2002 JEEP LIBERTY Engine

EXHAUST SYSTEM
TABLE OF CONTENTS
page page
EXHAUST SYSTEM
DESCRIPTION..........................1
DIAGNOSIS AND TESTING - EXHAUST
SYSTEM.............................2
CATALYTIC CONVERTER
DESCRIPTION - CATALYTIC CONVERTER.....2
REMOVAL.............................2
INSPECTION...........................3
INSTALLATION..........................3CROSS-OVER PIPE
REMOVAL.............................4
INSTALLATION..........................4
HEAT SHIELDS
DESCRIPTION..........................4
MUFFLER
DESCRIPTION..........................4
REMOVAL.............................4
INSTALLATION..........................5
EXHAUST SYSTEM
DESCRIPTION
The basic exhaust system consists of an engine
exhaust manifold, exhaust down pipe, exhaust pipe,
exhaust heat shield(s), muffler and exhaust tailpipe
The exhaust system uses a single muffler.
The exhaust system must be properly aligned to
prevent stress, leakage and body contact. If the sys-
tem contacts any body panel, it will transfer objec-
tionable noises originating from the engine to the
body.
When inspecting an exhaust system, critically
inspect for cracked or loose joints, stripped screw or
bolt threads, corrosion damage and worn, cracked orbroken hangers. Replace all components that are
badly corroded or damaged. DO NOT attempt to
repair.
When replacement is required, use original equip-
ment parts (or equivalent). This will assure proper
alignment and provide acceptable exhaust noise lev-
els.
CAUTION: Avoid application of rust prevention com-
pounds or undercoating materials to exhaust sys-
tem floor pan exhaust heat shields. Light overspray
near the edges is permitted. Application of coating
will result in excessive floor pan temperatures and
objectionable fumes.
KJEXHAUST SYSTEM 11s - 1

DIAGNOSIS AND TESTING - EXHAUST SYSTEM
EXHAUST SYSTEM DIAGNOSIS CHART
CONDITION POSSIBLE CAUSE CORRECTION
EXCESSIVE EXHAUST NOISE OR
LEAKING EXHAUST GASES1. Leaks at pipe joints. 1. Tighten clamps/bolts to specified
torque at leaking joints.
2. Rusted or blown out muffler. 2. Replace muffler. Inspect exhaust
system.
3. Broken or rusted out exhaust
pipe.3. Replace exhaust pipe.
4. Exhaust pipe leaking at manifold
flange.4. Tighten/replace flange attaching
nuts/bolts.
5. Exhaust manifold cracked or
broken.5. Replace exhaust manifold.
6. Leak between exhaust manifold
and cylinder head.6. Tighten exhaust manifold to
cylinder head bolts.
7. Catalytic converter rusted or
blown out.7. Replace catalytic converter assy.
8. Restriction in exhaust system. 8. Remove restriction, if possible.
Replace restricted part if necessary.
CAUTION:
When servicing and replacing exhaust system components, disconnect the oxygen sensor connector(s). Allowing
the exhaust to hang by the oxygen sensor wires will damage the harness and/or sensor.
CATALYTIC CONVERTER
DESCRIPTION - CATALYTIC CONVERTER
WARNING: THE NORMAL OPERATING TEMPERA-
TURE OF THE EXHAUST SYSTEM IS VERY HIGH.
THEREFORE, NEVER WORK AROUND OR ATTEMPT
TO SERVICE ANY PART OF THE EXHAUST SYSTEM
UNTIL IT IS COOLED. SPECIAL CARE SHOULD BE
TAKEN WHEN WORKING NEAR THE CATALYTIC
CONVERTER. THE TEMPERATURE OF THE CON-
VERTER RISES TO A HIGH LEVEL AFTER A SHORT
PERIOD OF ENGINE OPERATION TIME.
CAUTION: DO NOT remove spark plug wires from
plugs or by any other means short out cylinders.
Failure of the catalytic converter can occur due to a
temperature increase caused by unburned fuel
passing through the converter.
The stainless steel catalytic converter body is
designed to last the life of the vehicle. Excessive heat
can result in bulging or other distortion, but exces-
sive heat will not be the fault of the converter. If
unburned fuel enters the converter, overheating may
occur. If a converter is heat-damaged, correct thecause of the damage at the same time the converter
is replaced. Also, inspect all other components of the
exhaust system for heat damage.
Unleaded gasoline must be used to avoid con-
taminating the catalyst core.
