Restricted Exhaust System Check

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 O2S 1 location. Once the test is completed, coat threads with anti-seize compound P/N 5613695 or equivalent prior to O2S re-installation.

Diagnostic Chart:

TEST DESCRIPTION
The numbers below refer to the step numbers on the diagnostic table:
3. The exhaust system under normal conditions has very low back pressure. If the exhaust system is restricted, a noticeable increase in exhaust pressure is noticed on the gauge.
4. If no high back pressure is found at idle, increasing the engine speed to 3,000 RPM may find a slight restriction. The added engine speed increases the exhaust flow which will help determine if there is a slight restriction.