push rods.
(4) Remove the tappets through the push rod open-
ings in the cylinder head with Hydraulic Valve Tap-
pet Removal/Installation Tool C-4129-A (Fig. 13).
CLEANING
Clean each tappet assembly in cleaning solvent to
remove all varnish, gum and sludge deposits.
INSPECTION
Inspect for indications of scuffing on the side and
base of each tappet body.
Inspect each tappet base for concave wear with a
straightedge positioned across the base. If the base is
concave, the corresponding lobe on the camshaft is
also worn. Replace the camshaft and defective tap-
pets.
LEAK-DOWN TEST
After cleaning and inspection, test each tappet for
specified leak-down rate tolerance to ensure zero-lash
operation (Fig. 14).
Swing the weighted arm of the hydraulic valve tap-
pet tester away from the ram of the Leak-Down
Tester 7980.
(1) Place a 7.925-7.950 mm (0.312-0.313 inch) di-
ameter ball bearing on the plunger cap of the tappet.
(2) Lift the ram and position the tappet (with the
ball bearing) inside the tester cup.
(3) Lower the ram, then adjust the nose of the ram
until it contacts the ball bearing. DO NOT tighten
the hex nut on the ram.
(4) Fill the tester cup with hydraulic valve tappet
test oil until the tappet is completely submerged.(5) Swing the weighted arm onto the push rod and
pump the tappet plunger up and down to remove air.
When the air bubbles cease, swing the weighted arm
away and allow the plunger to rise to the normal po-
sition.
(6) Adjust the nose of the ram to align the pointer
with the SET mark on the scale of the tester and
tighten the hex nut.
(7) Slowly swing the weighted arm onto the push
rod.
(8) Rotate the cup by turning the handle at the
base of the tester clockwise one revolution every 2
seconds.
(9) Observe the leak-down time interval from the
instant the pointer aligns with the START mark on
the scale until the pointer aligns with the 0.125
mark. A normally functioning tappet will require 20-
110 seconds to leak-down. Discard tappets with leak-
down time interval not within this specification.
INSTALLATION
It is not necessary to charge the tappets with en-
gine oil. They will charge themselves within a very
short period of engine operation.
(1) Dip each tappet in Mopar Engine Oil Supple-
ment, or equivalent.
(2) Use Hydraulic Valve Tappet Removal/Installa-
tion Tool C-4129-A to install each tappet in the same
bore from where it was originally removed.
(3) Install the push rods in their original locations.
(4) Install the rocker arms and bridge and pivot
assemblies at their original locations. Loosely install
the capscrews at each bridge.
(5) Tighten the capscrews alternately, one turn at
a time, to avoid damaging the bridges. Tighten the
capscrews to 28 Nzm (21 ft. lbs.) torque.
(6) Pour the remaining Mopar Engine Oil Supple-
ment, or equivalent over the entire valve actuating
assembly. The Mopar Engine Oil Supplement, or
equivalent must remain with the engine oil for at
Fig. 13 Hydraulic Valve Tappet Removal/Installation
Tool C-4129-A
Fig. 14 Leak-Down Tester 7980
J2.5L ENGINE 9 - 25

least 1 600 km (1,000 miles). The oil supplement
need not be drained until the next scheduled oil
change.
(7) Install the engine cylinder head cover.
VALVE TIMING
Disconnect the spark plug wires and remove the
spark plugs.
Remove the engine cylinder head cover.
Remove the capscrews, bridge and pivot assembly,
and rocker arms from above the No.1 cylinder.
Alternately loosen each capscrew, one turn at a
time, to avoid damaging the bridge.
Rotate the crankshaft until the No.4 piston is at
top dead center (TDC) on the compression stroke.
Rotate the crankshaft counterclockwise (viewed
from the front of the engine) 90É.
Install a dial indicator on the end of the No.1 cyl-
inder intake valve push rod. Use rubber tubing to se-
cure the indicator stem on the push rod.
Set the dial indicator pointer at zero.
Rotate the crankshaft clockwise (viewed from the
front of the engine) until the dial indicator pointer
indicates 0.305 mm (0.012 inch) travel distance (lift).
The timing notch index on the vibration damper
should be aligned with the TDC mark on the timing
degree scale.
If the timing notch is more than 13 mm (1/2 inch)
away from the TDC mark in either direction, the
valve timing is incorrect.
If the valve timing is incorrect, the cause may be a
broken camshaft pin. It is not necessary to replace
the camshaft because of pin failure. A spring pin is
available for service replacement.
VIBRATION DAMPER
REMOVAL
(1) Disconnect negative cable from battery.
(2) Remove the serpentine drive belt and fan
shroud.
(3) Remove the vibration damper retaining bolt
and washer.
(4) Use Vibration Damper Removal Tool 8068 to
remove the damper from the crankshaft (Fig. 1).
INSTALLATION
(1) Apply Mopar Silicone Rubber Adhesive Sealant
to the keyway in the crankshaft and insert the key.
