19361226 Section 11 Exhaust System Ewj11

8/2/2019 19361226 Section 11 Exhaust System Ewj11

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EXHAUST SYSTEM

TABLE OF CONTENT S

page page

DESCRIPTION AND OPERATION

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

CATALYTICCONVERTER. . . . . . . . . . . . . . . . . . . . 3

HEAT SHIELDS . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

MUFFLER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

TAILPIPE. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

DIAGNOSIS AND TESTING

EXHAUST SYSTEM DIAGNOSIS. . . . . . . . . . . . . . 6

REMOVAL AND INSTALLATION

CATALYTICCONVERTER. . . . . . . . . . . . . . . . . . . 10

EXHAUST PIPE. . . . . . . . . . . . . . . . . . . . . . . . . . . 7

MUFFLER AND TAILPIPE. . . . . . . . . . . . . . . . . . 10

CLEANING AND INSPECTION

CATALYTIC CONVERTER. . . . . . . . . . . . . . . . . . . 11

EXHAUST PIPE. . . . . . . . . . . . . . . . . . . . . . . . . . 11

SPECIFICATIONS

TORQUE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

DESCRIPTION AND OPERATION

EXHAUST SYSTEM

DESCRIPTION

WARNING: THE NORMAL OPERATING TEMPERA-TURE OF THE EXHAUST SYSTEM IS VERY HIGH.THEREFORE, NEVER WORK AROUND OR ATTEMPTTO SERVICE ANY PART OF THE EXHAUST SYSTEM

UNTIL IT IS COOLED. SPECIAL CARE SHOULD BE

TAKEN WHEN WORKING NEAR THE CATALYTICCONVERTER. THE TEMPERATURE OF THE CON-VERTER RISES TO A HIGH LEVEL AFTER A SHORT

PERIOD OF ENGINE OPERATION TIME.

CAUTION: Avoid application of rust preventioncompounds or undercoating materials to exhaustsystem floor pan heat shields. Light overspray near

the edges is permitted. Application of coating willresult in excessive floor pan temperatures andobjectionable fumes.

T h e e x h a u s t s ys t e m u s e s a s in g le m u ffl er w it h a

welded tail pipe.

The 4.0L and 4.7L Federal Emissions vheicles use

a single catalytic converter, while the California mod-

els use two additional mini catalytic converters inline

with the exhaust pipe below the exhaust manifolds.

The 4.0L and 4.7L exhaust manifolds are equipped

w it h b a ll fla n ge ou t le t s t o a s su r e a t igh t s ea l a n d

strain free connections.

T h e e x h a u s t s ys t e m m u s t b e p r o pe r ly a l ig n ed t o

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

tem conta cts any body panel, i t may amplify objec-

tionable noises originating from the engine or body.

Wh e n in s p ect in g a n e xh a u s t s ys t em , cr it ica lly

inspect for cracked or loose joints, stripped screw or

bolt threads, corrosion damage and worn, cracked or

b r ok en h a n ge r s. R ep la ce a ll com p on e n t s t h a t a r e

b a dl y c or r od ed or d a m a ge d. D O N O T a t t e mp t t o

repair.

When replacement is r equired, u se original equip-

m e n t p a r t s (or t h e ir e qu i va l en t ). T h is w il l a s s u r e

p r op e r a l ig n m en t a n d p r ov id e a cce p t a bl e e xh a u s t

noise levels.

WJ EXHAUST SYSTEM 11 - 1


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The basic exhaust system consists of exhaust man-

ifold(s), exhaust pipe with oxygen sensors, cata lytic

converter(s), heat shield(s), muffler and tailpipe (Fig.

1) (Fig. 2).

Fig. 1 Exhaust System4.0L1 MINI CONVERTERS (2)

2 CATALYTIC CONVERTER

3 TAILPIPE HANGER REAR MOUNT INSULATOR

4 TAILPIPE

5 MUFFLER

6 OXYGEN SENSORS (FEDERAL)

7 OXYGEN SENSORS (CALIFORNIA ONLY)

11 - 2 EXHAUST SYSTEM WJ

DESCRIPTION AND OPERATION (Continued)


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CATALYTI C CONVERTER

DESCRIPTION

WARNING: THE NORMAL OPERATING TEMPERA-TURE OF THE EXHAUST SYSTEM IS VERY HIGH.

THEREFORE, NEVER WORK AROUND OR ATTEMPTTO SERVICE ANY PART OF THE EXHAUST SYSTEMUNTIL IT IS COOLED. SPECIAL CARE SHOULD BETAKEN WHEN WORKING NEAR THE CATALYTICCONVERTER. THE TEMPERATURE OF THE CON-VERTER RISES TO A HIGH LEVEL AFTER A SHORT


CAUTION: DO NOT remove spark plug wires fromplugs 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.

