Exhaust System: Testing and Inspection

Back Pressure Test:

Proper diagnosis for a restricted exhaust system is essential before any components are replaced. The following procedure may be used for diagnosis:

CHECK AT 02 SENSOR:

1. Carefully remove O2 sensor.

2. Install Exhaust Backpressure Tester in place of 02 sensor.

3. After completing test described below, be sure to coat threads of O2 sensor with anti-seize compound prior to re-installation.

DIAGNOSIS:

1. With the engine at normal operating temperature and running at 2500 rpm, observe the exhaust system backpressure reading on the gauge.
2. If the backpressure exceeds 1 1/4 psi (8.62 kPa), a restricted exhaust system is indicated.
3. Inspect the entire exhaust system for a collapsed pipe, heat distress, or possible internal muffler failure.
4. If there are no obvious reasons for the excessive backpressure, a restricted catalytic converter is the most probable cause. Replace the converter.