Intake Air temperature JEEP GRAND CHEROKEE 2002 WJ / 2.G User Guide

POWER CONNECTOR - WHITE 2 WAY
CAV CIRCUIT FUNCTION
1 F85 16VT/WT FUSED B(+)
2 Z234 16BK GROUND
POWERTRAIN CONTROL MODULE C1 (GAS) - BLACK 32 WAY
CAV CIRCUIT FUNCTION
1 K93 14TN/OR COIL DRIVER NO. 3
2 F991 18OR/DB FUSED IGNITION SWITCH OUTPUT (RUN-START)
3 K94 14TN/LG (4.7L) COIL DRIVER NO. 4
4 K4 18BK/LB SENSOR GROUND
5 K96 14TN/LB (4.7L) COIL DRIVER NO. 6
6 T41 18BK/WT PARK/NEUTRAL POSITION SWITCH SENSE (T41)
7 K91 14TN/RD COIL DRIVER NO. 1
8 K24 18GY/BK CRANKSHAFT POSITION SENSOR SIGNAL
9 K98 14LB/RD (4.7L) COIL DRIVER NO. 8
10 K60 18YL/BK IDLE AIR CONTROL NO. 2 DRIVER
11 K40 18BR/WT IDLE AIR CONTROL NO. 3 DRIVER
12 - -
13 - -
14 K77 18LG/BK TRANSFER CASE POSITION SENSOR INPUT
15 K21 18BK/RD INTAKE AIR TEMPERATURE SENSOR SIGNAL
16 K2 18TN/BK ENGINE COOLANT TEMPERATURE SENSOR SIGNAL
17 K7 18OR 5 VOLT SUPPLY
18 K44 18TN/YL CAMSHAFT POSITION SENSOR SIGNAL
19 K39 18GY/BK IDLE AIR CONTROL NO. 1 DRIVER
20 K59 18VT/BK IDLE AIR CONTROL NO. 4 DRIVER
21 K95 14TN/DG (4.7L) COIL DRIVER NO. 5
22 A7 14RD/BK FUSED B(+)
23 K22 18OR/RD THROTTLE POSITION SENSOR SIGNAL
24 K41 18BK/DG OXYGEN SENSOR 1/1 SIGNAL
25 K141 18TN/WT OXYGEN SENSOR 1/2 SIGNAL
26 K241 18LG/RD (EXCEPT 4.0L
BUILT-UP-EXPORT)OXYGEN SENSOR 2/1 SIGNAL
27 K1 18DG/RD MAP SENSOR SIGNAL
28 - -
29 K341 18TN/WT (4.0L EXCEPT
BUILT-UP-EXPORT)OXYGEN SENSOR 2/2 SIGNAL
29 K341 18PK/WT (4.7L) OXYGEN SENSOR 2/2 SIGNAL
30 - -
31 Z82 14BK/WT GROUND
32 Z81 14BK/TN GROUND
8W - 80 - 108 8W-80 CONNECTOR PIN-OUTWJ

CONNECTOR NAME/
NUMBERCOLOR LOCATION FIG.
