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Jeep Wrangler TJ. Manual - part 455

Fig. 2 Exhaust System - 4.0L

1 - TAILPIPE
2 - MUFFLER
3 - CATALYTIC CONVERTER

4 - MINI CATALYTIC CONVERTER
5 - EXHAUST PIPE

EXHAUST SYSTEM

11 - 3

EXHAUST SYSTEM (Continued)

DIAGNOSIS AND TESTING - EXHAUST SYSTEM

EXHAUST SYSTEM DIAGNOSIS CHART

CONDITION

POSSIBLE CAUSE

CORRECTION

EXCESSIVE EXHAUST NOISE OR
LEAKING EXHAUST GASES

1. 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.

SPECIFICATIONS

TORQUE

DESCRIPTION

N·m

Ft.

In.

Lbs.

Bolts, Crossmember to Sill

Nuts, Crossmember to
Transmission Mount

Nuts, Exhaust Pipe to

Manifold

Nuts/Bolt, Exhaust Manifold to
Engine

#6&7

#1,2,3,4,5,8,9,10&11

Nuts, Exhaust Pipe to
Catalytic Converter Flange

28.5

Clamp, Tailpipe to Rear
Tailpipe Hanger

Oxygen Sensors

Heat Shields

CATALYTIC CONVERTER

DESCRIPTION

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 the

11 - 4

EXHAUST SYSTEM

EXHAUST SYSTEM (Continued)

cause of the damage at the same time the converter
is replaced. Also, inspect all other components of the
exhaust system for heat damage.

The catalytic converter and muffler are serviced as

an assembly.

Unleaded gasoline must be used to avoid contami-

nating the catalyst core.

REMOVAL

REMOVAL - 2.4L

WARNING: THE NORMAL OPERATING TEMPERA-
TURE OF THE EXHAUST SYSTEM IS VERY HIGH.
THEREFORE, NEVER ATTEMPT TO SERVICE ANY
PART OF THE EXHAUST SYSTEM UNTIL IT IS
COOLED. SPECIAL CARE SHOULD BE TAKEN
WHEN WORKING NEAR THE CATALYTIC CON-
VERTER. THE TEMPERATURE OF THE CONVERTER
RISES TO A HIGH LEVEL AFTER A SHORT PERIOD
OF ENGINE OPERATION TIME.

WARNING: IF TORCHES ARE USED WHEN WORK-
ING ON THE EXHAUST SYSTEM, DO NOT ALLOW
THE FLAME NEAR THE FUEL LINES.

CAUTION: When servicing exhaust system compo-
nents, disconnect the oxygen sensor connector(s).
Allowing the exhaust system to hang by the oxygen
sensor harness will damage the wiring and/or sen-
sor.

(1) Disconnect the oxygen sensors.
(2) Remove the two bolts and flanged nuts at the

manifold (Fig. 3).

(3) Remove the two bolts and flanged nuts at the

flange.

(4) Remove the mini catalyst assembly from the

vehicle.

(5) Slide exhaust pipe forward until exhaust pipe

hanger

disengages

from

transmission

support.

Remove exhaust pipe and catalytic converter from
vehicle.

REMOVAL - 4.0L

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 studs and nuts with a Mopar

rust penetrant. Allow 5 minutes for penetration.

(3) Remove the oxygen sensors from the exhaust

pipe and the catalytic converter.

(4) Disconnect the exhaust pipe from the engine

exhaust manifold (Fig. 4).

(5) Remove mini catalytic converter flange retain-

ing nuts (Fig. 4).

(6) Slide exhaust pipe forward until exhaust pipe

hanger

disengages

from

transmission

support.

Remove exhaust pipe and catalytic converter from
vehicle.

Fig. 3 2.4L Exhaust Pipe and Catalytic Converter -

4x4

1- FLANGED NUT
2- MINI CATALYST ASSEMBLY
3- BOLT
4- HANGER
5- NUT

EXHAUST SYSTEM

11 - 5

CATALYTIC CONVERTER (Continued)

INSTALLATION

INSTALLATION - 2.4L

(1) Position the mini catalytic converter assembly

onto the exhaust pipe flange and the exhaust mani-
fold. Tighten the nuts to 31 N·m (23 ft.lbs.) torque.
Tighten the flange nuts to 28 N·m (21 ft. lbs.).

(2) Connect oxygen sensor wiring.
(3) Lower the vehicle.
(4) Start engine and inspect for leaks. Repair

exhaust leaks as necessary.

(5) Check the exhaust system for contact with the

body panels. Make the necessary adjustments, if
needed.

INSTALLATION - 4.0L

(1) Position exhaust pipe and catalytic converter

into vehicle.

(2) Insert exhaust pipe hanger into transmission

support (Fig. 4).

(3) Install exhaust pipe onto exhaust manifold DO

NOT tighten bolts at this time.

(4) Position muffler flange onto catalytic converter

flange and install retaining bolts and nuts (Fig. 4).
DO NOT tighten nuts at this time.

(5) Make sure the exhaust system is aligned and

has the proper clearance. The minimum clearance is
25mm (1 inch).

(6) Tighten muffler to catalytic converter flange

retaining nuts to 28.5 N·m (21 ft. lbs.).

(7) Tighten exhaust pipe to exhaust manifold

mounting bolts to 31 N·m (23 ft. lbs.).

(8) Install the oxygen sensors in the exhaust pipe

and catalytic converter.

(9) Lower vehicle.
(10) Start engine and inspect for leaks. Repair

exhaust leaks as necessary.

(11) Check the exhaust system for contact with the

body panels. Make the necessary adjustments, if
needed.

EXHAUST PIPE

REMOVAL

REMOVAL - 2.4L

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 studs and nuts with a Mopar

rust penetrant. Allow 5 minutes for penetration.

(3) Remove the oxygen sensors from the exhaust

pipe and the catalytic converter.

(4) Disconnect the exhaust pipe from the engine

exhaust manifold (Fig. 5).

(5) Remove catalytic converter to muffler flange

retaining nuts (Fig. 5).

(6) Slide exhaust pipe forward until exhaust pipe

hanger

disengages

from

transmission

support.

Remove exhaust pipe and catalytic converter from
vehicle.

Fig. 4 Exhaust Pipe and Catalytic Converter - 4.0L

1 - CATALYTIC CONVERTER
2 - TRANSMISSION SUPPORT
3 - EXHAUST HANGER
4 - EXHAUST PIPE

11 - 6

EXHAUST SYSTEM

CATALYTIC CONVERTER (Continued)

Content .. 453 454 455 456 ..