T h e s t a in le ss s t ee l ca t a ly tic con ve r t er b od y is

designed to last the life of the vehicle. Excessive heat

can result in bulging or other distortion, but exces-

s iv e h e a t w il l n o t b e t h e fa u l t of t h e con v er t e r. I f

unburned fuel enters the converter, overheating may

occu r . I f a con v er t e r i s h e a t -d a m a g ed , cor r e ct t h e

c a u s e o f t h e d a m a g e a t t h e s a m e t i m e t h e c o n v e r t e r

is replaced. Also, inspect all other components of the

exhaust system for heat damage.

U n l e a d e d g a s ol i n e m u s t b e u s e d t o a v o i d c o n -

t a m i n a t i n g t h e c a t a l y s t c o r e .

Fig. 2 Exhaust System4.7L1 CATALYTIC CONVERTER

2 EXHAUST PIPE

3 TAIL PIPE HANGER REAR MOUNT INSULATOR

4 TAILPIPE

5 MUFFLER




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Federal emission vehicles use only one cata lytic

converter, However, California emission vehicles

i n cor p or a t e t w o m i n i ca t a l yt i c con v er t e r s l oca t e d

after th e exhaust man ifolds and before t he inline cat-

alytic converter (Fig. 3) (Fig. 4).

Fig. 3 4.0L Catalytic Converter and O2 Sensor ConfigurationCalifornia and Federal Emissions




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MUFFLER

DESCRIPTION

B ot h t h e 4 .0 L a n d 4 .7 L e n g in e s u s e a s t a in l es s

s t e el m u ffl er t o con t r o l e x h a u s t n oi se l ev el s a n d

exhaust back pressure. The muffler and tailpipe are

a one piece assembly.

TAILPIPE

DESCRIPTION

The tailpipe is also made of stainless steel (Fig. 5).

OPERATION

The Tailpipe channels the exhaust out of the muf-

fler and out from under the vehicle to control noise

a n d p r ev en t e xh a u s t g as fu m e s fr om e n t er in g t h e

passenger compart ment

Fig. 4 4.7L Catalytic Converter and O2 Sensor ConfigurationCalifornia and Federal Emissions

Fig. 5 Muffler and Tailpipe Assembly1 CATALYTIC CONVERTER

2 TAILPIPE HANGER

3 TAILPIPE

4 MUFFLER




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HEAT SHIELDS

DESCRIPTION

Heat shields are needed to protect both the vehicle

a n d t h e e n vir on m e n t fr om t h e h ig h t e m pe r a t u r es

developed by the cata lytic converter. The cata lytic

con v er t e r r e le a s es a d d it i on a l h e a t i n t o t h e e xh a u s tsystem. Under severe operating conditions, the tem-

perature increases in the area of the converter. Such

conditions can exist when the engine misfires or oth-

erwise does not operate at peak efficiency (Fig. 6).

DIAGNOSIS AND TESTING

EXHAUST SYSTEM DIAGNOSISEXH A U ST SYSTEM D I A G N O SI S

CONDITION POSSIBLE CAUSE CORRECTION

EXCESSIVE EXHAUST NOISE 1. Leaks at pipe joints. 1. Tighten clamps at leaking joints.

2. Burned or blown out muffler. 2. Replace muffler assembly. Checkexhaust system.

3. Burned or rusted-out exhaustpipe.

3. Replace exhaust pipe.

4. Exhaust pipe leaking at manifoldflange.

4. Tighten connection attachingnuts.

5. Exhaust manifold cracked orbroken.

5. Replace exhaust manifold.

6. Leak between exhaust manifoldand cylinder head.

6. Tighten exhaust manifold tocylinder head stud nuts or bolts.

7. Restriction in muffler or tailpipe. 7. Remove restriction, if possible.Replace muffler or tailpipe, asnecessary.

8. Exhaust system contacting bodyor chassis.

8. Re-align exhaust system to clearsurrounding components.

LEAKING EXHAUST GASES 1. Leaks at pipe joints. 1. Tighten/replace clamps at leakingjoints.

2. Damaged or improperly installedgaskets (4.0L only).

2. Replace gaskets as necessary(4.0L only).

Fig. 6 Front and Rear Floor Pan Heat Shields1 REAR FLOOR PAN HEAT SHIELD

2 HEAT SHIELD RETAINING NUTS (QTY 8) TIGHTEN TO 2 Nm(20 IN. LBS.)

3 FRONT FLOOR PAN HEAT SHIELD




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REMOVAL AND INSTALLATION

EXHAUST PIPE

REMOVAL

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

WARNING: THE NORMAL OPERATING TEMPERA-

TURE OF THE EXHAUST SYSTEM IS VERY HIGH.THEREFORE, NEVER WORK AROUND OR ATTEMPTTO SERVICE ANY PART OF THE EXHAUST SYSTEMUNTIL IT IS COOLED. SPECIAL CARE SHOULD BE

TAKEN WHEN WORKING NEAR THE CATALYTICCONVERTER. THE TEMPERATURE OF THE CON-VERTER RISES TO A HIGH LEVEL AFTER A SHORT


(1) Raise and support the vehicle.