50 State emission vehicles incorporate two mini
catalytic converters located after the exhaust mani-
folds and before the inline catalytic converter.
REMOVAL
WARNING: IF TORCHES ARE USED WHEN WORK-
ING ON THE EXHAUST SYSTEM, DO NOT ALLOW
THE FLAME NEAR THE FUEL LINES.
(1) Raise and support the vehicle.
(2) Saturate the bolts and nuts with heat valve
lubricant. Allow 5 minutes for penetration.
(3) Remove the bolts from the crossover pipe to the
catalytic converter connection.
(4) Disconnect oxygen sensor wiring.
(5) Loosen and remove the nuts from the clamp
that hold the catalytic converter to the exhaust pipe
flange connection.
11s - 2 EXHAUST SYSTEMKJ
EXHAUST SYSTEM (Continued)

2.4L ENGINES
(1) Disconnect the oxygen sensors.
(2) Remove the two bolts and flanged nuts at the
manifold (Fig. 1).
(3) Lower the catalyst assembly and slide out of
the mount at the transmission (if equipped).
(4) Remove the catalyst assembly from the vehicle.
3.7L ENGINES
NOTE: Do not remove nut from T-Bolt. Only remove
nut far enough, so that the T end can be removed
from the clamp.
(1) Remove the T bolt end of the fastener, from the
clamp.
(2) Spread the clamp, and remove the catalytic
converter from the vehicle.
(3) Discard the clamp (Fig. 2).
NOTE: The catalytic converter to exhaust manifold
clamp is not reusable. Always use a new clamp
when reinstalling the catalytic converter.
INSPECTION
Look at the stainless steel body of the converter,
inspect for bulging or other distortion that could be a
result of overheating. If the converter has a heat
shield attached make sure it is not bent or loose.
If you suspect internal damage to the catalyst, tap-
ping the bottom of the catalyst with a rubber mallet
may indicate a damaged core.
INSTALLATION
(1) Position the catalytic converter onto the
exhaust pipe flange connection. Tighten the nuts to
28 N´m (250 in. lbs.) torque.
(2) Install the muffler onto the catalytic converter
until the alignment tab is inserted into the align-
ment slot.
(3) Install the exhaust clamp at the muffler and
catalytic converter connection. Tighten the clamp
nuts to 47 N´m (35 ft. lbs.) torque.
(4) Connect oxygen sensor wiring.
(5) Lower the vehicle.
(6) Start the engine and inspect for exhaust leaks
and exhaust system contact with the body panels.
Adjust the alignment, if needed.
Fig. 1 2.4L CATALYST ASSEMBLY - 4x4
1- FLANGED NUT
2- CATALYST ASSEMBLY
3- BOLT
4- HANGER
5- NUT
Fig. 2 Catalyst Removal
1 - V-Clamp
2 - Catalytic Converter
3 - Flange
4 - Crossover Pipe
5 - T-Bolt
KJEXHAUST SYSTEM 11s - 3
CATALYTIC CONVERTER (Continued)

CROSS-OVER PIPE
REMOVAL
WARNING: IF TORCHES ARE USED WHEN WORK-
ING ON THE EXHAUST SYSTEM, DO NOT ALLOW
THE FLAME NEAR THE FUEL LINES.
WARNING: THE NORMAL OPERATING TEMPERA-
TURE OF THE EXHAUST SYSTEM IS VERY HIGH.
THEREFORE, NEVER WORK AROUND OR ATTEMPT
TO SERVICE ANY PART OF THE EXHAUST SYSTEM
UNTIL IT IS COOLED. SPECIAL CARE SHOULD BE
TAKEN WHEN WORKING NEAR THE CATALYTIC
CONVERTER. THE TEMPERATURE OF THE CON-
VERTER RISES TO A HIGH LEVEL AFTER A SHORT
PERIOD OF ENGINE OPERATION TIME.
(1) Raise and support the vehicle.
(2) Saturate the bolts and nuts with lubricant.
Allow 5 minutes for penetration.
(3) Remove the retaining fasteners holding cross-
over pipe to exhaust pipe.
(4) Remove the fasteners from the crossover pipe
to the catalytic converter connection.
(5) Remove the crossove pipe from the hanger
insulator (Fig. 3).
INSTALLATION
WARNING: IF TORCHES ARE USED WHEN WORK-
ING ON THE EXHAUST SYSTEM, DO NOT ALLOW
THE FLAME NEAR THE FUEL LINES.