Fuel Pump Module (Gas) BK Near Fuel Tank 33, 35
Fuel Tank Module Diesel) BK Near Fuel Tank 33, 35
Generator (Diesel) LTGY At Generator 8
Generator (Gas) BK At Generator N/S
Glove Box Lamp BK Inside Glove Box 19, 20, 22
Headlamp Leveling Switch
(Built-Up-Export)WT Driver Side of Instrument Panel 20
Hood Ajar Switch BK Left Side of Engine Compartment 3, 4
Horn No.1 BK Right Front Fascia 5
Horn No.2 BK Right Front Fascia 5
Hydraulic Cooling Module BK Right Front of Engine Compartment 5
Idle Air Control Motor BK Left Side of Engine Near Throttle
Body13
Ignition Switch - C1 WT On Steering Column 23
Ignition Switch - C2 BK On Steering Column 23
Input Speed Sensor (4.7L) BK Left Side of Transmission 16
Instrument Cluster WT At Instrument Cluster 19, 20
Intake Air Temperature Sensor
(Gas)GY Left Side of Engine 9, 13
Intake Air Temperature Sensor
(Diesel)BK Near T/O for Crankcase Heater 8
Intake Port Swirl Actuator
(Diesel)BK Right Rear of Engine Compartment N/S
Intrusion Transceiver Module
(Built-up-Export)BK In The Overhead N/S
Junction Block - C1 BK At Junction Block 30, 31, 33
Junction Block - C2 BK At Junction Block 30, 31
Junction Block - C3 BK At Junction Block 21, 22, 30
Junction Block - C4 WT At Junction Block 30, 31
Junction Block - C5 WT At Junction Block 30, 31
Knock Sensor (4.7L High
Output)BK Right Rear Side of Engine, Near
Coil on Plug No.8N/S
Leak Detection Pump (Except
Built-Up-Export)Left Front Wheel Opening 3
Left Courtesy Lamp BK Left Side of Instrument Panel 21 22, 23
Left Curtain Airbag BK Near Left C Pillar 37
Left Door Handle Courtesy
LampBK At Lamp N/S
Left Fog Lamp BK At Lamp 3, 4
Left Front Door Speaker WT In Left Front Door 24, 27
Left Front Impact Sensor BK Left Front Frame Near Windshield
Washer Pump3, 4
Left Front Park Lamp WT At Lamp N/S
8W - 91 - 6 8W-91 CONNECTOR/GROUND/SPLICE LOCATIONWJ
CONNECTOR/GROUND/SPLICE LOCATION (Continued)

SPLICE
NUMBERLOCATION FIG.
S147 (Diesel) In T/O for Controller Anti-Lock Brake 4
S151 In Headlamp Assembly N/S
S152 In Headlamp Assembly N/S
S153 In Headlamp Assembly N/S
S154 In Headlamp Assembly N/S
S155 In Headlamp Assembly N/S
S156 In Headlamp Assembly N/S
S158 4.7L RHD Near T/O for Fuel Injector No. 1 13
S159 In T/O for C101 N/S
S160 (4.7L High
Output)In T/O for C102 N/S
S162 (Diesel) In T/O for Wastegate Solenoid 4, 8
S163 Near T/O for Leak Detection Pump 3
S165 (Diesel) Near T/O for Left Front Wheel Speed Sensor 4
S168 Near T/O for Intake Air Temperature Sensor 7, 8
S169 Near T/O for Engine Control Module C1 7, 8
S170 Near T/O for Engine Control Module C2 7, 8
S171 Near T/O for C113 7
S172 Near T/O for C113 7
S174 Near Washer Fluid Level Switch Connector 3
S176 Near T/O for Intake Air Temperature Sensor 7
S200 In Trough Near T/O for Passenger Heated Seat Switch 21
S200 (RHD) Upper Center Instrument Panel 22
S201 In Trough Near T/O for Front Power Outlet 21
S201 (RHD) Near T/O for Power Connector 22
S202 In Trough Near T/O for Passenger Heated Seat Switch 21
S202 (RHD) Upper Center Instrument Panel 22
S203 In Trough Near T/O for Cigar Lighter 21
S203 (RHD) Lower Center Instrument Panel 22
S204 In Trough Near T/O for Power Connector 21
S204 (RHD) Right Center Instrument Panel 22
S205 Near T/O for Adjustable Pedal Switch 21
S205 (RHD) Upper Center Instrument Panel 22
S206 Near T/O for Adjustable Pedals Switch N/S
S206 (RHD) Upper Center Instrument Panel 22
S207 In Trough Near T/O for Radio Connectors 21
S207 (RHD) Upper Center Instrument Panel 22
S208 In Trough Near T/O for Radio Connectors 21
S208 (RHD) Upper Center Instrument Panel 22
S209 In Trough Near T/O for Left Courtesy Lamp 21
S209 (RHD) Lower Center Instrument Panel 22
S210 In Trough Near T/O for Left Courtesy Lamp 21
8W - 91 - 14 8W-91 CONNECTOR/GROUND/SPLICE LOCATIONWJ
CONNECTOR/GROUND/SPLICE LOCATION (Continued)

DIAGNOSIS AND TESTINGÐCYLINDER
COMPRESSION PRESSURE
The results of a cylinder compression pressure test
can be utilized to diagnose several engine malfunc-
tions.