(2 ) Sa t u r a t e t h e b olt s a n d n u t s w it h h e a t v a lve

lubricant. Allow 5 minutes for penetration.

(3 ) R em ov e t h e ox yg en s e n sor fr om t h e e xh a u s t

pipe (Fig. 7) (Fig. 8).

(4 ) H e a t t h e e xh a u s t p ip e a n d ca t a l yt i c con v er t e r

con n e ct ion w it h a t or ch u n t il t h e m e t a l b ecom e scherry red. While the metal is st i l l cherry red, twist

the catalytic converter back and forth to separate i t

from the exhaust pipe (Fig. 9).

Fig. 7 O2 Sensor Location 4.0L



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(5) Disconnect t he exhau st pipe from t he exhaust

manifold. (Fig. 10) (Fig. 11).

(6 ) R em ov e t h e e xh a u s t cl a m p fr om t h e m u ffl er

and catalytic converter connection. Disconnect the

muffler from the catalytic converter. If needed:

(7) Disconnect t he tail pipe from the han ger (Fig.

12).

(8) Remove the muffler and tail pipe.

INSTALLATION

NOTE: When servicing the exhaust system, replace

the factory installed uni-clamp with standard u-boltclamps.

(1) If the catalytic converter was removed, Install

the catalytic converter onto the exhaust pipe (Fig. 9).

(2) Position the muffler and tail pipe onto th e cat-

alytic converter.

(3) Connect the tail pipe hanger to the rear mount

bracket insulator (Fig. 12).

Fig. 8 O2 Sensor Location 4.7L

Fig. 9 Catalytic ConverterRemoval1 EXHAUST PIPE



REMOVAL AND INSTALLATION (Continued)


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(4) Connect the exhau st pipe to the engine exhaust

m a n i fol d. T ig h t en t h e n u t s t o 3 1 N m (2 3 ft . l bs .)

(Fig. 10) (Fig. 11).

NOTE: When servicing the exhaust system, replacethe factory installed uni-clamp with standard u-bolt

clamps.

(5 ) P os it i on t h e e xh a u s t cl a m p ov er t h e e xh a u s t

pipe/catalytic converter connection. Tighten clamp

retaining nuts to 61 Nm (45 ft . lbs.) . (Fig. 13)

Fig. 10 Exhaust Pipe 4.0L1 EXHAUST HANGER

2 EXHAUST PIPE

Fig. 11 Exhaust Pipe 4.7L1 EXHAUST PIPE HANGER

2 EXHAUST PIPE

ITEM DESCRIPTION

A NUT Qty.4 Torque to 31Nm (23 ft. lbs.)

B BOLT Qty.4

Fig. 12 Muffler and Tail Pipe1 CATALYTIC CONVERTER

2 TAILPIPE HANGER

3 TAILPIPE

4 MUFFLER

Fig. 13 Installing Exhaust Clamps1 CATALYTIC CONVERTER

2 MUFFLER




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(6 ) C oa t t h e ox yg en s e n sor w it h a n t i -s e iz e com -

p o u n d . I n s t a l l t h e s e n s o r a n d t i g h t e n t h e n u t t o 4 8

Nm (35 ft. lbs.) torque (Fig. 8) (Fig. 7).

(7) Lower th e vehicle.

(8) Start the engine and inspect for exhaust leaks

a n d e xh a u s t s ys t e m con t a c t w it h t h e b od y p a n e l s.

Adjust the alignment, if needed.(9) After initial start-up, check the engine exhaust

manifold to exhaust pipe nuts for proper torque.

CATALYTIC CONVERTER

REMOVAL

WARNING: IF TORCHES ARE USED WHEN WORK-

ING ON THE EXHAUST SYSTEM, DO NOT ALLOWTHE FLAME NEAR THE FUEL LINES.


(2 ) Sa t u r a t e t h e b olt s a n d n u t s w it h h e a t va lv elubricant. Allow 5 minutes for penetration.

(3) Remove exhaust clamp from the cata lytic con-

verter and exhaust pipe connection (Fig. 14).

(4) Remove exhaust clamp from the cata lytic con-

verter and mu ffler connection (Fig. 14).

(5) Disconn ect oxygen sensor wiring (Fig. 14).

(6) Heat the exhaust pipe, catalytic converter and

m u ffle r con n e ct ion s w it h a t or ch u n t il t h e m e t a l

becomes cherry red.

