2002 JEEP LIBERTY exhaust

DESCRIPTION-3.7L
The Camshaft Position Sensor (CMP) on the 3.7L
6±cylinder engine is bolted to the right-front side of
the right cylinder head (Fig. 6).
OPERATION
OPERATION - 2.4L
The Camshaft Position Sensor (CMP) sensor con-
tains a hall effect device referred to as a sync signal
generator. A rotating target wheel (tonewheel) for the
CMP is located behind the exhaust valve-camshaft
drive gear (Fig. 7). The target wheel is equipped with
a cutout (notch) around 180 degrees of the wheel.
The CMP detects this cutout every 180 degrees of
camshaft gear rotation. Its signal is used in conjunc-
tion with the Crankshaft Position Sensor (CKP) to
differentiate between fuel injection and spark events.
It is also used to synchronize the fuel injectors with
their respective cylinders.
When the leading edge of the target wheel cutout
enters the tip of the CMP, the interruption of mag-
netic field causes the voltage to switch high, result-
ing in a sync signal of approximately 5 volts.
When the trailing edge of the target wheel cutout
leaves the tip of the CMP, the change of the magnetic
field causes the sync signal voltage to switch low to 0
volts.
OPERATION - 3.7L
The Camshaft Position Sensor (CMP) sensor con-
tains a hall effect device referred to as a sync signal
generator. A rotating target wheel (tonewheel) for the
CMP is located at the front of the camshaft for the
right cylinder head (Fig. 8). This sync signal genera-
tor detects notches located on a tonewheel. As the
tonewheel rotates, the notches pass through the sync
signal generator. The signal from the CMP sensor is
used in conjunction with the Crankshaft Position
Sensor (CKP) to differentiate between fuel injection
and spark events. It is also used to synchronize the
fuel injectors with their respective cylinders.
When the leading edge of the tonewheel notch
enters the tip of the CMP, the interruption of mag-
netic field causes the voltage to switch high, result-
ing in a sync signal of approximately 5 volts.
When the trailing edge of the tonewheel notch
leaves then tip of the CMP, the change of the mag-
netic field causes the sync signal voltage to switch
low to 0 volts.
Fig. 6 CAMSHAFT POSITION SENSOR - 3.7L
1 - RIGHT/FRONT OF RIGHT CYLINDER HEAD
2 - CMP MOUNTING BOLT
3 - CMP LOCATION
Fig. 7 CMP FACE AT TARGET WHEEL-2.4L
1 - CAMSHAFT DRIVE GEAR
2 - TARGETWHEEL (TONEWHEEL)
3 - FACE OF CMP SENSOR
4 - CUTOUT (NOTCH)
8I - 6 IGNITION CONTROLKJ
CAMSHAFT POSITION SENSOR (Continued)

3.7L
The Camshaft Position Sensor (CMP) on the 3.7L
V-6 engine is bolted to the front/top of the right cyl-
inder head.
(1) Clean out machined hole in cylinder head.
(2) Apply a small amount of engine oil to sensor
o-ring.
(3) Install sensor into cylinder head with a slight
rocking and twisting action.
CAUTION: Before tightening sensor mounting bolt,
be sure sensor is completely flush to cylinder head.
If sensor is not flush, damage to sensor mounting
tang may result.
(4) Install mounting bolt and tighten. Refer to
torque specifications.
(5) Connect electrical connector to sensor.
IGNITION COIL
DESCRIPTION
2.4L
The coil assembly consists of 2 different coils
molded together. The assembly is mounted to the top
of the engine (Fig. 14).
3.7L
The 3.7L V-6 engine uses 6 dedicated, and individ-
ually fired coil for each spark plug (Fig. 15). Each
coil is mounted directly into the cylinder head and
onto the top of each spark plug (Fig. 16).
OPERATION
2.4L
The coil fires two spark plugs simultaneously. One
plug is under compression, the other plug fires on the
exhaust stroke (lost spark). Coil number one fires
Fig. 14 IGNITION COIL - 2.4L
1 - IGNITION COIL
2 - MOUNTING BOLTS (4)
Fig. 15 IGNITION COIL - 3.7L
1 - O-RING
2 - IGNITION COIL
3 - ELECTRICAL CONNECTOR
Fig. 16 IGNITION COIL LOCATION - 3.7L
1 - IGNITION COIL
2 - COIL MOUNTING NUT
KJIGNITION CONTROL 8I - 9
CAMSHAFT POSITION SENSOR (Continued)

WARNING: BE SURE THAT THE IGNITION SWITCH
ALWAYS IS IN THE OFF POSITION, UNLESS THE
PROCEDURE REQUIRES IT TO BE ON.