Ensure the battery is completely charged and the
engine starter motor is in good operating condition.
Otherwise, the indicated compression pressures may
not be valid for diagnosis purposes.
(1) Clean the spark plug recesses with compressed
air.
(2) Remove the spark plugs (Refer to 8 - ELEC-
TRICAL/IGNITION CONTROL/SPARK PLUG -
REMOVAL).
(3) Secure the throttle in the wide-open position.
(4) Disconnect the ignition coil.
(5) Insert a compression pressure gauge and rotate
the engine with the engine starter motor for three
revolutions.
(6) Record the compression pressure on the third
revolution. Continue the test for the remaining cylin-
ders.
(Refer to 9 - ENGINE - SPECIFICATIONS) for the
correct engine compression pressures.
DIAGNOSIS AND TESTING - CYLINDER
COMBUSTION PRESSURE LEAKAGE
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
jacket²Any causes for combustion/compression pressure
loss
WARNING: DO NOT REMOVE THE RADIATOR CAP
WITH THE SYSTEM HOT AND UNDER PRESSURE.
SERIOUS BURNS FROM HOT 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 OFF the
engine.
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 procedure on each cylinder accord-
ing to the tester manufacturer's instructions. While
testing, listen for pressurized air escaping through
the throttle body, tailpipe or 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 CYLINDER COMBUSTION
PRESSURE LEAKAGE DIAGNOSIS CHART .
CYLINDER COMBUSTION PRESSURE LEAKAGE DIAGNOSIS CHART
CONDITION POSSIBLE CAUSE CORRECTION
AIR ESCAPES THROUGH
THROTTLE BODYIntake valve bent, burnt, or not
seated properlyInspect valve and valve seat.
Reface or replace, as necessary
AIR ESCAPES THROUGH
TAILPIPEExhaust valve bent, burnt, or not
seated properlyInspect valve and valve seat.
Reface or replace, as necessary
AIR ESCAPES THROUGH
RADIATORHead gasket leaking or cracked
cylinder head or blockRemove cylinder head and inspect.
Replace defective part
MORE THAN 50% LEAKAGE
FROM ADJACENT CYLINDERSHead gasket leaking or crack in
cylinder head or block between
adjacent cylindersRemove cylinder head and inspect.
Replace gasket, head, or block as
necessary
MORE THAN 25% LEAKAGE AND
AIR ESCAPES THROUGH OIL
FILLER CAP OPENING ONLYStuck or broken piston rings;
cracked piston; worn rings and/or
cylinder wallInspect for broken rings or piston.
Measure ring gap and cylinder
diameter, taper and out-of-round.
Replace defective part as necessary
9 - 8 ENGINE - 4.0LWJ
ENGINE - 4.0L (Continued)

(7) Remove the fan assembly from the water pump
(Refer to 7 - COOLING/ENGINE/RADIATOR FAN -
REMOVAL).
(8) Remove the fan shroud.
(9) Disconnect the transmission fluid cooler lines
(automatic transmission).
(10) Discharge the A/C system (Refer to 24 -
HEATING & AIR CONDITIONING/PLUMBING -
STANDARD PROCEDURE).
(11) Remove the service valves and cap the com-
pressor ports.
(12) Remove the radiator or radiator/condenser (if
equipped with A/C).
(13) Disconnect the heater hoses at the engine
thermostat housing and water pump.
(14) Disconnect the accelerator cable, transmission
line pressure cable and speed control cable (if
equipped) from the throttle body.
(15) Remove cables from the bracket and secure
out of the way.
(16) Disconnect the body ground at the engine.
