verter, muffler, and a resonator with connecting pipes
in-between. The system is serviced in three sections;
the catalytic converter , the muffler, and the resona-
tor and tailpipe (Fig. 1). A torca clamp is used to con-
nect the joint between the muffler and catalytic

converter. A torca clamp is used to connect the muf-
fler and the resonator and tailpipe. Support hanger
rods with rubber isolators are used to support and
isolate the exhaust system. A flexible joint, integral
to the catalytic converter, allows for engine move-
ment. A second flexible joint is located between the
muffler and the resonator/tailpipe assemble to allow
for exhaust system movement. The exhaust system is
tuned for each vehicle/powertrain combination.

EXHAUST SYSTEM

11 - 1

Fig. 1 EXHAUST SYSTEM - TYPICAL (ALL)

1 - CATYLITIC CONVERTER
2 - TORCA CLAMP
3 - MUFFLER

4 - ISOLATOR
5 - RESONATOR/TAILPIPE

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 down pipe 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.

6. Substrate breakage in catalyltic
converter

6. Replace catalytic converter.
Check fuel injection system and
ignition system for proper operation.
Check manifold crossover pipe for
damage.

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.

(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. 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

VERTER RISES TO A HIGH LEVEL AFTER A SHORT
PERIOD OF ENGINE OPERATION TIME.

It is easier to service the exhaust system compo-

nents (Fig. 1) when system is removed from the vehi-
cle.

(1) Raise vehicle on hoist.
(2) Disconnect the two oxygen sensor connectors.
(3) Remove the nuts at the exhaust maifold.

CAUTION: At this time, the exhaust system is held
by only isolators. Support the exhaust system
underneath the front resonator and the muffler
while the isolators are being removed. Do not use
any tools to remove the isolators, remove by hand
only. Soapy water or silicone-based spray may be
used to assist removal. Do Not use a petroleum-
based lubricant on the isolators. This will damage
the rubber material.

(4) Support exhaust system with jack stand.
(5) Remove the rubber isolators from the support

brackets (Fig. 2).

(6) Lower exhaust system and lay on the ground.

NOTE: Care must be taken not to scratch the black
paint on the rear of the muffler (Fig. 2).

Fig. 2 Rubber Isolator Hanger to Body Support

Bracket

1 - SUPPORT BRACKET
2 - ISOLATOR
3 - RESONATOR/PIPE

11 - 4

EXHAUST SYSTEM

EXHAUST SYSTEM (Continued)

Content .. 711 712 713 714 ..