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11 - 4
EXHAUST SYSTEM
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
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 and PEP
module. Select the available menu options on the
DRBIII 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 . 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
and PEP
3.45 Kpa (0.5 psi)
REMOVAL - EXHAUST SYSTEM
NOTE:
Some
service
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.
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) 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
to 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.
procedures
require
JR
the
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