WARNING: THE NORMAL OPERATING TEMPERA-
TURE OF THE EXHAUST SYSTEM IS VERY HIGH.
THEREFORE, NEVER WORK AROUND OR ATTEMPT
TO SERVICE ANY PART OF THE EXHAUST SYSTEM
UNTIL IT IS COOLED. SPECIAL CARE SHOULD BE
TAKEN WHEN WORKING NEAR THE CATALYTIC
CONVERTER. THE TEMPERATURE OF THE CON-
VERTER RISES TO A HIGH LEVEL AFTER A SHORT
PERIOD OF ENGINE OPERATION TIME.
(1) Install the crossove pipe into the hanger insu-
lator.
(2) Install and torque the fasteners in the cross-
over pipe to the left and right catalytic converter con-
nection.
(3) Install and torque the retaining fasteners hold-
ing the crossover pipe to exhaust pipe.
(4) Lower vehicle..
(5) Start engine and check for leaks.
HEAT SHIELDS
DESCRIPTION
Heat shields (Fig. 4) are needed to protect both the
vehicle and the environment from the high tempera-
tures developed by the catalytic converter. The cata-
lytic converter releases additional heat into the
exhaust system. Under severe operating conditions,
the temperature increases in the area of the con-
verter. Such conditions can exist when the engine
misfires or otherwise does not operate at peak effi-
ciency.
MUFFLER
DESCRIPTION
The 2.4L and 3.7L engine uses a galvanized steel
muffler (Fig. 5) to control exhaust noise levels and
exhaust back pressure.
REMOVAL
All original equipment exhaust systems are manu-
factured with the exhaust tailpipe welded to the muf-
fler. Service replacement mufflers and exhaust
tailpipes are either clamped together or welded
together.Fig. 3 Crossover Pipe
1 - Crossover-toCatalytic Converter flange
2 - Crossover Pipe
3 - Crossover Pipe to Tail Pipe Flange
4 - Hanger Bracket
11s - 4 EXHAUST SYSTEMKJ

FRAMES & BUMPERS
TABLE OF CONTENTS
page page
FRONT FASCIA
REMOVAL.............................1
INSTALLATION..........................2
REAR FASCIA
REMOVAL.............................2
INSTALLATION..........................2
REAR FASCIA SUPPORT
REMOVAL.............................3
INSTALLATION..........................3
FRAME
SPECIFICATIONS
SPECIFICATIONS - FRAME DIMENSIONS . . . 3
SPECIFICATIONS - TORQUE.............6
FRONT SKID PLATE
REMOVAL.............................6
INSTALLATION..........................6
ENGINE CRADLE CROSSMEMBER
REMOVAL.............................6
INSTALLATION..........................6TRANSFER CASE SKID PLATE
REMOVAL.............................7
INSTALLATION..........................7
REAR CROSSMEMBER
REMOVAL.............................7
INSTALLATION..........................7
FRONT TOW HOOK
REMOVAL.............................8
INSTALLATION..........................8
REAR TOW HOOK
REMOVAL.............................8
INSTALLATION..........................8
TRAILER HITCH
REMOVAL.............................9
INSTALLATION..........................9
FUEL TANK SKID PLATE
REMOVAL.............................9
INSTALLATION..........................9
FRONT FASCIA
REMOVAL
(1) Remove the grille. (Refer to 23 - BODY/EXTE-
RIOR/GRILLE - REMOVAL)
(2) Raise and support vehicle.
(3) Remove the front wheel opening flare moldings.
(Refer to 23 - BODY/EXTERIOR/FRONT WHEEL
OPENING FLARE MOLDINGS - REMOVAL)
(4) Remove the four screws through the lower air
dam (Fig. 1).
(5) Disconnect the electrical connectors:
²Fascia to grille opening reinforcement. (Fig. 1)
²Side repeater lights, both sides, if equipped.
(Fig. 2)
(6) Remove the six push pins from the grill sup-
port.
(7) Remove the rivets attaching the air dam to the
wheelhouse splash shield.
(8) Release the support tabs beneath the head-
lamps.
(9) Release the inner support clips from within the
fascia between the lights (Fig. 2).
(10) Remove the fascia.
