els consists of a front mounted catalytic converter,
resonator/pipe assembly, muffler/pipe assembly, band
clamps, and support isolators. The upstream oxygen
sensor is located in the exhaust manifold. The down-
stream oxygen sensor is located in the catalytic con-
verter.

The exhaust system on the 2.7L engine model con-

sists of front and rear bank catalytic converters,
cross-under

pipe,

connector

pipe,

resonator/pipe

assembly, muffler/pipe assembly, band clamps, and
support isolators. The upstream oxygen sensors are
located in the front and rear exhaust manifolds. The
downstream oxygen sensors are located in the cross-
under pipe.

Resonators, mufflers, and exhaust pipes are tuned

to each powertrain combination. (Fig. 1), (Fig. 2), and
(Fig. 3).

EXHAUST SYSTEM

11 - 1

Fig. 2 EXHAUST SYSTEM SUPPORTS

1 - GROUND STRAP
2 - RESONATOR GUIDANCE BRACKET

3 - MUFFLER/FRONT PIPE SUPPORT ISOLATOR
4 - REAR MUFFLER SUPPORT ISOLATORS

Fig. 1 EXHAUST SYSTEM

1 - FLEX JOINT
2 - BAND CLAMP
3 - RESONATOR ALIGNMENT PIN
4 - RESONATOR/PIPE ASSEMBLY
5 - BAND CLAMP
6 - MUFFLER/PIPE ASSEMBLY

7 - REAR MUFFLER SUPPORTS
8 - MIDPIPE SUPPORT
9 - OXYGEN SENSOR
10 - CATALYTIC CONVERTOR (2.0L/2.4L)
11 - CONNECTOR PIPE (2.7L)

11 - 2

EXHAUST SYSTEM

EXHAUST SYSTEM (Continued)

DIAGNOSIS AND TESTING

DIAGNOSIS AND TESTING - EXCESSIVE EXHAUST SYSTEM NOISE

CONDITION

POSSIBLE CAUSES

CORRECTION

EXCESSIVE EXHAUST NOISE

(UNDER HOOD)

1. Exhaust manifold cracked or
broken.

1. Replace manifold.

2. Manifold to cylinder head leak.

2. Tighten manifold and/or replace
gasket.

3. EGR Valve to manifold gasket
leakage.

3. Tighten fasteners or replace
gasket.

4. EGR Valve to EGR tube gasket
leakage.

4. Tighten fasteners or replace
gasket.

5. EGR tube to manifold tube
leakage.

5. Tighten tube nut.

6. Exhaust flex-joint to manifold
leak.

6. Tighten joint fasteners and/or
replace gasket.

7. Exhaust flex-joint.

7. Replace catalytic converter
assembly.

8. Pipe and shell noise from front
exhaust pipe.

8. Characteristic of single wall pipe.

EXCESSIVE EXHAUST NOISE

1. Leak at exhaust pipe joints.

1. Tighten clamps at leaking joints.

2. Burned or rusted out muffler
assembly or exhaust pipe.

2. Replace muffler resonator tailpipe
assembly or exhaust pipe with
catalytic converter assembly.

3. Burned or rusted out resonator.

3. Replace muffler resonator tailpipe
assembly.

4. Restriction in exhaust system.

4. Perform Exhaust System
Restriction Check. Replace
component as necessary.

5. Converter material in muffler.

5. Replace muffler and converter
assemblies. Check fuel injection and
ignition systems for proper
operation.

Fig. 3 Band Clamp

1 - CLAMP SIZE
2 - TORQUE SPECIFICATION

EXHAUST SYSTEM

11 - 3

EXHAUST SYSTEM (Continued)

DIAGNOSIS AND TESTING - EXHAUST SYSTEM
RESTRICTION CHECK

Exhaust system restriction can be checked by mea-

suring back pressure using the DRB III

t and PEP

module pressure tester.

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) Disconnect and remove the upstream (before

catalytic converter) oxygen sensor. (Refer to 14 -
FUEL SYSTEM/FUEL INJECTION/O2 SENSOR -
REMOVAL)

(2) Install the Exhaust Back Pressure Fitting

Adaptor CH8519.

(3) Connect the Low Pressure Sensor (15 psi)

CH7063 to the back pressure fitting.

(4) Following the PEP module instruction manual,

connect all required cables to the DRB III

t and PEP

module. Select the available menu options on the
DRBIII

t display screen for using the digital pressure

gauge function.

(5) Apply the park brake and start the engine.
(6) With transmission in Park or Neutral, raise

engine speed to 2000 RPM. Monitor the pressure
readings on the DRBIII

t. Back pressure should not

exceed specified limit. Refer to specification in table
below EXHAUST BACK PRESSURE LIMITS.

NOTE: For applications with dual catalytic convert-
ers, repeat test on opposite converter using the
previous steps.

(7) If pressure exceeds maximum limits, inspect

exhaust system for restricted component. For further
catalytic converter inspection procedures, (Refer to 11
- EXHAUST SYSTEM/CATALYTIC CONVERTER -
INSPECTION). Replace component(s) as necessary.

EXHAUST BACK PRESSURE LIMITS

Exhaust Back Pressure Limit (Max)

Vehicle in Park/Neutral

(no load) @2000 RPM

3.45 Kpa (0.5 psi)

REMOVAL - EXHAUST SYSTEM

NOTE:

Some

service

procedures

require

the

removal of the entire exhaust system in order to
gain better access to certain components for
removal and installation. The following procedure
explains how to remove the entire exhaust system.
Refer to specific procedures if replacing individual
exhaust components.

(1) Raise vehicle on hoist and apply penetrating oil

to fasteners that connect the exhaust system to the
exhaust manifold (2.0L/2.4L)/cross-under pipe (2.7L).

(2) Remove ground strap from muffler.
(3) Vehicles equipped with 2.0L/2.4L engines, dis-

connect downstream oxygen sensor connector.

(4) Remove fasteners that attach exhaust system

exhaust

manifold

(2.0L/2.4L)/cross-under

pipe

(2.7L).

CAUTION: Do not use any tools to remove the rub-
ber isolators—remove by hand only. Soapy water or
silicone-based lubricant spray may be used to
assist removal/installation of isolators. DO NOT use
a petroleum-based lubricant on the isolators, as
damage to the rubber material can occur.

(5) Remove support isolators from muffler supports

(Fig. 2).

(6) Remove exhaust system from vehicle.

NOTE: Band clamps are spot welded to exhaust
system. If a band clamp must be replaced, the spot
weld must be ground off the exhaust pipe.

NOTE: When replacement is required on any com-
ponent of the exhaust system, it is most important
that original equipment parts (or their equivalent)
be used for the following reasons:

• To insure proper alignment with other parts in

the system.

• Provide acceptable exhaust noise levels and does

not change exhaust system back pressure that could
affect emissions and performance.

11 - 4

EXHAUST SYSTEM

EXHAUST SYSTEM (Continued)

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