WARNING: SET THE PARKING BRAKE WHEN
WORKING ON ANY VEHICLE. AN AUTOMATIC
TRANSMISSION SHOULD BE IN PARK. A MANUAL
TRANSMISSION SHOULD BE IN NEUTRAL.
WARNING: OPERATE THE ENGINE ONLY IN A
WELL-VENTILATED AREA.
WARNING: KEEP AWAY FROM MOVING PARTS
WHEN THE ENGINE IS RUNNING, ESPECIALLY THE
FAN AND BELTS.
WARNING: TO PREVENT SERIOUS BURNS, AVOID
CONTACT WITH HOT PARTS SUCH AS THE RADIA-
TOR, EXHAUST MANIFOLD(S), TAIL PIPE, CATA-
LYTIC CONVERTER AND MUFFLER.
WARNING: DO NOT ALLOW FLAME OR SPARKS
NEAR THE BATTERY. GASES ARE ALWAYS
PRESENT IN AND AROUND THE BATTERY.
WARNING: ALWAYS REMOVE RINGS, WATCHES,
LOOSE HANGING JEWELRY AND AVOID LOOSE
CLOTHING.
DIAGNOSIS AND TESTING - WIRING HARNESS
TROUBLESHOOTING TOOLS
When diagnosing a problem in an electrical circuit
there are several common tools necessary. These tools
are listed and explained below.
²Jumper Wire - This is a test wire used to con-
nect two points of a circuit. It can be used to bypass
an open in a circuit.
WARNING: NEVER USE A JUMPER WIRE ACROSS
A LOAD, SUCH AS A MOTOR, CONNECTED
BETWEEN A BATTERY FEED AND GROUND.
²Voltmeter - Used to check for voltage on a cir-
cuit. Always connect the black lead to a known good
ground and the red lead to the positive side of the
circuit.
CAUTION: Most of the electrical components used
in today's vehicles are Solid State. When checking
voltages in these circuits, use a meter with a 10 -
megohm or greater impedance rating.²Ohmmeter - Used to check the resistance
between two points of a circuit. Low or no resistance
in a circuit means good continuity.
CAUTION: Most of the electrical components used
in today's vehicles are Solid State. When checking
resistance in these circuits use a meter with a 10 -
megohm or greater impedance rating. In addition,
make sure the power is disconnected from the cir-
cuit. Circuits that are powered up by the vehicle's
electrical system can cause damage to the equip-
ment and provide false readings.
²Probing Tools - These tools are used for probing
terminals in connectors (Fig. 5). Select the proper
size tool from Special Tool Package 6807, and insert
it into the terminal being tested. Use the other end
of the tool to insert the meter probe.
INTERMITTENT AND POOR CONNECTIONS
Most intermittent electrical problems are caused
by faulty electrical connections or wiring. It is also
possible for a sticking component or relay to cause a
problem. Before condemning a component or wiring
assembly, check the following items.
