2002 JEEP GRAND CHEROKEE sensor

(32) Disconnect body ground strap at the right side
cowl.
NOTE: It will be necessary to support the transmis-
sion in order to remove the engine.
(33) Position a suitable jack under the transmis-
sion.
(34) Remove the engine mount through bolts.
(35) Raise engine slightly, then remove both left
and right side engine mounts from engine. (Refer to
9 - ENGINE/ENGINE MOUNTING/FRONT MOUNT
- REMOVAL).
(36) Remove engine from the vehicle.
INSTALLATION
(1) Position engine in the vehicle.
(2) Install both left and right side engine mounts
onto engine (Refer to 9 - ENGINE/ENGINE MOUNT-
ING/FRONT MOUNT - INSTALLATION).
(3) Install transmission to engine mounting bolts.
Tighten the bolts to 41 N´m (30 ft. lbs.).(4) Remove jack from under the transmission.
(5) Remove engine lifting fixture special tool 8347
(Fig. 7).
(6) Connect ground straps on the left side of the
engine.
(7) Install power steering pump (Refer to 19 -
STEERING/PUMP - INSTALLATION).
(8) Connect fuel supply line quick connect fitting
(Refer to 14 - FUEL SYSTEM/FUEL DELIVERY/
QUICK CONNECT FITTING - STANDARD PROCE-
DURE).
(9) Connect engine harness at the following points
(Fig. 6):
²Intake Air Temperature (IAT) Sensor
²Idle Air Control (IAC) Motor
²Fuel Injectors
²Throttle Position (TPS) Switch
²Engine Oil Pressure Switch
²Engine Coolant Temperature (ECT) Sensor
²Manifold Absolute Pressure (MAP) Sensor
Fig. 6 Throttle Body Connection Points
1 - THROTTLE BODY
2 - TPS
3 - IAC MOTOR
4 - IAT SENSOR (THREADED TYPE)
5 - MOUNTING SCREWS
Fig. 7 Engine Lifting Fixture Attachment Locations
1 - ATTACHING LOCATION
2 - ADJUSTABLE HOOK
3 - SPECIAL TOOL 8347 ENGINE LIFT FIXTURE
4 - ATTACHING LOCATIONS
WJENGINE - 4.7L 9 - 73
ENGINE - 4.7L (Continued)

²Camshaft Position (CMP) Sensor
²Coil Over Plugs
(10) Install generator (Refer to 8 - ELECTRICAL/
CHARGING/GENERATOR - INSTALLATION).
(11) Install radiator (Refer to 7 - COOLING/EN-
GINE/RADIATOR - INSTALLATION).
(12) Install A/C condenser (Refer to 24 - HEATING
& AIR CONDITIONING/PLUMBING/A/C CON-
DENSER - INSTALLATION).
(13) Connect radiator lower hose at the thermostat
housing.
(14) Connect the transmission oil cooler lines to
the radiator.
(15) Install A/C compressor. (Refer to 24 - HEAT-
ING & AIR CONDITIONING/PLUMBING/A/C COM-
PRESSOR - INSTALLATION).
(16) Install accessory drive belt (Refer to 7 -
COOLING/ACCESSORY DRIVE/DRIVE BELTS -
INSTALLATION) and radiator fan (Refer to 7 -
COOLING/ENGINE/RADIATOR FAN - INSTALLA-
TION).
(17) Install breathers, then connect tube to both
crankcase breathers (Fig. 5).
(18) Connect throttle and speed control cables.
(19) Install throttle body resonator assembly and
inlet hose.
(20) Raise vehicle.
(21) Connect two ground straps on the lower left
hand side of the engine and one ground strap on the
lower right side.
(22) Install torque converter bolts.
(23) Connect crankshaft position sensor (Fig. 4).
(24) Install starter.
(25) Install rubber splash shield.
CAUTION: The structural cover requires a specific
torque sequence. Failure to follow this sequence
may cause severe damage to the cover.
(26) Install structural cover (Refer to 9 - ENGINE/
ENGINE BLOCK/STRUCTURAL COVER - INSTAL-
LATION).
(27) Install exhaust crossover pipe.
(28) Install engine block heater power cable, If
equipped.
(29) Lower vehicle.
(30) Check and fill engine oil (Refer to LUBRICA-
TION & MAINTENANCE/FLUID TYPES - SPECIFI-
CATIONS).
(31) Recharge the A/C system (Refer to 24 - HEAT-
ING & AIR CONDITIONING/PLUMBING - STAN-
DARD PROCEDURE).
(32) Refill the engine cooling system (Refer to 7 -
COOLING - STANDARD PROCEDURE).
(33) Connect the battery negative cable.
(34) Start engine and check for leaks.SPECIFICATIONS
4.7L ENGINE
DESCRIPTION SPECIFICATION
GENERAL SPECIFICATIONS
Engine Type 90É SOHC V-8 16-Valve
Displacement 4.7 Liters / 4701cc
(287 Cubic Inches)
Bore 93.0 mm (3.66 in.)
Stroke 86.5 mm (3.40 in.)
Compression Ratio 9.0:1
Horsepower 235 BHP @ 4800 RPM
Torque 295 LB-FT @ 3200 RPM
Lead Cylinder #1 Left Bank
Firing Order 1-8-4-3-6-5-7-2
CYLINDER BLOCK
Cylinder Block Cast Iron
Bore Diameter 93.010   .0075 mm
(3.6619   0.0003 in.)
Out of Round (MAX) 0.076 mm (0.003 in.)
Taper (MAX) 0.051 mm (0.002 in.)
PISTONS
Material Aluminum Alloy
Diameter 92.975 mm (3.6605 in.)
Weight 367.5 grams (12.96 oz)
Ring Groove Diameter
No. 1 83.73 - 83.97 mm
(3.296 - 3.269 in.)
No. 2 82.833 - 83.033 mm
(3.261 - 3.310 in.)
No. 3 83.88 - 84.08 mm
(3.302 - 3.310 in.)
PISTON PINS
Type Pressed Fit
Clearance In Piston 0.010 - 0.019 mm
(0.0004 - 0.0008 in.)
Diameter 24.013 - 24.016 mm
(0.9454 - 0.9456 in.)
9 - 74 ENGINE - 4.7LWJ
ENGINE - 4.7L (Continued)

