Table of Contents
Advertisement
CS
EXHAUST SYSTEM (Continued)
CONDITION
EXCESSIVE EXHAUST NOISE
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.
(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.
POSSIBLE CAUSES
1. Leak at exhaust pipe joints.
2. Burned or rusted out muffler
assembly or exhaust pipe.
3. Burned or rusted out resonator.
4. Restriction in exhaust system.
5. Converter material in muffler.
6. Substrate breakage in catalyltic
converter
NOTE: For applications with dual catalytic convert-
ers, repeat test on opposite converter using the
previous steps.
and PEP
(7) If pressure exceeds maximum limits, inspect
exhaust system for restricted component. Replace
component(s) as necessary.
Exhaust Back Pressure Limit (Max)
Vehicle in Park/Neutral
(no load) @2000 RPM
REMOVAL - EXHAUST SYSTEM
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.
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.
EXHAUST SYSTEM 11 - 3
CORRECTION
1. Tighten clamps at leaking joints.
2. Replace muffler resonator tailpipe
assembly or exhaust pipe with
catalytic converter assembly.
3. Replace muffler resonator tailpipe
assembly.
4. Perform Exhaust System
Restriction Check. Replace
component as necessary.
5. Replace muffler and converter
assemblies. Check fuel injection and
ignition systems for proper
operation.
6. Replace catalytic converter.
Check fuel injection system and
ignition system for proper operation.
Check manifold crossover pipe for
damage.
EXHAUST BACK PRESSURE LIMITS
3.45 Kpa (0.5 psi)
Advertisement
Table of Contents