(17) Disconnect the following connectors and
secure their harness out of the way.
²Power steering pressure switch
²Coolant temperature sensor
²Six (6) fuel injector connectors
²Intake air temperature sensor
²Throttle position sensor
²Map sensor
²Crankshaft position sensor
²Oxygen sensor
²Camshaft position sensor
²Generator connector and B+ terminal wire
(18) Disconnect the coil rail electrical connections
and the oil pressure switch connector.
(19) Perform the fuel pressure release procedure
(Refer to 14 - FUEL SYSTEM/FUEL DELIVERY -
STANDARD PROCEDURE).
(20) Disconnect the fuel supply line at the injector
rail (Refer to 14 - FUEL SYSTEM/FUEL DELIVERY/
QUICK CONNECT FITTING - STANDARD PROCE-
DURE).
(21) Remove the fuel line bracket from the intake
manifold.
(22) Remove the air cleaner assembly (Fig. 5).
(23) Disconnect the hoses from the fittings at the
steering gear.
(24) Drain the pump reservoir.
(25) Cap the fittings on the hoses and steering
gear to prevent foreign objects from entering the sys-
tem.
(26) Raise and support the vehicle.
(27) Disconnect the wires from the engine starter
motor solenoid.(28) Remove the engine starter motor (Refer to 8 -
ELECTRICAL/STARTING/STARTER MOTOR -
REMOVAL).
(29) Disconnect the oxygen sensor from the
exhaust pipe.
(30) Disconnect the exhaust pipe from the mani-
fold.
(31) Remove the exhaust pipe support.
(32) Remove the bending brace (Refer to 9 -
ENGINE/ENGINE BLOCK/STRUCT SUPPORT -
REMOVAL).
(33) Remove the engine flywheel/converter housing
access cover.
(34) Mark the converter and drive plate location.
(35) Remove the converter-to-drive plate bolts.
(36) Remove the upper engine flywheel/converter
housing bolts and loosen the bottom bolts.
(37) Remove the engine mount cushion-to-engine
compartment bracket bolts.
(38) Lower the vehicle.
(39) Attach a lifting device to the engine.
(40) Raise the engine off the front supports.
(41) Place a support or floor jack under the con-
verter (or engine flywheel) housing.
(42) Remove the remaining converter (or engine
flywheel) housing bolts.
(43) Lift the engine out of the engine compart-
ment.
Fig. 5 Air Cleaner Assembly
1 - POWER STEERING PUMP
2 - AIR CLEANER ASSEMBLY
9 - 12 ENGINE - 4.0LWJ
ENGINE - 4.0L (Continued)

INSTALLATION
CAUTION: When installing the engine into a vehicle
equipped with an automatic transmission, be care-
ful not to damage the trigger wheel on the engine
flywheel.
(1) Attach a lifting device to the engine and lower
the engine into the engine compartment. For easier
installation, it may be necessary to remove the
engine mount bracket as an aid in alignment of the
engine to the transmission.
(2) Align the transmission torque converter hous-
ing with the engine.
(3) Loosely install the converter housing lower
bolts and install the next higher bolt and nut on each
side.
(4) Tighten all 4 bolts finger tight.
(5) Install the engine mount brackets (if removed).
(6) Lower the engine and engine mount brackets
onto the engine compartment cushions. Install the
bolts and finger tighten the nuts.
(7) Remove the engine lifting device.
(8) Raise and support the vehicle.
(9) Install the remaining engine flywheel/converter
housing bolts. Tighten all bolts to 38 N´m (28 ft. lbs.)
torque.
(10) Install the converter-to-drive plate bolts.
(11) Ensure the installation reference marks are
aligned.
(12) Install the engine flywheel/converter housing
access cover.
(13) Install the exhaust pipe support and tighten
the screw.
(14) Install the engine bending brace (Refer to 9 -
ENGINE/ENGINE BLOCK/STRUCT SUPPORT -
INSTALLATION).
(15) Tighten the engine mount-to-bracket bolts.