(5) Position Special Tool 8350 timing chain wedge
between the timing chain strands. Tap the tool to
securely wedge the timing chain against the ten-
sioner arm and guide (Fig. 31).
(6) Remove the camshaft position sensor (Fig. 32).
NOTE: When gripping the camshaft, place the pliers
on the tube portion of the camshaft only. Do not
grip the lobes or the sprocket areas.
(7) Hold the camshaft with adjustable pliers while
removing the camshaft sprocket bolt and sprocket
(Fig. 33).
(8) Using the pliers, gently allow the camshaft to
rotate 45É counter-clockwise until the camshaft is in
the neutral position (no valve load).
(9) Starting at the outside working inward, loosen
the camshaft bearing cap retaining bolts 1/2 turn at
a time. Repeat until all load is off the bearing caps.
CAUTION: DO NOT STAMP OR STRIKE THE CAM-
SHAFT BEARING CAPS. SEVERE DAMAGE WILL
OCCUR TO THE BEARING CAPS.
NOTE: When the camshaft is removed the rocker
arms may slide downward, mark the rocker arms
before removing camshaft.
(10) Remove the camshaft bearing caps and the
camshaft.
Fig. 31 Securing Timing Chain Tensioners Using Timing Chain Wedge
1 - LEFT CYLINDER HEAD
2 - RIGHT CYLINDER HEAD3 - SPECIAL TOOL 8350 WEDGE
4 - SPECIAL TOOL 8350 WEDGE
Fig. 32 Camshaft Position Sensor
1 - CRANKSHAFT POSITION SENSOR
2 - CYLINDER HEAD COVER
3 - CAMSHAFT POSITION SENSOR
4 - RIGHT SIDE CYLINDER BLOCK
WJENGINE - 4.7L 9 - 101
CAMSHAFT(S) - RIGHT (Continued)

