EXJ_1199 jeep xj service manual

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EXHAUST SYSTEM

CONTENTS

page page

GENERAL INFORMATION

CATALYTIC CONVERTER . . . . . . . . . . . . . . . . . . . 1

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

DIAGNOSIS AND TESTING

EXHAUST SYSTEM . . . . . . . . . . . . . . . . . . . . . . . 2

REMOVAL AND INSTALLATION

CATALYTIC CONVERTER . . . . . . . . . . . . . . . . . . . 3

EXHAUST PIPE . . . . . . . . . . . . . . . . . . . . . . . . . . 2

MUFFLER AND EXHAUST TAILPIPE . . . . . . . . . . 4

SPECIFICATIONS

TORQUE SPECIFICATIONS . . . . . . . . . . . . . . . . . 5

GENERAL INFORMATION

EXHAUST SYSTEMTh e b a s ic e xh a u s t s y st e m con s is t s of a n e ng in e

exha ust man ifold, exhaust pipe w ith oxygen sensor,

ca t a l y t i c c on v er t e r w i t h ox y ge n s en s or, m u f fl er a n d

exha ust ta i lpipe (Fig. 1).

Th e e x ha u s t s y s t em u s es a s i n gl e m u f fl er w i t h a ca t -

alyt ic converter consist ing of dual ceramic monoliths.

Th e 4.0L e n gi n es u s e a s ea l bet w e e n t h e e n gi n e

e x h a u s t m a n i f o l d a n d e x h a u s t p i p e t o a s s u r e a t i g h t

seal and strain free connections.Th e e xh a u s t s y s t em m u s t be p r op er l y a l i g n ed t o

p r e v e n t s t r e s s , l e a k a g e a n d bo d y c o n t a c t . I f t h e s y s -

t e m con t a ct s a n y bod y p a n e l, i t m a y a m p l if y obje c-

tionable noises originating from the engine or body.

Wh en i n sp ect i n g a n e xh a u s t s y st e m, cr i t ica l l y

inspect for cracked or loose joints, stripped screw or

bolt threads, corrosion damage and worn, cracked or

b r ok en h a n g er s . R ep la c e a l l com pon en t s t h a t a r e

b a d ly cor r od ed or d a m a g ed . D O N OT a t t e m pt t o

repair.

When replacement is required, use original equip-

m en t p a r t s (or t h e ir e q ui va l en t ). Th i s w i l l a s s u re

p r op er a l i g n m en t a n d p r ov id e a c ce pt a bl e e xh a u s tnoise levels.

CAUTION: Avoid application of rust prevention

compounds or undercoating materials to exhaustsystem floor pan exhaust heat shields. Light overspray near the edges is permitted. Application ofcoating will result in excessive floor pan tempera-

tures and objectionable fumes.

CATALYTIC CONVERTERTh e s t a i n le ss s t eel ca t a l y t ic con v er t er b od y i s

designed t o last the l i fe of th e vehicle. Excessive heatca n r e su l t i n bu lg i n g or ot h e r d i st o r t ion , bu t e xce s-

s iv e h e a t w i ll n ot b e t h e f a u lt 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 e d, 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 al l other components of th e

e x h a u s t s y s t e m f o r h e a t d a m a g e .

U n l e a d e d g a s ol in e m u s t be u s e d t o a v oi d con 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. 1 Exhaust System2.5L/4.0L

XJ EXHAUST SYSTEM 11 - 1


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DIAGNOSIS AND TESTING

EXHAUST SYSTEMEXHAUST SYSTEM DIAGNOSIS CHART

CONDITION POSSIBLE CAUSE CORRECTIONEXCESSIVE EXHAUST NOISE ORLEAKING EXHAUST GASES

1. Leaks at pipe joints. 1. Tighten clamps/bolts at leakingjoints.

2. Rusted or blown out muffler. 2. Replace muffler. Inspect exhaustsystem.

3. Broken or rusted out exhaustpipe.

3. Replace exhaust pipe.

4. Exhaust pipe leaking at manifoldflange.

4. Tighten/replace flange attachingnuts/bolts.

5. Exhaust manifold cracked or

broken.

5. Replace exhaust manifold.

6. Leak between exhaust manifoldand cylinder head.

6. Tighten exhaust manifold tocylinder head bolts.

7. Catalytic converter rusted orblown out.

7. Replace catalytic converter assy.

8. Restriction in exhaust system. 8. Remove restriction, if possible.Replace restricted part if necessary.

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.

REMOVAL AND INSTALLATION

EXHAUST PIPE

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

CAUTION: When servicing exhaust system compo-

nents, disconnect the oxygen sensor connector.Allowing the exhaust system to hang by the oxygensensor harness will damage the wiring and/or sen-sor.

REM OVAL

(1) Raise and support the vehicle.

(2) S a t u r a t e t h e b ol ts a n d n u t s w i t h h ea t v a lv e

lubricant (Fig. 2). Allow 5 minut es for penetra tion.

