Chart B-1, Restricted Exhaust System Check

Fig 1: Chart B-1, Restricted Exhaust System Check

Before any components are replaced, exhaust system must be checked for restrictions. Check at O2 sensor procedure may be used to diagnose condition.

1. Raise engine speed to 2500 RPM and observe exhaust system backpressure gauge. Reading should not exceed 1.25 psi (.09 kg/cm² ).
2. If during step 1)  , specification is exceeded, exhaust system restriction is indicated.
3. Check complete exhaust system for collapsed pipe, heat distress and possible internal muffler failure.
4. If none of the conditions in step 4)  exist, check for restricted catalytic converter. Replace if necessary.