INSTALLATION
(1) Lubricate camshaft journals with clean engine
oil.
NOTE: Position the right side camshaft so that the
camshaft sprocket dowel is near the 10 o'clock
position, This will place the camshaft at the neutral
position easing the installation of the camshaft
bearing caps.
(2) Position the camshaft into the cylinder head.
(3) Install the camshaft bearing caps, hand tighten
the retaining bolts.
(4) Working in 1/2 turn increments, tighten the
bearing cap retaining bolts starting with the middle
cap working outward (Fig. 34).
(5) Torque the camshaft bearing cap retaining
bolts to 11 N´m (100 in. lbs.).
(6) Position the camshaft drive gear into the tim-
ing chain aligning the V8 mark between the two
marked chain links (Two links marked during
removal) (Fig. 35).NOTE: When gripping the camshaft, place the pliers
on the tube portion of the camshaft only. Do not
grip the lobes or the sprocket areas.
(7) Using the adjustable pliers, rotate the cam-
shaft until the camshaft sprocket dowel is aligned
with the slot in the camshaft sprocket. Install the
sprocket onto the camshaft (Fig. 36).
CAUTION: Remove excess oil from camshaft
sprocket bolt. Failure to do so can cause bolt over-
torque resulting in bolt failure.
(8) Remove excess oil from camshaft sprocket bolt,
then install the camshaft sprocket retaining bolt and
hand tighten.
(9) Remove timing chain wedge special tool 8350
(Fig. 31).
(10) Using Special Tool 6958 spanner wrench with
adapter pins 8346 (Fig. 37), torque the camshaft
sprocket retaining bolt to 122 N´m (90 ft. lbs.).
(11) Install the camshaft position sensor (Fig. 32).
(12) Install the cylinder head cover (Refer to 9 -
ENGINE/CYLINDER HEAD/CYLINDER HEAD
COVER(S) - INSTALLATION).
Fig. 33 Camshaft Sprocket and Chain
1 - ADJUSTABLE PLIERS
2 - SPROCKET BOLT
3 - CAMSHAFT SPROCKET AND CHAIN
4 - CAMSHAFTFig. 34 Camshaft Bearing Caps Tightening
Sequence
9 - 102 ENGINE - 4.7LWJ
CAMSHAFT(S) - RIGHT (Continued)

Bearing
MarkSIZE USED WITH
JOURNAL SIZE
.025 US.025 mm 50.983-50.967 mm
(.001 in.) (2.0073-2.0066 in.)
Std.STANDARD 50.992-51.008 mm
(2.0076-2.0082 in.)
.250 US.250 mm 50.758-50.742 mm
(.010 in.) (1.9984-1.9978 in.)
(9) Repeat the Plastigage measurement to verify
your bearing selection prior to final assembly.
(10) Once you have selected the proper insert,
install the insert and cap. Tighten the connecting rod
bolts to 27 N´m (20 ft. lbs.) plus a 90É turn.
Slide snug-fitting feeler gauge between the con-
necting rod and crankshaft journal flange (Fig. 52).
Refer to Engine Specifications for the proper clear-
ance. Replace the connecting rod if the side clearance
is not within specification.
CRANKSHAFT
DESCRIPTION
The 4.7L crankshaft is constructed of nodular cast
iron. The crankshaft for the 4.7L H.O. is constructed
offorged steel.The crankshaft is a cross shaped
four throw design with eight counterweights for bal-
ancing purposes. The crankshaft is supported by five
select fit main bearings with the number three serv-
ing as the thrust washer location. The main journalsof the crankshaft are cross drilled to improve rod
bearing lubrication. The number eight counterweight
has provisions for crankshaft position sensor target
wheel mounting. The select fit main bearing mark-
ings are located on the rear side of the target wheel.
The crankshaft oil seals are one piece design. The
front oil seal is retained in the timing chain cover,
and the rear seal is pressed in to a bore formed by
the cylinder block and the bedplate assembly.
STANDARD PROCEDURE - MEASURING
CRANKSHAFT END PLAY
(1) Mount a dial indicator to front of engine with
the locating probe on nose of crankshaft (Fig. 53).
(2) Move crankshaft all the way to the rear of its
travel.
(3) Zero the dial indicator.
(4) Move crankshaft all the way to the front and
read the dial indicator. (Refer to 9 - ENGINE -
SPECIFICATIONS) for end play specification.
Fig. 51 Measuring Bearing Clearance with
Plastigage
1 - PLASTIGAGE SCALE
2 - COMPRESSED PLASTIGAGE
Fig. 52 Checking Connecting Rod Side Clearance -
Typical
Fig. 53 Checking Crankshaft End PlayÐTypical
WJENGINE - 4.7L 9 - 111
CONNECTING ROD BEARINGS (Continued)