(16) Connect the vehicle speed sensor wire connec-
tions and tighten the screws.
(17) Connect the exhaust pipe to the manifold.
(18) Install the engine starter motor (Refer to 8 -
ELECTRICAL/STARTING/STARTER MOTOR -
INSTALLATION).
(19) Connect the wires to the engine starter motor
solenoid.
(20) Lower the vehicle.
(21) Connect all the vacuum hoses and wire con-
nectors identified during engine removal.
(22) Remove protective caps from the power steer-
ing hoses.
(23) Connect the hoses to the fittings at the steer-
ing gear. Tighten the nut to 52 N´m (38 ft. lbs.)
torque.
(24) Fill the pump reservoir with fluid.(25) Inspect the fuel supply line o-ring(s) and
replace if necessary. Connect fuel supply line to injec-
tior rail and verify connection by pulling outward on
the line.
(26) Install the fuel line bracket to the intake
manifold.
(27) Connect the coil rail electrical connectors and
oil pressure switch connector.
(28) Connect the following electrical connectors:
²Power steering pressure switch
²Coolant temperature sensor
²Six (6) fuel injector connectors
²Intake air temperature sensor
²Throttle position sensor
²Map sensor
²Crankshaft position sensor
²Oxygen sensor
²Camshaft position sensor
²Generator connector and B+ terminal wire
(29) Connect all previously removed vacuum hoses.
(30) Connect the body ground strap.
(31) Install the throttle, transmission line pres-
sure, and speed control cables to their mounting
bracket and connect them to the throttle body.
(32) Connect the heater hoses at the engine ther-
mostat housing and water pump.
(33) Install the fan assembly (Refer to 7 - COOL-
ING/ENGINE/RADIATOR FAN - INSTALLATION).
(34) Place the fan shroud in position over the fan.
(35) Install the radiator (Refer to 7 - COOLING/
ENGINE/RADIATOR - INSTALLATION).
(36) Connect the service valves to the A/C com-
pressor ports, if equipped with A/C.
(37) Charge the air conditioner system (Refer to 24
- HEATING & AIR CONDITIONING/PLUMBING -
STANDARD PROCEDURE).
(38) Connect the radiator hoses and automatic
transmission fluid cooler pipes, if equipped.
(39) Install the fan shroud to the radiator or radi-
ator/condenser (if equipped with A/C).
(40) Install upper radiator support.
(41) Connect the upper radiator hose and tighten
the clamp.
(42) Connect the lower radiator hose and tighten
the clamp.
(43) Fill crankcase with engine oil. (Refer to
LUBRICATION & MAINTENANCE/FLUID CAPACI-
TIES - SPECIFICATIONS) for correct capacities.
(44) Fill the cooling system with reusable coolant
or new coolant (Refer to 7 - COOLING - STANDARD
PROCEDURE).
(45) Align the hood to the scribe marks. Install the
hood.
(46) Install the air cleaner assembly.
(47) Install the battery and connect the battery
cable.
WJENGINE - 4.0L 9 - 13
ENGINE - 4.0L (Continued)

(2) Drain the coolant (Refer to 7 - COOLING -
STANDARD PROCEDURE) and disconnect the hoses
at the engine thermostat housing and the water
pump inlet. DO NOT waste reusable coolant. If the
solution is clean and is being drained only to service
the engine or cooling system, drain the coolant into a
clean container for reuse.
(3) Remove the air cleaner assembly (Refer to 9 -
ENGINE/AIR INTAKE SYSTEM/AIR CLEANER
HOUSING - REMOVAL).
(4) Remove the cylinder head cover (Refer to 9 -
ENGINE/CYLINDER HEAD/CYLINDER HEAD
COVER(S) - REMOVAL).
(5) Remove the capscrews, bridge and pivot assem-
blies and rocker arms (Refer to 9 - ENGINE/CYLIN-
DER HEAD/ROCKER ARM / ADJUSTER ASSY -
REMOVAL).
(6) Remove the push rods.Retain the push rods,
bridges, pivots and rocker arms in the same
order as removed.
