Chrysler PT Cruiser 2001 Service Manual Supplement page 1061

11 - 4 EXHAUST SYSTEM
DIAGNOSIS AND TESTING
EXHAUST SYSTEM DIAGNOSIS
CONDITION
EXCESSIVE EXHAUST
NOISE (UNDER HOOD)
EXCESSIVE EXHAUST
NOISE
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 FUEL for
procedure.
(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) Start engine and monitor pressure readings.
POSSIBLE CAUSES
1. Exhaust manifold cracked or
broken.
2. Manifold to cylinder head leak.
3. Exhaust flex joint to manifold leak.
4. Exhaust flex joint.
5. Pipe and shell noise from front
exhaust pipe.
1. Leaks at pipe joints.
2. Burned, blown, or rusted out
exhaust pipe or muffler.
3. Restriction in muffler or tailpipe.
4. Catalytic converter material in
muffler.
and PEP
1. Replace manifold.
2. Tighten manifold and/or replace gasket.
3.Tighten fasteners or replace gasket.
4. Replace catalytic converter assembly.
5. Characteristic of single wall pipes.
1. Tighten or replace clamps at leaking
joints.
2. Replace muffler or exhaust pipes.
3. Remove restriction, if possible or replace
as necessary.
4. Replace muffler and converter assembly.
Check fuel injection and ignition systems for
proper operation.
(6) Raise engine speed to 2000 RPM. Back pres-
sure should not exceed specified limit. Refer to spec-
ification in table below.
(7) If pressure exceeds maximum limits, inspect
exhaust system for restricted component. Replace as
necessary.
Exhaust Back Pressure Limit (Max)
Vehicle in Park/Neutral
(no load) RPM
REMOVAL AND INSTALLATION
MUFFLER
REMOVAL
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 OPERATING TIME.
CORRECTION
3.45 Kpa (0.5 psi)
PT