²Connectors are fully seated
²Spread terminals, or terminal push out
²Terminals in the wiring assembly are fully
seated into the connector/component and locked into
position
²Dirt or corrosion on the terminals. Any amount
of corrosion or dirt could cause an intermittent prob-
lem
²Damaged connector/component casing exposing
the item to dirt or moisture
²Wire insulation that has rubbed through causing
a short to ground
²Some or all of the wiring strands broken inside
of the insulation
²Wiring broken inside of the insulation
Fig. 5 PROBING TOOL
1 - SPECIAL TOOL 6801
2 - PROBING END
KJ8W-01 WIRING DIAGRAM INFORMATION8Wa-01-7
WIRING DIAGRAM INFORMATION (Continued)

ENGINE - 3.7L
TABLE OF CONTENTS
page page
ENGINE - 3.7L
DESCRIPTION..........................3
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - ENGINE
DIAGNOSIS - INTRODUCTION............4
DIAGNOSIS AND TESTING - ENGINE
DIAGNOSIS - PERFORMANCE............4
DIAGNOSIS AND TESTING - ENGINE
DIAGNOSIS - MECHANICAL..............6
DIAGNOSIS AND TESTING - ENGINE
DIAGNOSIS - LUBRICATION..............7
DIAGNOSIS AND TESTING - CYLINDER
COMPRESSION PRESSURE..............8
DIAGNOSIS AND TESTING - CYLINDER
COMBUSTION PRESSURE LEAKAGE.......8
STANDARD PROCEDURE
STANDARD PROCEDURE - ENGINE
GASKET SURFACE PREPARATION.........9
STANDARD PROCEDURE - REPAIR
DAMAGED OR WORN THREADS..........9
STANDARD PROCEDURE - ENGINE CORE
AND OIL GALLERY PLUGS..............10
REMOVAL.............................10
INSTALLATION.........................11
SPECIFICATIONS
TORQUE............................12
3.7L ENGINE.........................12
SPECIAL TOOLS
3.7L ENGINE.........................15
AIR CLEANER ELEMENT
REMOVAL - 3.7L........................19
INSTALLATION - 3.7L....................19
CYLINDER HEAD - LEFT
DESCRIPTION - VALVE GUIDES...........19
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - HYDRAULIC
LASH ADJUSTER.....................19
DIAGNOSIS AND TESTING - CYLINDER
HEAD GASKET.......................19
REMOVAL.............................20
CLEANING............................22
INSTALLATION.........................22
CAMSHAFT(S)
DESCRIPTION.........................23
REMOVAL.............................24
INSTALLATION.........................25
CYLINDER HEAD COVER(S)
DESCRIPTION.........................25
REMOVAL.............................25INSTALLATION.........................26
INTAKE/EXHAUST VALVES & SEATS
DESCRIPTION.........................26
STANDARD PROCEDURE - REFACING......26
REMOVAL.............................27
INSTALLATION.........................28
ROCKER ARM
DESCRIPTION.........................29
VALVE GUIDE SEALS
DESCRIPTION.........................29
VALVE SPRINGS
DESCRIPTION.........................29
REMOVAL.............................29
INSTALLATION.........................29
CYLINDER HEAD - RIGHT
DESCRIPTION
DESCRIPTION - CYLINDER HEAD........30
DESCRIPTION - VALVE GUIDES..........30
DESCRIPTION........................30
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - HYDRAULIC
LASH ADJUSTER.....................30
DIAGNOSIS AND TESTING - CYLINDER
HEAD GASKET.......................30
REMOVAL.............................31
CLEANING............................31
INSPECTION..........................32
INSTALLATION.........................32
CAMSHAFT(S)
DESCRIPTION.........................33
REMOVAL.............................33
INSTALLATION.........................33
CYLINDER HEAD COVER(S)
REMOVAL.............................34
INSTALLATION.........................34
INTAKE/EXHAUST VALVES & SEATS
STANDARD PROCEDURE - REFACING......34
REMOVAL.............................35
INSTALLATION.........................36
ROCKER ARM
DESCRIPTION.........................37
REMOVAL.............................37
INSTALLATION.........................37
VALVE GUIDE SEALS
DESCRIPTION.........................38
VALVE SPRINGS
DESCRIPTION.........................38
REMOVAL.............................38
INSTALLATION.........................38
KJENGINE - 3.7L 9 - 1

ENGINE BLOCK
DESCRIPTION.........................39
STANDARD PROCEDURE - CYLINDER BORE
HONING............................39
CLEANING............................39
INSPECTION..........................40
CONNECTING ROD BEARINGS
STANDARD PROCEDURE - CONNECTING
ROD BEARING - FITTING...............40
CRANKSHAFT
DESCRIPTION.........................42
REMOVAL.............................43
INSPECTION..........................43
INSTALLATION.........................43
CRANKSHAFT MAIN BEARINGS
STANDARD PROCEDURE
MAIN BEARING - FITTING...............45
CRANKSHAFT OIL SEAL - FRONT