(7) Remove the accessory drive belt (Refer to 7 -
COOLING/ACCESSORY DRIVE/DRIVE BELTS -
REMOVAL).
(8) Remove the A/C compressor mounting bolts
and secure the compressor to the side.
(9) Remove the power steering pump and bracket
from the intake manifold and water pump. Set the
pump and bracket aside. DO NOT disconnect the
hoses.
(10) Perform the Fuel System Pressure Release
procedure. (Refer to 14 - FUEL SYSTEM/FUEL
DELIVERY - STANDARD PROCEDURE).
(11) Disconnect the fuel supply line at the fuel rail.(12) Remove the intake and exhaust manifolds
from the engine cylinder head (Refer to 9 - ENGINE/
MANIFOLDS/INTAKE MANIFOLD - REMOVAL).
(13) Remove the coil rail (Refer to 8 - ELECTRI-
CAL/IGNITION CONTROL/COIL RAIL - REMOV-
AL).
(14) Remove spark plugs (Refer to 8 - ELECTRI-
CAL/IGNITION CONTROL/SPARK PLUG - REMOV-
AL).
(15) Disconnect the temperature sending unit wire
connector.
(16) Remove the engine cylinder head bolts. Bolt
No.14 cannot be removed until the head is moved for-
ward (Fig. 9). Pull bolt No.14 out as far as it will go
and then suspend the bolt in this position (tape
around the bolt).
(17) Remove the engine cylinder head and gasket
(Fig. 9).
(18) If this was the first time the bolts were
removed, put a paint dab on the top of the bolt. If the
bolts have a paint dab on the top of the bolt or it
isn't known if they were used before, discard the
bolts.
(19) Stuff clean lint free shop towels into the cyl-
inder bores.
NOTE: If the valves, springs, or seals are to be
inspected/replaced at this time, (Refer to 9 -
ENGINE/CYLINDER HEAD/INTAKE/EXHAUST
VALVES & SEATS - STANDARD PROCEDURE) for
proper inspection procedures.
Fig. 8 Cylinder Head 4.0L Engine
1 - CYLINDER HEAD BOLTS
2 - CYLINDER HEAD GASKET
3 - CYLINDER HEAD
Fig. 9 Engine Cylinder
1 - CYLINDER HEAD BOLTS
2 - CYLINDER HEAD GASKET
3 - CYLINDER HEAD
9 - 20 ENGINE - 4.0LWJ
CYLINDER HEAD (Continued)

(12) Install the push rods, rocker arms, pivots and
bridges in the order they were removed (Refer to 9 -
ENGINE/CYLINDER HEAD/ROCKER ARM /
ADJUSTER ASSY - INSTALLATION).
(13) Install the engine cylinder head cover (Refer
to 9 - ENGINE/CYLINDER HEAD/CYLINDER
HEAD COVER(S) - INSTALLATION).
(14) Attach the air conditioner compressor mount-
ing bracket to the engine cylinder head and block.
Tighten the bolts to 40 N´m (30 ft. lbs.) torque.
(15) Attach the air conditioning compressor to the
bracket. Tighten the bolts to 27 N´m (20 ft. lbs.)
torque.
CAUTION: The serpentine drive belt must be routed
correctly. Incorrect routing can cause the water
pump to turn in the opposite direction causing the
engine to overheat.
(16) Install the serpentine drive belt. (Refer to 7 -
COOLING/ACCESSORY DRIVE/DRIVE BELTS -
INSTALLATION).
(17) Install the air cleaner and ducting.
(18) Connect the hoses to the engine thermostat
housing and fill the cooling system to the specified
level (Refer to 7 - COOLING - STANDARD PROCE-
DURE).
(19) The automatic transmission throttle linkage
and cable must be adjusted after completing the
engine cylinder head installation (Refer to 21 -
TRANSMISSION/TRANSAXLE/AUTOMATIC - AW4/
THROTTLE VALVE CABLE - ADJUSTMENTS).
(20) Install the temperature sending unit and con-
nect the wire connector.