With the key in position, align the keyway on the vi-
bration damper hub with the crankshaft key and tap
the damper onto the crankshaft.
(2) Install the vibration damper retaining bolt and
washer.
(3) Tighten the damper retaining bolt to 108 Nzm
(80 ft. lbs.) torque.(4) Install the serpentine drive belt and tighten to
the specified tension (refer to Group 7, Cooling Sys-
tems for the proper specifications and procedures).
(5) Connect negative cable to battery.
TIMING CASE COVER OIL SEAL REPLACEMENT
This procedure is done with the timing case cover
installed.
(1) Disconnect negative cable from battery.
(2) Remove the serpentine drive belt.
(3) Remove the vibration damper.
(4) Remove the radiator shroud.
(5) Carefully remove the oil seal (Fig. 2). Make
sure seal bore is clean.
(6) Position the replacement oil seal on Timing
Case Cover Alignment and Seal Installation Tool
6139 with seal open end facing inward. Apply a light
film of Perfect Seal, or equivalent, on the outside di-
ameter of the seal. Lightly coat the crankshaft with
engine oil.
(7) Position the tool and seal over the end of the
crankshaft and insert a draw screw tool into Seal In-
stallation Tool 6139 (Fig. 3). Tighten the nut against
the tool until it contacts the cover.
Fig. 1 Vibration Damper Removal Tool 8068
Fig. 2 Timing Case Cover Oil Seal Removal
9 - 26 2.5L ENGINEJ

(12) Properly position the distributor rotor as fol-
lows:
(a) Remove No.1 spark plug. Hold your finger
over the spark plug hole and rotate the crankshaft
until compression pressure is felt. Slowly continue
to rotate the crankshaft until the timing index on
the vibration damper aligns with the top dead cen-
ter (TDC) mark (0É on the timing degree scale).Al-
ways rotate the crankshaft clockwise (the
direction of normal rotation). DO NOT rotate
the crankshaft backward to align the timing
marks.
(b) Rotate the oil pump gear so that the gear slot
on the oil pump shaft is slightly past the 3 o'clock
position (Fig. 12). A flat blade screwdriver can be
used to rotate the gear.
(c) Turn the distributor shaft until the rotor tip
points in the direction of No.1 terminal in the dis-
tributor cap. Turn the rotor 1/8 turn counterclock-
wise past the position of No.1 terminal.
(d) With the distributor cap removed, start the
distributor into the cylinder block with the rotor lo-
cated at the 5 o'clock position (Fig. 13).
(e) Slide the distributor shaft down into the en-
gine. Position the distributor vacuum advance
mechanism housing in approximately the same lo-
cation as when removed. Align the scribe mark onthe distributor housing with the corresponding
scribe mark on the cylinder block. The rotor should
align with the position of No.1 terminal when the
distributor shaft is down in place. It may be neces-
sary to rotate the oil pump shaft with a long flat-
blade screwdriver to engage the oil pump drive
tang.
(f) Install the distributor holddown clamp and
bolt. DO NOT tighten the bolt.
(g) When the distributor is fully engaged in its
correct location, the rotor should be at the 6 o'clock
position (Fig. 14).
(h) If the distributor is not properly installed, or
if it is removed later, then the complete installa-
tion procedures must be repeated.
(13) Install the radiator or radiator/condenser, if
equipped with A/C.
(14) Fill the cooling system.
(15) Connect negative cable to battery.
Fig. 11 Timing Case Cover
Fig. 12 Oil Pump Gear Slot Alignment
Fig. 13 Distributor Rotor Pre-Positioning
Fig. 14 Correct Rotor Position
9 - 30 2.5L ENGINEJ

4.0L ENGINE SERVICE PROCEDURES
INDEX
page page
Camshaft............................... 69
Camshaft Pin Replacement................. 71
Crankshaft Main Bearings.................. 80
Cylinder Block........................... 85
Engine AssemblyÐXJ Vehicles.............. 54
Engine AssemblyÐYJ Vehicles.............. 57
Engine Cylinder Head..................... 60
Engine Cylinder Head Cover................ 59
Engine MountÐRear...................... 52
Engine MountsÐFront..................... 51
General Information....................... 50
Hydraulic Tappets........................ 65
Oil Pan ................................ 72Oil Pump............................... 73
Pistons and Connecting Rods............... 74
Rear Main Oil Seals...................... 84
Rocker Arms............................ 59
Specifications........................... 87
Timing Case Cover....................... 67
Timing Case Cover Oil Seal Replacement...... 67
Timing Chain and Sprockets................ 68
Valve Springs and Oil Seals................ 62
Valve Timing............................ 66
Valves and Valve Springs.................. 63
Vibration Damper........................ 67
GENERAL INFORMATION
The 4.0 Liter (242 CID) six-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 6 from front
to rear. The firing order is 1-5-3-6-2-4 (Fig. 2).The crankshaft rotation is clockwise, when viewed
from the front of the engine. The crankshaft rotates
within seven main bearings. 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.2 and No.3 cylinders (Fig. 3).