Fig. 1 FRONT FASCIA
1 - ELECTRICAL CONNECTOR
2 - PUSH PINS
3 - FRONT FASCIA ASSEMBLY
4 - LOWER SCREWS
5 - PLASTIC RIVETS (2)
6 - INNER SUPPORT CLIPS
7 - SUPPORT TABS
KJFRAMES & BUMPERS 13 - 1

SPECIFICATIONS - TORQUE
DESCRIPTION N´m Ft. Lbs. In. Lbs.
ENGINE CRADLE CROSSMEMBER INNER RAIL BOLTS 47 35 Ð
ENGINE CRADLE CROSSMEMBER MOUNTING BOLTS 122 90 Ð
ENGINE MOUNT THROUGH BOLTS/NUTS 88 65 Ð
FRONT SKID PLATE BOLTS 61 45 Ð
FRONT TOW HOOK NUTS/BOLT 61 45 Ð
FUEL TANK SKID PLATE 88 65 Ð
REAR CROSSMEMBER BOLTS 47 35 Ð
REAR TOW HOOK BOLTS 88 65 Ð
TRAILER HITCH BOLTS 88 65 Ð
TRANSFER CASE SKID PLATE BOLTS 34 25 Ð
TRANSMISSION MOUNT THROUGH BOLT/NUT 88 65 Ð
FRONT SKID PLATE
REMOVAL
(1) Raise and support the vehicle.
(2) Remove the skid plate bolts and remove the
skid plate. (Fig. 7)
INSTALLATION
(1) Install the skid plate.
(2) Install the bolts and tighten to 61 N´m (45 ft.
lbs.).
ENGINE CRADLE
CROSSMEMBER
REMOVAL
(1) Install a suitable engine support tool.
(2) Raise and support the vehicle.
(3) Remove the lower control arms. (Refer to 2 -
SUSPENSION/FRONT/LOWER CONTROL ARM -
REMOVAL)
(4) Remove the sway bar. (Refer to 2 - SUSPEN-
SION/FRONT/STABILIZER BAR - REMOVAL)
(5) Remove the front axle, if equipped. (Refer to 3 -
DIFFERENTIAL & DRIVELINE/FRONT AXLE -
REMOVAL)
(6) Remove the power steering rack. (Refer to 19 -
STEERING/GEAR - REMOVAL)
(7) Loosen the engine mount through bolts.
(8) Support the engine cradle with a suitable lift-
ing device.
(9) Using a grease pencil or equivalent, mark the
location of the engine support cradle.
(10) Remove the engine cradle bolts and remove
the engine cradle.
INSTALLATION
(1) Raise and support the vehicle.
(2) Using a suitable lifting device raise the engine
cradle into the vehicle while lining up the engine
mount through bolts.
Fig. 7 SKID PLATE
1 - SKID PLATE
2 - BOLTS (4)
13 - 6 FRAMES & BUMPERSKJ
FRAME (Continued)

(3) Align the engine cradle to the marks made dur-
ing removal and install the mounting and inner rail
bolts.
(4) Tighten the mounting bolts to 122 N´m (90 ft.
lbs.).
(5) Tighten the inner rail bolts to 47 N´m (35 ft.
lbs.).
(6) Tighten the engine mount through bolts to 88
N´m (65 ft. lbs.).
(7) Install the power steering rack. (Refer to 19 -
STEERING/GEAR - INSTALLATION)
(8) Install the front axle, if equipped. (Refer to 3 -
DIFFERENTIAL & DRIVELINE/FRONT AXLE -
INSTALLATION)
(9) Install the stabilizer bar. (Refer to 2 - SUS-
PENSION/FRONT/STABILIZER BAR - INSTALLA-
TION)
(10) Install the lower control arms. (Refer to 2 -
SUSPENSION/FRONT/LOWER CONTROL ARM -
INSTALLATION)
(11) Lower the vehicle and remove the engine sup-
port tool.
TRANSFER CASE SKID PLATE
REMOVAL
(1) Remove the bolts and remove the skid plate.
(Fig. 8)
INSTALLATION
(1) Install the skid plate.
(2) Install the bolts and tighten to 34 N´m (25 ft.
lbs.).
REAR CROSSMEMBER
REMOVAL
(1) Raise and support the vehicle.
(2) Support the transmission with a suitable lifting
device.
(3) Remove the transmission mount through bolt.
(4) Remove the crossmember bolts and remove the
crossmember. (Fig. 9)
INSTALLATION
(1) Install the crossmember and install the bolts.
(2) Tighten the bolts to 47 N´m (35 ft. lbs.)
(3) Install transmission mount through bolt and
tighten to 88 N´m (65 ft. lbs.).