(21) If equipped with air conditioning, install A/C
compressor (Refer to 24 - HEATING & AIR CONDI-
TIONING/PLUMBING/A/C COMPRESSOR -
INSTALLATION) and charge A/C system (Refer to 24
- HEATING & AIR CONDITIONING/PLUMBING -
STANDARD PROCEDURE).
(22) Connect negative cable to battery.
WARNING: USE EXTREME CAUTION WHEN THE
ENGINE IS OPERATING. DO NOT STAND IN DIRECT
LINE WITH THE FAN. DO NOT PUT HANDS NEAR
THE PULLEYS, BELTS OR FAN. DO NOT WEAR
LOOSE CLOTHING.
(23) Operate the engine with the radiator cap off.
Inspect for leaks and continue operating the engine
until the engine thermostat opens. Add coolant, if
required.CYLINDER HEAD COVER(S)
DESCRIPTION
The cylinder head cover (Fig. 11) is made of
stamped steel and incorporates the Crankcase Venti-
lation (CCV) Hoses and the oil fill opening.
REMOVAL
The cylinder head cover is isolated from the cylin-
der head via grommets and a reusable molded rubber
gasket. The grommet and limiter are retained in the
cylinder head cover.
(1) Disconnect negative cable from battery.
(2) Disconnect the Crankcase Ventilation (CCV)
vacuum hose from engine cylinder head cover.
(3) Disconnect the fresh air inlet hose from the
engine cylinder head cover.
(4) Disconnect the accelerator, transmission, and
speed (if equipped) control cables from the throttle
body (Fig. 12).
(5) Remove the three bolts that fasten the control
cable bracket to the intake manifold.
(6) Remove control cables from cylinder head cover
clip.
(7) Position control cables and bracket away from
cylinder head cover secure with tie straps.
(8) Remove the engine cylinder head cover mount-
ing bolts.
(9) Remove the engine cylinder head cover and
gasket.
Fig. 11 Cylinder Head Cover
9 - 22 ENGINE - 4.0LWJ
CYLINDER HEAD (Continued)

INSTALLATION
A gear-type oil pump is mounted at the underside
of the cylinder block opposite the No.4 main bearing.
(1) Install the oil pump on the cylinder block using
a replacement gasket. Tighten the bolts to 23 N´m
(17 ft. lbs.) torque.
(2) Install the oil pan (Refer to 9 - ENGINE/LU-
BRICATION/OIL PAN - INSTALLATION).
(3) Fill the oil pan with oil to the specified level.
INTAKE MANIFOLD
DESCRIPTION
The intake manifold (Fig. 83) is made of cast alu-
minum and uses eleven bolts to mount to the cylin-
der head. This mounting style improves sealing and
reduces the chance of leaks.
DIAGNOSIS AND TESTING - INTAKE
MANIFOLD LEAKAGE
An intake manifold air leak is characterized by
lower than normal manifold vacuum. Also, one or
more cylinders may not be functioning.
WARNING: USE EXTREME CAUTION WHEN THE
ENGINE IS OPERATING. DO NOT STAND IN A
DIRECT LINE WITH THE FAN. DO NOT PUT YOUR
HANDS NEAR THE PULLEYS, BELTS OR THE FAN.
DO NOT WEAR LOOSE CLOTHING.
(1) Start the engine.
(2) Spray a small stream of water at the suspected
leak area.
(3) If a change in RPM is observed the area of the
suspected leak has been found.
(4) Repair as required.
REMOVAL
NOTE: THE ENGINE INTAKE AND EXHAUST MANI-
FOLD MUST BE REMOVED AND INSTALLED
TOGETHER. THE MANIFOLDS USE A COMMON
GASKET AT THE CYLINDER HEAD.
(1) Disconnect the battery negative cable.
(2) Remove air cleaner inlet hose from the resona-
tor assembly.
(3) Remove the air cleaner assembly.