The digits of the code identify:
(1) 1st DigitÐThe year (4 = 1994).
(2) 2nd & 3rd DigitsÐThe month (01 - 12).
(3) 4th & 5th DigitsÐThe engine type/fuel system/
compression ratio (MX = A 4.0 Liter (242 CID) 8.7:1
compression ratio engine with a multi-point fuel in-
jection system).
(4) 6th & 7th DigitsÐThe day of engine build (01 -
31).
FOR EXAMPLE:Code * 401MX12 * identifies a
4.0 liter (242 CID) engine with a multi-point fuel in-
jection system, 8.7:1 compression ratio and built on
January 12, 1994.
Fig. 2 Engine Firing Order
Fig. 1 Engine Description
9 - 50 4.0L ENGINEJ

LEAK-DOWN TEST
After cleaning and inspection, test each tappet for
specified leak-down rate tolerance to ensure zero-lash
operation (Fig. 12).
Swing the weighted arm of the hydraulic valve tap-
pet tester away from the ram of the Leak-Down
Tester 7980.
(1) Place a 7.925-7.950 mm (0.312-0.313 inch) di-
ameter ball bearing on the plunger cap of the tappet.
(2) Lift the ram and position the tappet (with the
ball bearing) inside the tester cup.
(3) Lower the ram, then adjust the nose of the ram
until it contacts the ball bearing. DO NOT tighten
the hex nut on the ram.
(4) Fill the tester cup with hydraulic valve tappet
test oil until the tappet is completely submerged.
(5) Swing the weighted arm onto the push rod and
pump the tappet plunger up and down to remove air.
When the air bubbles cease, swing the weighted arm
away and allow the plunger to rise to the normal po-
sition.
(6) Adjust the nose of the ram to align the pointer
with the SET mark on the scale of the tester and
tighten the hex nut.
(7) Slowly swing the weighted arm onto the push
rod.
(8) Rotate the cup by turning the handle at the
base of the tester clockwise one revolution every 2
seconds.
(9) Observe the leak-down time interval from the
instant the pointer aligns with the START mark on
the scale until the pointer aligns with the 0.125
mark. A normally functioning tappet will require 20-
110 seconds to leak-down. Discard tappets with leak-
down time interval not within this specification.
INSTALLATION
It is not necessary to charge the tappets with en-
gine oil. They will charge themselves within a very
short period of engine operation.(1) Dip each tappet in Mopar Engine Oil Supple-
ment, or equivalent.
(2) Use Hydraulic Valve Tappet Removal/Installa-
tion Tool C-4129-A to install each tappet in the same
bore from where it was originally removed.
(3) Install the exhaust and intake manifolds (refer
to Group 11, Exhaust System and Intake Manifold
for the proper procedure).
(4) Install the engine cylinder head and gasket.
(5) Install the push rods in their original locations.
(6) Install the rocker arms and bridge and pivot
assemblies at their original locations. Loosely install
the capscrews at each bridge.
(7) Tighten the capscrews alternately, one turn at
a time, to avoid damaging the bridges. Tighten the
capscrews to 28 Nzm (21 ft. lbs.) torque.
(8) Pour the remaining Mopar Engine Oil Supple-
ment, or equivalent over the entire valve actuating
assembly. The Mopar Engine Oil Supplement, or
equivalent must remain with the engine oil for at
least 1 609 km (1,000 miles). The oil supplement
need not be drained until the next scheduled oil
change.
(9) Install the engine cylinder head cover.
VALVE TIMING
Disconnect the spark plug wires and remove the
spark plugs.
Remove the engine cylinder head cover.
Remove the capscrews, bridge and pivot assembly,
and rocker arms from above the No.1 cylinder.
Alternately loosen each capscrew, one turn at a
time, to avoid damaging the bridge.
Rotate the crankshaft until the No.6 piston is at
top dead center (TDC) on the compression stroke.
Rotate the crankshaft counterclockwise (viewed
from the front of the engine) 90É.
Install a dial indicator on the end of the No.1 cyl-
inder intake valve push rod. Use rubber tubing to se-
cure the indicator stem on the push rod.
Set the dial indicator pointer at zero.
Rotate the crankshaft clockwise (viewed from the
front of the engine) until the dial indicator pointer
indicates 0.305 mm (0.012 inch) travel distance (lift).
The timing notch index on the vibration damper
should be aligned with the TDC mark on the timing
degree scale.
If the timing notch is more than 13 mm (1/2 inch)
away from the TDC mark in either direction, the
valve timing is incorrect.
If the valve timing is incorrect, the cause may be a
broken camshaft pin. It is not necessary to replace
the camshaft because of pin failure. A spring pin is
available for service replacement.
Fig. 12 Leak-Down Tester 7980
9 - 66 4.0L ENGINEJ