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DIAGNOSIS AND TESTING DIAGNOSIS AND TESTING - EXHAUST SYSTEM CONDITION POSSIBLE CAUSES CORRECTION EXCESSIVE EXHAUST 1. Exhaust manifold cracked or 1. Replace manifold. 2. Manifold to cylinder head leak. 2. Tighten manifold and/or replace gasket. 3. Exhaust Flex joint to manifold 3.Tighten fasteners or replace gasket. 4. Exhaust flex joint. 4. Replace catalytic converter assembly. 5. Pipe and shell noise from front 5. Characteristic of single wall pipes. EXCESSIVE EXHAUST 1. Leaks at pipe joints. 1. Tighten or replace clamps at leaking 2. Burned, blown, or rusted out 2. Replace muffler or exhaust pipes. 3. Restriction in muffler or tailpipe. 3. Perform exhaust system restriction 4. Catalytic converter material in 4. Replace muffler and converter assembly. DIAGNOSIS AND TESTING - EXHAUST SYSTEM 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- NOTE: For Special Tool identification, (Refer to 11 - (1) Disconnect and remove the upstream (before catalytic converter) oxygen sensor. (Refer to 14 - (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 t display screen for using the digital pressure gauge function. (5) Apply the park brake and start the engine. engine speed to 2000 RPM. Monitor the pressure t. Back pressure should not exceed specified limit. Refer to specification in table (7) If pressure exceeds maximum limits, inspect exhaust system for restricted component. For further 11 - 18 EXHAUST SYSTEM PL/SRT-4 EXHAUST SYSTEM (Continued) |