(3) Disconnect the oxygen sensor connector (Fig.

3).

(4) D i s con n e ct t h e e xh a u s t p ip e f r om t h e e n gi n e

e xh a u s t m a n i fol d. D i s ca r d t h e s ea l (4. 0L e ng in e,

only).

(5 ) Su p p o r t t h e t r a n s m i s s i o n a n d r e m o v e t h e r e a r

crossmember.

(6) Remove th e clamp nuts an d clamp (Fig. 2). To

remove the exha ust pipe from t he cat alyt ic converter,

a p p l y h e a t u n t i l t h e m e t a l be c o m e s c h e r r y r e d . Di s -connect the exhaust pipe from the catalytic converter

(Fig. 2). Remove the exhaust pipe.

INSTALLATION

(1) As s em ble e xh a u s t p ip e t o m a n i f ol d a n d ca t a -

lytic converter loosely to permit proper al ignment of

a l l p a r t s .

(2) U s e a n ew cl a mp a n d t i gh t en t h e n u t s t o 6 1

Nm (45 ft . lbs.) torque.

(3) Connect the exhaust pipe to th e engine exha ust

m a n i fol d. I n s t a l l a n ew s ea l b et w e en t h e e x h a u st

m a n i f ol d a n d t h e e xh a u s t p ip e (4.0L e n gi n e on l y ).

Tighten the nuts to 31 Nm (23 ft . lbs.) torque (Fig.

2).

(4) I n st a l l t h e r ea r cr os sm em ber. I n st a l l a n d

tighten the four (4) crossmember to rear mount nuts

t o 2 2 N m (1 6 f t . l bs .) I n s t a l l a n d t i g h t e n t h e c r o s s -

m e m be r t o s i ll bol t s t o 42 N m (31 f t . l bs.) t o r q u e.

Remove the support from the transmission.

(5) C o a t t h e ox y g en s en s or w i t h a n t i -s ei z e c om -

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 2 7


(6) Lower the vehicle.

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(7 ) St a r t t h e e n g i n e a n d i n s p e c t f o r e x h a u s t l e a k s

a n d e xh a u s t s y st e m c on t a c t w i t h t h e b od y p a n el s.

Adjust the al ignment, i f needed.

CATALYTI C CONVERTER

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.

Allowing the exhaust system to hang by the oxygensensor harness will damage the wiring and/or sen-sor.

REMOVAL


(2) Remove the clamps from the cata lytic converter

and muffler connection (Fig. 4).

(3) Disconnect and remove the oxygen sensor from

the catalytic converter.

(4) H e a t t h e ca t a l y t i c con v er t e r a n d m u f fl er con -

n e ct i on w i t h a n ox y a ce t y le n e t o r ch u n t i l t h e m e t a l

becomes cherry red.

(5) Wh i le t h e m et a l i s s t il l c h er r y r ed , t w i s t t h e

m u f f l e r a s s e m bl y ba c k a n d f o r t h t o s e p a r a t e i t f r o m

the catalytic converter.

(6) Disconnect the exhaust pipe from the catalytic

converter (Fig. 4). If needed, heat up the pipes to sep-

a r a t e .

INSTALLATION

(1) Connect the catalytic converter to the exhaust

pipe and the muffler/ta ilpipe a ssy. (Fig. 4). U se a new

c l a m p a n d t i g h t e n t h e n u t s t o 6 1 N m ( 4 5 f t . l b s . )

torque.

(2) Instal l the muffler onto the catalytic converter

u n t il t h e a l i gn m en t t a b i s i n s er t ed i n t o t h e a l ig n -

ment slot .

Fig. 2 Exhaust Pipe Removal2.5L/4.0L

Fig. 3 Oxygen Sensor Location2.5L/4.0L


REMOVAL AND INSTALLATION (Continued)


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(3) I n s t a l l a n ew cl a m p a t t h e m u f fl er a n d ca t a -

lytic converter connection (Fig. 4). Tighten the clamp

nut to 61 Nm (45 ft . lbs.) torque.

(4) C oa t t h e ox y ge n s en s or w i t h a n t i -s ei z e c om -

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 2 7




a n d e xh a u s t s y st e m c on t a c t w i t h t h e b od y p a n el s.Adjust the al ignment, i f needed.

MUFFLER AND EXHAUST TAILPIPEAll original equipment exhaust systems are manu-

factured with the exhaust tai lpipe welded to the muf-

f ler. S er vi ce r epl a cem en t m u ff ler s a n d exh a u st

t a i l pi pes a r e e it h er cl a m pe d t og et h er or w e ld ed

together.

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

THE FLAME NEAR THE FUEL LINE.

CAUTION: When servicing exhaust system compo-nents, disconnect the oxygen sensor connector.

Allowing the exhaust system to hang by the oxygen

sensor harness will damage the wiring and/or sensor.

REM OVAL


(2) Disconnect front tai lpipe hanger from the insu-

lator (Fig. 5).