REMOVAL.............................46
INSTALLATION.........................47
CRANKSHAFT OIL SEAL - REAR
REMOVAL.............................48
INSTALLATION.........................48
FLEX PLATE
REMOVAL.............................49
INSTALLATION.........................49
PISTON & CONNECTING ROD
DESCRIPTION.........................49
STANDARD PROCEDURE
CONNECTING ROD BEARING - FITTING . . . 49
STANDARD PROCEDURE - PISTON
FITTING.............................50
REMOVAL.............................50
CLEANING............................51
INSPECTION..........................51
INSTALLATION.........................51
PISTON RINGS
STANDARD PROCEDURE - PISTON RING
FITTING.............................52
VIBRATION DAMPER
REMOVAL.............................54
INSTALLATION.........................55
STRUCTURAL COVER
DESCRIPTION.........................55
OPERATION...........................55
REMOVAL.............................55
INSTALLATION.........................55
FRONT MOUNT
REMOVAL.............................56
INSTALLATION.........................57
REAR MOUNT
REMOVAL.............................57
INSTALLATION.........................57
LUBRICATION
DESCRIPTION.........................57
OPERATION...........................58DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - ENGINE OIL
LEAK...............................60
DIAGNOSIS AND TESTING - ENGINE OIL
PRESSURE..........................60
DIAGNOSIS AND TESTING - REAR SEAL
AREA LEAKS.........................61
OIL
STANDARD PROCEDURE - ENGINE OIL.....61
OIL FILTER
REMOVAL.............................63
INSTALLATION.........................63
OIL PAN
DESCRIPTION.........................63
REMOVAL.............................63
CLEANING............................63
INSPECTION..........................63
INSTALLATION.........................64
OIL PRESSURE SENSOR/SWITCH
DESCRIPTION.........................65
OPERATION...........................65
REMOVAL.............................65
INSTALLATION.........................65
OIL PUMP
REMOVAL.............................65
DISASSEMBLY.........................65
INSPECTION..........................66
ASSEMBLY............................67
INSTALLATION.........................67
INTAKE MANIFOLD
DESCRIPTION.........................68
DIAGNOSIS AND TESTING - INTAKE
MANIFOLD LEAKS.....................68
REMOVAL.............................68
INSTALLATION.........................69
EXHAUST MANIFOLD
DESCRIPTION.........................69
REMOVAL.............................69
INSTALLATION.........................70
VALVE TIMING
DESCRIPTION.........................71
OPERATION...........................71
STANDARD PROCEDURE
MEASURING TIMING CHAIN WEAR.......71
SERVICE PROCEDURES...............72
BALANCE SHAFT
REMOVAL.............................74
INSTALLATION.........................74
TIMING BELT / CHAIN COVER(S)
REMOVAL.............................74
INSTALLATION.........................76
IDLER SHAFT
REMOVAL.............................77
INSTALLATION.........................77
TIMING BELT/CHAIN AND SPROCKET(S
REMOVAL.............................77
INSPECTION..........................79
INSTALLATION.........................80
9 - 2 ENGINE - 3.7LKJ

CONDITION POSSIBLE CAUSE CORRECTION
5. Incorrect cam timing. 5. (Refer to 9 - ENGINE/VALVE
TIMING - STANDARD
PROCEDURE).
1. ENGINE LOSS OF POWER 1. Dirty or incorrectly gapped spark
plugs.1. (Refer to 8 - ELECTRICAL/
IGNITION CONTROL/SPARK PLUG
- CLEANING).
2. Dirt or water in fuel system. 2. Clean system and replace fuel
filter.
3. Faulty fuel pump. 3. (Refer to 14 - FUEL SYSTEM/
FUEL DELIVERY/FUEL PUMP -
DIAGNOSIS AND TESTING).
4. Blown cylinder head gasket. 4. Replace cylinder head gasket.
5. Low compression. 5. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING), repair
as necessary.
6. Burned, warped or pitted valves. 6. Replace as necessary.
7. Plugged or restricted exhaust
system.7. Inspect and replace as
necessary.
8. Faulty coil. 8. (Refer to 8 - ELECTRICAL/
IGNITION CONTROL/IGNITION
COIL - REMOVAL).
9. Incorrect cam timing. 9. Refer to Engine TIming in this
section.
1. ENGINE MISSES ON
ACCELERATION1. Spark plugs dirty or incorrectly
gapped.1. (Refer to 8 - ELECTRICAL/
IGNITION CONTROL/SPARK PLUG
- CLEANING).
2. Dirt in fuel system. 2. Clean fuel system.
3. Burned, warped or pitted valves. 3. Replcae as necessary.
4. Faulty coil. 4. (Refer to 8 - ELECTRICAL/
IGNITION CONTROL/IGNITION
COIL - REMOVAL).
1. ENGINE MISSES AT HIGH
SPEED1. Spark plugs dirty or incorrectly
gapped.1. (Refer to 8 - ELECTRICAL/
IGNITION CONTROL/SPARK PLUG
- CLEANING).