(4) Remove the throttle cable, vehicle speed control
cable (if equipped) and the transmission line pres-
sure cable (Refer to 21 - TRANSMISSION/TRANS-
AXLE/AUTOMATIC - AW4/THROTTLE VALVE
CABLE - REMOVAL).
(5) Disconnect the following electrical connections
and secure their harness out of the way:
²Throttle Position Sensor
²Idle Air Control Motor
²Coolant Temperature Sensor (at thermostat
housing)
²Intake Air Temperature Sensor
²Oxygen Sensor
²Crank Position Sensor
²Six (6) Fuel Injector Connectors
²Manifold Absolute Pressure (MAP) Sensor.
(6) Disconnect HVAC, and Brake Booster vacuum
supply hoses at the intake manifold.
(7) Perform the fuel pressure release procedure.
(Refer to 14 - FUEL SYSTEM/FUEL DELIVERY -
STANDARD PROCEDURE).
(8) Disconnect and remove the fuel system supply
line from the fuel rail assembly.
(9) Remove the accessory drive belt (Refer to 7 -
COOLING/ACCESSORY DRIVE/DRIVE BELTS -
REMOVAL).
(10) Remove the power steering pump from the
intake manifold and set aside.
(11) Raise the vehicle.
(12) Disconnect the exhaust pipes from the engine
exhaust manifolds.
(13) Lower the vehicle.
(14) Remove the intake manifold and exhaust
manifold bolts and manifolds (Fig. 84).
INSTALLATION
If the manifold is being replaced, ensure all the fit-
ting, etc. are transferred to the replacement mani-
fold.
(1) Install a new engine exhaust/intake manifold
gasket over the alignment dowels on the cylinder
head.
(2) Position the engine exhaust manifolds to the
cylinder head. Install fastener Number 3 and finger
tighten at this time (Fig. 84).
Fig. 83 Intake Manifold 4.0L Engine
WJENGINE - 4.0L 9 - 57
OIL PUMP (Continued)

DIAGNOSIS AND TESTING - CYLINDER
COMBUSTION PRESSURE LEAKAGE
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.
(1) Check the coolant level and fill as required. DO
NOT install the radiator cap.
(2) Start and operate the engine until it attains
normal operating temperature, then turn the engine
OFF.
(3) Remove the spark plugs.
(4) Remove the oil filler cap.
(5) Remove the air cleaner.(6) Calibrate the tester according to the manufac-
turer'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.
(7) Perform the test procedures on each cylinder
according to the tester manufacturer's instructions.
Set piston of cylinder to be tested at TDC compres-
sion,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 CYLINDER COMBUSTION PRESSURE
LEAKAGE DIAGNOSIS CHART .
CYLINDER COMBUSTION PRESSURE LEAKAGE DIAGNOSIS CHART
CONDITION POSSIBLE CAUSE CORRECTION
AIR ESCAPES THROUGH
THROTTLE BODYIntake valve bent, burnt, or not
seated properlyInspect valve and valve seat.
Reface or replace, as necessary.
Inspect valve springs. Replace as
necessary.
AIR ESCAPES THROUGH
TAILPIPEExhaust valve bent, burnt, or not
seated properlyInspect valve and valve seat.
Reface or replace, as necessary.
Inspect valve springs. Replace as
necessary.
AIR ESCAPES THROUGH
RADIATORHead gasket leaking or cracked
cylinder head or blockRemove cylinder head and inspect.
Replace defective part
MORE THAN 50% LEAKAGE
FROM ADJACENT CYLINDERSHead gasket leaking or crack in
cylinder head or block between
adjacent cylindersRemove cylinder head and inspect.
Replace gasket, head, or block as
necessary
MORE THAN 25% LEAKAGE AND
AIR ESCAPES THROUGH OIL
FILLER CAP OPENING ONLYStuck or broken piston rings;
cracked piston; worn rings and/or
cylinder wallInspect for broken rings or piston.
Measure ring gap and cylinder
diameter, taper and out-of-round.
Replace defective part as necessary
WJENGINE - 4.7L 9 - 69
ENGINE - 4.7L (Continued)