93ZJ-Secc-11-Exhaust-System-and-Intake-Manifold.pdf

EXHAUST SYSTEM AND INTAKE MANIFOLD

11 - 1

EXHAUST SYSTEM AND INTAKE MANIFOLD

CONTENTS

page

EXHAUST SYSTEM ....................... 1

EXHAUST SYSTEM DIAGNOSIS ............. 3

SERVICE PROCEDURES ................... 4

TORQUE SPECIFICATIONS ................ 10

EXHAUST SYSTEM

GENERAL INFORMATION

The basic exhaust system consists of exhaust mani-

fold(s), exhaust pipe with oxygen sensor, catalytic con-

verter, heat shield(s), muffler and tailpipe (Fig. 1 or

2).

Fig. 2 Exhaust System (5.2L Engine)

Fig. 1 Exhaust System (4.0L Engine)

When inspecting an exhaust system, critically in-

spect for cracked or loose joints, stripped screw or bolt

threads, corrosion damage and worn, cracked or bro-

ken 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 their equivalent). This will assure

proper alignment and provide acceptable exhaust

noise levels.

The exhaust system uses a single muffler with a

single monolithic-type catalytic converter.

The 4.0L engines use a seal between the exhaust

manifold and exhaust pipe to assure a tight seal and

strain free connections.

The 5.2L exhaust manifolds are equipped with ball

flange outlets to assure a tight seal and strain free

connections.

The exhaust system must be properly aligned to

prevent stress, leakage and body contact. If the sys-

tem contacts any body panel, it may amplify objec-

tionable noises originating from the engine or body.

CAUTION: Avoid application of rust prevention com-

pounds or undercoating materials to exhaust sys-

tem floor pan heat shields. Light overspray near the

edges is permitted. Application of coating will result

in excessive floor pan temperatures and objection-

able fumes.

11 - 2 EXHAUST SYSTEM AND INTAKE MANIFOLD

CATALYTIC CONVERTER

The stainless steel catalytic converter body is de-

signed to last the life of the vehicle. Excessive heat

can result in bulging or other distortion, but excessive

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 cause 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 contami-

nating the catalyst core.

HEAT SHIELDS

Heat shields are needed to protect both the vehicle

and the environment from the high temperatures de-

veloped by the catalytic converter (Fig. 3 or 4). The

catalytic 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.

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.

DO NOT allow the engine to operate at fast idle for

extended periods (over 5 minutes). This condition

may result in excessive temperatures in the exhaust

system and on the floor pan.

Fig. 3 Front Floor Pan Heat Shield

EXHAUST GAS RECIRCULATION (EGR)

To assist in the control of oxides of nitrogen (NOx)

in engine exhaust, all engines are equipped with an

exhaust gas recirculation system. The use of exhaust

gas to dilute incoming air/fuel mixtures lowers peak

flame temperatures during combustion, thus limiting

the formation of NOx.

Exhaust gases are piped from the exhaust manifold

to the intake manifold through an EGR tube. Refer to

Group 25, Emission Control Systems for complete

description, diagnosis and service procedures of the

exhaust gas recirculation system and components.

Fig. 4 Rear Floor Pan Heat Shield

EXHAUST SYSTEM AND INTAKE MANIFOLD

11 - 3

EXHAUST SYSTEM DIAGNOSIS

11 - 4 EXHAUST SYSTEM AND INTAKE MANIFOLD

SERVICE PROCEDURES

INDEX

page

Catalytic Converter ....................... . 5

Exhaust Manifold—4.0L Engine ............... 6

Exhaust Manifold—5.2L Engine ............... 9

Exhaust Pipe ............................ . 4

Intake Manifold—4.0L Engine ................. 6

Intake Manifold—5.2L Engine ................. 7

Muffler and Tailpipe ....................... . 5

EXHAUST PIPE

WARNING: IF TORCHES ARE USED WHEN WORK-

ING ON THE EXHAUST SYSTEM, DO NOT ALLOW

THE FLAME NEAR THE FUEL LINES.

REMOVAL

(1) Raise and support the vehicle.

(2) Saturate the bolts and nuts with heat valve

lubricant. Allow 5 minutes for penetration.

(3) Remove the oxygen sensor from the exhaust

pipe (Fig. 1 or 2).

Fig. 2 Exhaust Pipe (5.2L Engine)

(b) While the metal is still cherry red, twist the

exhaust pipe back and forth to separate it from the

catalytic converter.