(7 ) W h il e t h e m e t a l i s s t il l ch e r r y r e d , t w i st t h e

catalytic converter back and forth to separate it from

the exhaust pipe and the muffler (Fig. 15).

INSTALLATION

(1 ) P os it i on t h e e xh a u s t cl a m p ov er t h e e xh a u s t

pipe/catalytic converter conn ection (Fig. 14). Tighten

the nuts to 61 Nm (45 ft . lbs.) torque.

(2) Install t he muffler onto the catalytic converter

u n t il t h e a lign m e n t t a b is in s er t e d in t o t h e a li gn -

ment slot.

(3 ) I n s t a ll t h e e xh a u s t cl a m p a t t h e m u ffl er a n d

catalytic converter connection (Fig. 14). Tight en th eclamp nuts to 47 Nm (35 ft . lbs.) torque.

(4) Connect oxygen sensor wiring (Fig. 14).

(5) Lower the vehicle.



Adjust the alignment, if needed.

MUFFLER AND TAILPIPE

REMOVAL

All original equipment exhaust systems are manu-

factured with the tailpipe welded to th e muffler. Ser-

v ice r e p la ce m en t m u ffl er s a n d t a i lp ip e s a r e e it h e rclamped together or welded together.

WARNING: IF TORCHES ARE USED WHEN WORK-ING ON THE EXHAUST SYSTEM, DO NOT ALLOW

THE FLAME NEAR THE FUEL LINES.


(2 ) Sa t u r a t e t h e b olt s a n d n u t s w it h h e a t v a lve

lubricant. Allow 5 minutes for penetration.

(3 ) R e m ov e t h e e xh a u s t cl a m p fr om t h e ca t a l yt i c

converter and muffler connection (Fig. 16).

Fig. 14 Exhaust Pipe-to-Catalytic Converter-to-Muffler Connection

1 EXHAUST CLAMP ASSEMBLY

2 OXYGEN SENSOR

3 MUFFLER


5 EXHAUST PIPE

Fig. 15 Catalytic ConverterRemoval1 EXHAUST PIPE





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(4) Heat th e catalytic converter-to-muffler connec-

tion with a torch until the metal becomes cherry red.

(5) While the metal is st i l l cherry red, remove the

t a i lp ip e /m u ffl er a s s em b ly fr om t h e ca t a l yt i c con -

verter.

(6) Remove th e tailpipe from the tailpipe hanger

(Fig. 17).

(7) Remove the ta ilpipe/muffler assembly (Fig. 17).

INSTALLATION

(1 ) I f t h e t a i lp ip e h a n g e r a s s em b ly w a s r e m ov ed ,

i n s t a l l t h e h a n g e r t o t h e f r a m e . T i g h t e n t h e b o l t s t o

22 Nm (192 in. lbs.) torque.

(2 ) P os it ion t h e t a ilp ip e a n d m u ffle r on t o t h e

tailpipe hanger (Fig. 17).

(3) Insta ll the m uffler onto the catalytic convert er.Make sure that the tailpipe has sufficient clearance

from th e floor pan. In stall exhaust clamp a nd t ighten

the nuts to 47 Nm (35 ft . lbs.) torque (Fig. 16).

(4) Lower the vehicle.



Adjust the alignment, if needed.

CLEANING AND INSPECTION

EXHAUST PIPE

CLEANING

Clean ends of pipes to assure mating of all parts.

INSPECTION

D is ca r d r u s t e d cl a m ps , b r ok e n or w or n s u p p or t s

and attaching parts. Replace a component with orig-

inal equipment parts, or equivalent. This will assure

proper alignment with other parts in the system and

provide a cceptable exha ust noise levels.

CATALYTI C CONVERTER

CLEANINGC le a n e n d s o f p ip e s a n d m u ffl er t o a s s u r e a g ood

seal at mating surfaces.

INSPECTION

Look at the stainless steel body of the converter,

inspect for bulging or other distortion that could be a

r e su lt of ove r h ea t in g . I f t h e con v er t e r h a s a h e a t

shield attached make sure i t 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.

Fig. 16 Exhaust Pipe-to-Muffler Clamp1 CATALYTIC CONVERTER

2 MUFFLER

Fig. 17 Muffler and TailPipe Assembly1 CATALYTIC CONVERTER

2 TAILPIPE HANGER

3 TAILPIPE

4 MUFFLER




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SPECIFICATIONS

TORQUE

DESCRIPTION Nm Ft. In.

Lbs. Lbs.

Catalytic Converter-to-Exhaust Pipe

U-bolt rod clamp 61 45

Exhaust Pipe-to-ManifoldNuts

31 23

Floor Pan Heat ShieldBolts/Nuts

2.5 20

Muffler-to-CatalyticConverter

U-bolt rod clamp 47 35

Rear Tailpipe HangerBolts

22 192


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19361226 Section 11 Exhaust System Ewj11