CRANKSHAFT MAIN BEARING SELECTION
The main bearings are ªselect fitº to achieve proper
oil clearances. For main bearing selection, the crank-
shaft position sensor target wheel has grade identifi-
cation marks stamped into it (Fig. 60). These marks
are read from left to right, corresponding with jour-
nal number 1, 2, 3, 4 and 5. The crankshaft position
sensor target wheel is mounted to the number 8
counter weight on the crankshaft.
NOTE: Service main bearings are coded. These
codes identify what size (grade) the bearing is.
MAIN BEARING SELECTION CHARTÐ4.7L
GRADE SIZE mm
(in.)FOR USE WITH
MARKING JOURNAL SIZE
A0.008 mm
U/S63.488±63.496 mm
(0.0004 in.)
U/S(2.4996±2.4999 in.)
BNOMINAL 63.496±63.504 mm
(2.4999±2.5002 in.)
C0.008 mm
O/S63.504±63.512 mm
(0.0004 in.)
O/S(2.5002±2.5005 in.)
INSPECTION
Wipe the inserts clean and inspect for abnormal
wear patterns and for metal or other foreign material
imbedded in the lining. Normal main bearing insert
wear patterns are illustrated (Fig. 61).
NOTE: If any of the crankshaft journals are scored,
the crankshaft must be repaired or replaced.
Inspect the back of the inserts for fractures, scrap-
ings or irregular wear patterns.
Inspect the upper insert locking tabs for damage.
Replace all damaged or worn bearing inserts.
CRANKSHAFT OIL SEAL -
FRONT
REMOVAL
(1) Disconnect negative cable from battery.
(2) Remove accessory drive belt (Refer to 7 -
COOLING/ACCESSORY DRIVE/DRIVE BELTS -
REMOVAL).
(3) Remove A/C compressor mouning fasteners and
set aside.
(4) Drain cooling system (Refer to 7 - COOLING -
STANDARD PROCEDURE).
(5) Remove upper radiator hose.
(6) Disconnect electrical connector for fan mounted
inside radiator shroud.
(7) Remove radiator shroud attaching fasteners.
NOTE: Transmission cooler line snaps into shroud
lower right hand corner.
Fig. 60 Main Bearing Markings on Target Wheel
1 - REARMOST CRANKSHAFT COUNTER WEIGHT
2 - TARGET WHEEL
3 - MAIN BEARING SELECT FIT MARKINGS
Fig. 61 Main Bearing Wear Patterns
1 - UPPER INSERT
2 - NO WEAR IN THIS AREA
3 - LOW AREA IN BEARING LINING
4 - LOWER INSERT
WJENGINE - 4.7L 9 - 115
CRANKSHAFT MAIN BEARINGS (Continued)

Fig. 88 Engine Oil Lubrication System
1 - LEFT CYLINDER HEAD OIL GALLERY
2 - OIL PRESSURE SENSOR LOCATION
3 - TO LEFT CYLINDER HEAD
4 - OIL FEED TO IDLER SHAFT
5 - OIL PUMP OUTLET TO BLOCK
6 - OIL PUMP7 - TO CRANKSHAFT MAIN JOURNALS
8 - RIGHT CYLINDER HEAD OIL GALLERY
9 - TO RIGHT CYLINDER HEAD
10 - CYLINDER BLOCK MAIN GALLERY
11 - OIL FEED TO BOTH SECONDARY TENSIONERS
WJENGINE - 4.7L 9 - 127
LUBRICATION (Continued)

(5) If the leak is not detected, very slowly turn the
crankshaft and watch for leakage. If a leak is
detected between the crankshaft and seal while
slowly turning the crankshaft, it is possible the
crankshaft seal surface is damaged. The seal area on
the crankshaft could have minor nicks or scratches
that can be polished out with emery cloth.
CAUTION: Use extreme caution when crankshaft
polishing is necessary to remove minor nicks or
scratches. The crankshaft seal flange is specially
machined to complement the function of the rear oil
seal.
(6) For bubbles that remain steady with shaft
rotation, no further inspection can be done until dis-
assembled. (Refer to 9 - ENGINE - DIAGNOSIS AND
TESTING), under the Oil Leak row, for components
inspections on possible causes and corrections.
(7) After the oil leak root cause and appropriate
corrective action have been identified, (Refer to 9 -
ENGINE/ENGINE BLOCK/CRANKSHAFT OIL
SEAL - REAR - REMOVAL).
DIAGNOSIS AND TESTINGÐENGINE OIL LEAK
Begin with a thorough visual inspection of the
engine, particularly at the area of the suspected leak.If an oil leak source is not readily identifiable, the
following 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
approximately 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,
repair per service manual instructions.
(4) If dye is not observed, drive the vehicle at var-
ious speeds for approximately 24km (15 miles), and
repeat inspection.If the oil leak source is not pos-
itively identified at this time, proceed with the air
leak detection test method.
Air Leak Detection Test Method
(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
detected and identified, repair per service manual
procedures.
(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.
Install the PCV valve and breather cap hose.
(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
engine, a more involved inspection is necessary. The
following steps should be followed to help pinpoint
the source of the leak.
Fig. 89 Oil Pressure Sending Unit
1 - BELT
2 - OIL PRESSURE SENSOR
3 - OIL FILTER
4 - ELEC. CONNECTOR
WJENGINE - 4.7L 9 - 129
LUBRICATION (Continued)