Fig. 8 SKID PLATE
1 - SKID PLATE
2 - BOLTS
Fig. 9 CROSS MEMBER
1 - CROSSMEMBER
2 - BOLTS
KJFRAMES & BUMPERS 13 - 7
ENGINE CRADLE CROSSMEMBER (Continued)

OPERATION
Fuel is picked up in the fuel tank by the fuel pump
module. This module is located on the bottom of the
fuel tank.
A fuel return system is provided within the fuel
pump module using check valves. A separate fuel
return line from the engine to the tank is not used.
The fuel pressure regulator and the main fuel filter
are not combined. They are separate items.
The fuel tank assembly consists of: the fuel tank,
fuel pump module assembly, fuel pump module lock
ring/gasket, ORVR components. Refer to 25, Emis-
sion Control System for ORVR information.
A fuel filler/vent tube assembly using a pressure/
vacuum, 1/4 turn fuel filler cap is used. The fuel
filler tube contains a flap door located below the fuel
fill cap. A one-way check valve is installed into the
tanks fuel fill fitting.
Also to be considered part of the fuel system is the
evaporation control system and ORVR system. This
is designed to reduce the emission of fuel vapors into
the atmosphere. The description and function of the
Evaporative Control System is found in 25, Emission
Control Systems.
Both fuel filters (mounted to front of fuel tank, and
inside the bottom fuel pump module) are designed for
extended service. They do not require normal sched-
uled maintenance. The bottom section of the fuel
pump module (with included filter) should only be
replaced if a diagnostic procedure indicates to do so.
Also, the fuel filter mounted to the front of the fuel
tank should only be replaced if a diagnostic proce-
dure indicates to do so.
DIAGNOSIS AND TESTING - FUEL PRESSURE
LEAK DOWN TEST
Use this test in conjunction with the Fuel Pump
Pressure Test and Fuel Pump Capacity Test.
Check Valve Operation:The electric fuel pump
outlet contains a one-way check valve to prevent fuel
flow back into the tank and to maintain fuel supply
line pressure (engine warm) when pump is not oper-
ational. It is also used to keep the fuel supply line
full of gasoline when pump is not operational. After
the vehicle has cooled down, fuel pressure may drop
to 0 psi (cold fluid contracts), but liquid gasoline will
remain in fuel supply line between the check valve
and fuel injectors.Fuel pressure that has
dropped to 0 psi on a cooled down vehicle
(engine off) is a normal condition.When the elec-
tric fuel pump is activated, fuel pressure should
immediately(1±2 seconds) rise to specification.
Abnormally long periods of cranking to restart a
hotengine that has been shut down for a short
period of time may be caused by:
²Fuel pressure bleeding past a fuel injector(s).²Fuel pressure bleeding past the check valve in
the fuel pump module.
(1) Disconnect the fuel inlet line at fuel rail. Refer
to Quick Connect Fittings for procedures. On some
engines, air cleaner housing removal may be neces-
sary before fuel line disconnection.
(2) Obtain correct Fuel Line Pressure Test Adapter
Tool Hose. Tool number 6539 is used for 5/16º fuel
lines and tool number 6631 is used for 3/8º fuel lines.
(3) Connect correct Fuel Line Pressure Test
Adapter Tool Hose between disconnected fuel line
and fuel rail (Fig. 2).
(4) Connect the 0-414 kPa (0-60 psi) fuel pressure
test gauge (from Gauge Set 5069) to the test port on
the appropriate Adaptor Tool.The DRBtIII Scan
Tool along with the PEP module, the 500 psi
pressure transducer, and the transducer-to-test
port adapter may also be used in place of the
fuel pressure gauge.
The fittings on both tools must be in good
condition and free from any small leaks before
performing the proceeding test.
(5) Start engine and bring to normal operating
temperature.
(6) Observe test gauge. Normal operating pressure
should be 339 kPa +/±34 kPa (49.2 psi +/±5 psi).
(7) Shut engine off.
Fig. 2 CONNECTING ADAPTER TOOLÐTYPICAL
1 - VEHICLE FUEL LINE
2 - TEST PORT ªTº
3 - SPECIAL TOOL 6923, 6631, 6541 OR 6539
4 - FUEL PRESSURE TEST GAUGE
5 - FUEL LINE CONNECTION AT RAIL
6 - FUEL RAIL
KJFUEL DELIVERY 14 - 3
FUEL DELIVERY (Continued)