Restricted Exhaust System Check

Restricted Exhaust System Check

Diagnostic Chart (Part 1 Of 2):

Diagnostic Chart (Part 2 Of 2):

SYSTEM DESCRIPTION
Proper diagnosis for a restricted exhaust system is essential before any components are replaced. Using the Restricted Exhaust System Check table should determine if the exhaust system is restricted. The best place for testing the exhaust system is at the oxygen sensor (O2S 1) location. Once the test is completed, coat threads with anti-seize compound P/N 5613695 or equivalent prior to O2S re-installation.

TEST DESCRIPTION
The numbers below refer to the step numbers on the diagnostic table.
2. The exhaust system has very low back pressure under normal conditions. If the exhaust system is restricted, a significant increase in the exhaust pressure is noticed on the gauge.
3. If high back pressure is not found at idle, increasing the engine speed to 3,000 RPM may help find a slight restriction. The added engine speed will increases the exhaust flow.
4. This step will isolate the catalyst convertor from the remainder of the exhaust system.
6. If the muffler is plugged, inspect the catalytic convertor to determine if the internal material has broken apart.