(3 ) R e m o v e t h e f r o n t e x h a u s t c l a m p f r o m t h e c a t -

alytic converter and muffler connection (Fig. 6).

(4) Hea t the cat aly tic converter-to-muffler connec-

t ion w i t h a n ox ya cet y len e t or ch u n ti l t h e m et a lbecomes cherry red.

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

exha ust muffler/ta ilpipe assembly from the cata lytic

converter.

(6) S l id e t h e m u f fl er /t a i lp ip e a s s y. r e a r w a r d a n d

ou t of t h e r ea r e xh a u s t t a i l pi pe m ou n t in g b r a ck et

(Fig. 7).

(7) Remove the muffler from the exhaust tai lpipe:

To remove a n original equipment exha ust muf-

f le r /t a i l p ip e com bin a t i on , cu t t h e e xh a u s t t a i l p ip e

Fig. 4 Catalytic Converter to Muffler and ExhaustPipe Connection

Fig. 5 Front Exhaust Tailpipe Hanger

Fig. 6 Catalytic Converter to Muffler Connection

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cl os e t o t h e m u f fl er. C o ll a p s e t h e p a r t r e m a i n in g i n

the muffler and remove.

To remove a service exha ust ta i lpipe/muffler

com b in a t i on , a p pl y h ea t u n t il t h e m et a l b ecom es

ch e r r y r e d. R e mov e t h e e xh a u s t t a i l p ip e/m u f fl er

c l a m p a n d t w i s t t h e e x h a u s t t a i l p i p e o u t o f t h e m u f -

fler.

INSTALLATION

(1) Instal l the muffler onto the catalytic converter.

I n s t a l l t h e c l a m p a n d t i g h t e n t h e n u t f i n g e r t i g h t .

(2) I n s t a l l t h e e xh a u s t t a i l p ip e i n t o t h e r e a r of t h e

muffler.

(3) Insta l l the exhaust ta i lpipe/muffler assembly

on the rear exhaust tai lpipe mounting bracket. Make

s u re t h a t t h e e xh a u s t t a i l pi pe h a s s u ff ici en t cl ea r -

ance from the floor pan.

(4 ) I n s t a l l f r o n t t a i l p i p e h a n g e r i n t o t h e i n s u l a t o r

(Fig. 5).

(5 ) A l i g n t h e m u f f l e r a n d t i g h t e n t h e n u t s o n t h e

muffler-to-catalytic converter clamp to 61 Nm (45 ft.

lbs.) torque (Fig. 6).

(6) Al ig n t h e t a i lp ip e a n d i n st a l l a n ew cl a m p a t

the muffler to ta i lpipe connection.

(7) Tighten the m uffler to t a ilpipe clamp t o 61 Nm

(45 ft. lbs.)



a n d e xh a u s t s y st e m con t a c t w i t h t h e b od y p a n el s.Adjust the al ignment, i f needed.

SPECIFICATIONS

TORQUE SPECIFICATIONS

Description Torque

Catalytic Converter/Exhaust Pipe

Exhaust Clamp Nut . . . . . . . . . . 61 Nm (45 ft . lbs.)

Crossmember to Sill

Bolts . . . . . . . . . . . . . . . . . . . . . . 42 Nm (31 ft . lbs.)

Crossmember to Transmission MountNu t s . . . . . . . . . . . . . . . . . . . . . . 22 N m (16 f t . l bs.)

Exhaust Pipe to Manifold

Nu t s . . . . . . . . . . . . . . . . . . . . . . 31 N m (23 f t . l bs.)

Exhaust Manifold2.5L Engine

Bolt #1 . . . . . . . . . . . . . . . . . . . . 41 Nm (30 ft . lbs.)


Nuts #6&7 . . . . . . . . . . . . . . . . . 31 Nm (23 ft . lbs.)


Nuts #6&7 . . . . . . . . . . . . . . . . . 31 Nm (23 ft . lbs.)

Bolt #3 . . . . . . . . . . . . . . . . . . . . 33 Nm (24 ft . lbs.)

Intake Manifold2.5L Engine

B olt #25 . . . . . . . . . . . . . . . . . . 31 Nm (23 ft . lbs.)Intake & Exhaust Manifold2.5L Engine

B olts #25 . . . . . . . . . . . . . . . . . 31 Nm (23 ft . lbs.)

Intake & Exhaust Manifold4.0L Engine

Nut s/B olts #1,2,4,5,811 . . . . . . . 33 Nm (24 ft. lbs.)

Muffler to Catalytic Converter

E x h a u s t C l a m p Nu t . . . . . . . . . . 61 N m (45 f t . l bs.)

Oxygen Sensors

Nut . . . . . . . . . . . . . . . . . . . . . . . 27 Nm (20 ft . lbs.)

Rear Tail Pipe Hanger

Nu t s . . . . . . . . . . . . . . . . . . . . . . 54 N m (40 f t . l bs.)

Fig. 7 Rear Exhaust Tailpipe Mounting Bracket




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EXJ_1199 jeep xj service manual

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