(6) Disconnect the exhaust pipe hanger from the

rear mount bracket insulator (Fig. 3).

(7) Remove the exhaust pipe.

Fig. 1 Exhaust Pipe (4.0L Engine)

INSTALLATION

(1) Position the exhaust pipe onto the catalytic con-

verter.

(2) Connect the exhaust pipe hanger to the rear

mount bracket insulator.

(3) On 4.0L engines, install a new seal between the

exhaust pipe and the engine exhaust manifold (Fig.

1). Connect the exhaust pipe to the engine exhaust

manifold. Tighten the nuts to 31 N

(4) Disconnect the exhaust pipe from the engine

exhaust manifold. On 4.0L engines, discard the ex-

haust manifold seal (Fig. 1).

(5) Remove the exhaust clamp and nuts from the

exhaust pipe and catalytic converter connection (Fig.

1 or 2). Disconnect the exhaust pipe from the catalytic

converter. If needed:

(a) Heat the exhaust pipe and catalytic converter

connection with an torch until the metal becomes

cherry red.

m (23 ft. lbs.)

torque.

(4) Position the exhaust clamp assembly over the

exhaust pipe/catalytic converter connection (Fig. 1 or

2). Tighten the nuts to 34 N

m (35 ft. lbs.) torque.

m (25 ft. lbs.) torque.

(5) Coat the oxygen sensor with anti-seize com-

pound. Install the sensor and tighten the nut to 48

EXHAUST SYSTEM AND INTAKE MANIFOLD

11 - 5

Fig. 3 Rear Mount Bracket Insulator

(6) Lower the vehicle.

(7) Start the engine and inspect for exhaust leaks

and exhaust system contact with the body panels.

Adjust the alignment, if needed.

(8) After initial start-up, check the engine exhaust

manifold to exhaust pipe nuts for proper torque.

Fig. 4 Exhaust Pipe-to-Catalytic Converter-to-Muffler

Connection

(3) Install the exhaust clamp assembly at the muf-

fler and catalytic converter connection (Fig. 4).

Tighten the clamp nuts to 34 N

CATALYTIC CONVERTER

(4) Lower the vehicle.

(5) Start the engine and inspect for exhaust leaks

and exhaust system contact with the body panels.

Adjust the alignment, if needed.

WARNING: IF TORCHES ARE USED WHEN WORK-

ING ON THE EXHAUST SYSTEM, DO NOT ALLOW

THE FLAME NEAR THE FUEL LINES.

MUFFLER AND TAILPIPE

All original equipment exhaust systems are manu-

factured with the tailpipe welded to a stamped muf-

fler. Service replacement mufflers and tailpipes are

either clamped together or welded together.

REMOVAL

(1) Raise and support the vehicle.

(2) Saturate the bolts and nuts with heat valve

lubricant. Allow 5 minutes for penetration.

(3) Remove the clamp and nuts from the catalytic

converter and exhaust pipe connection (Fig. 4).

(4) Remove the clamp and nuts from the catalytic

converter and muffler connection (Fig. 4).

(5) Heat the exhaust pipe, catalytic converter and

muffler connections with an torch until the metal

becomes cherry red.

(6) While the metal is still cherry red, twist the

catalytic converter back and forth to separate it from

the exhaust pipe and the muffler.

WARNING: IF TORCHES ARE USED WHEN WORK-

ING ON THE EXHAUST SYSTEM, DO NOT ALLOW

THE FLAME NEAR THE FUEL LINES.

REMOVAL

(1) Raise and support the vehicle.

(2) Saturate the bolts and nuts with heat valve

lubricant. Allow 5 minutes for penetration.

(3) Remove the exhaust clamp and nuts from the

catalytic converter and muffler connection (Fig. 4).

(4) Heat the catalytic converter-to-muffler connec-

tion with an torch until the metal becomes cherry red.

(5) While the metal is still cherry red, remove the

tail pipe/muffler assembly from the catalytic con-

verter.

(6) Remove the tailpipe from the tailpipe hanger

(Fig. 5).

(7) Remove the tailpipe/muffler assembly.

INSTALLATION

(1) Position the exhaust clamp assembly over the

exhaust pipe/catalytic converter connection (Fig. 4).

Tighten the nuts to 34 N

m (25 ft. lbs.) torque.

(2) Install the muffler onto the catalytic converter

until the alignment tab is inserted into the alignment

slot.

Plik z chomika:

Inne pliki z tego folderu:

Inne foldery tego chomika: