B Charts

Exhaust System Check:

CHECK AT HEATED OXYGEN SENSOR (HO2S):

1. Carefully remove heated oxygen sensor.
2. Install exhaust backpressure tester (BT-8515 or BT-8603) or equivalent in place of heated oxygen sensor (see illustration).
3. After completing test described below, be sure to coat threads of oxygen sensor with anti-seize compound P/N 5613695 or equivalent 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 should be suspected, and replaced using current recommended procedures.