2. Faulty coil. 2. (Refer to 8 - ELECTRICAL/
IGNITION CONTROL/IGNITION
COIL - REMOVAL).
3. Dirt or water in fuel system. 3. Clean system and replace fuel
filter.
KJENGINE - 3.7L 9 - 5
ENGINE - 3.7L (Continued)

DIAGNOSIS AND TESTING - ENGINE DIAGNOSIS - MECHANICAL
CONDITION POSSIBLE CAUSES CORRECTIONS
NOISY VALVES 1. High or low oil level in
crankcase.1. (Refer to LUBRICATION &
MAINTENANCE/FLUID TYPES -
SPECIFICATIONS).
2. Thin or diluted oil. 2. Change oil and filter.
3. Low oil pressure. 3. Check oil pump, if Ok, check rod
and main bearings for excessive
wear.
4. Dirt in lash adjusters. 4. Clean or replace as necessary.
5. Worn rocker arms. 5. Replace as necessary.
7. Worn valve guides. 7. (Refer to 9 - ENGINE/CYLINDER
HEAD/INTAKE/EXHAUST VALVES
& SEATS - STANDARD
PROCEDURE).
8. Excessive runout of valve seats
on valve faces.8. Service valves and valve seats.
(Refer to 9 - ENGINE/CYLINDER
HEAD/INTAKE/EXHAUST VALVES
& SEATS - STANDARD
PROCEDURE).
ENGINE VIBRATION 1. Counter Balance Shaft not timed
properly1. Refer to Engine Timing in this
section
CONNECTING ROD NOISE 1. Insufficient oil supply. 1. (Refer to LUBRICATION &
MAINTENANCE/FLUID TYPES -
SPECIFICATIONS).
2. Low oil pressure. 2. Check oil pump, if Ok, check rod
and main bearings for excessive
wear.
3. Thin or diluted oil. 3. Change oil and filter.
4. Excessive bearing clearance. 4. Replace as necessary.
5. Connecting rod journal
out-of-round.5. Service or replace crankshaft.
6. Misaligned connecting rods. 6. Replace bent connecting rods.
MAIN BEARING NOISE 1. Insufficient oil supply. 1. (Refer to LUBRICATION &
MAINTENANCE/FLUID TYPES -
SPECIFICATIONS).
2. Low oil pressure. 2. Check oil pump, if Ok, check rod
and main bearings for excessive
wear.
3. Thin or diluted oil. 3. Change oil and filter.
4. Excessive bearing clearance. 4. Replace as necessary.
5. Excessive end play. 5. Check thrust washers for wear.
6. Crankshaft journal out-of round. 6. Service or replace crankshaft.
7. Loose flywheel or torque
converter.7. Tighten to correct torque
9 - 6 ENGINE - 3.7LKJ
ENGINE - 3.7L (Continued)

CONDITION POSSIBLE CAUSES CORRECTION
OIL PUMPING AT RINGS; SPARK
PLUGS FOULING1. Worn or damaged rings. 1. Hone cylinder bores and replace
rings.
2. Carbon in oil ring slots. 2. Replace rings (Refer to 9 -
ENGINE/ENGINE BLOCK/PISTON
RINGS - STANDARD
PROCEDURE).
3. Incorrect ring size installed. 3. Replace rings (Refer to 9 -
ENGINE/ENGINE BLOCK/PISTON
RINGS - STANDARD
PROCEDURE).
4. Worn valve guides. 4. Ream guides and replace valves
(Refer to 9 - ENGINE/CYLINDER
HEAD/INTAKE/EXHAUST VALVES
& SEATS - STANDARD
PROCEDURE).
5. Leaking valve guide seals. 5. Replace valve guide seals.
DIAGNOSIS AND TESTING - CYLINDER
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.
(3) Secure the throttle in the wide-open position.
(4) Disable the fuel system (Refer to 14 - FUEL
SYSTEM/FUEL DELIVERY - DESCRIPTION).
(5) Remove the ASD relay (Refer to 8 - ELECTRI-
CAL/IGNITION CONTROL/AUTO SHUT DOWN
RELAY - REMOVAL).
(6) Insert a compression pressure gauge and rotate
the engine with the engine starter motor for three
revolutions.
(7) Record the compression pressure on the 3rd
revolution. Continue the test for the remaining cylin-
ders.
(8) (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
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 .
9 - 8 ENGINE - 3.7LKJ
ENGINE - 3.7L (Continued)