Three-Way Catalytic Converter

CATALYTIC CONVERTER INSPECTION

1. Visually inspect exterior of converter. If severe damage is noted, such a dented, crushed or rusted out shell, replace converter.
2. Whenever converter is removed from vehicle, check ceramic element through exhaust inlet and outlet. If element is clogged, melted or otherwise damaged, replace converter.

Restricted Exhaust System Check At Air Manifold:

RESTRICTED EXHAUST SYSTEM CHECK AT AIR INJECTION MANIFOLD

1. Remove check valve from air injection manifold.
2. Connect a fuel pressure gauge to a suitable hose and nipple.
3. Insert nipple into air injection manifold check valve opening.
4. With engine idling at normal operating temperature, the gauge reading should not exceed 8.6 kPa (1.25 psi).
5. Increase engine speed to 2000 rpm. Gauge reading should not exceed 20.7 kPa (3 psi).
6. If backpressure at either speed exceeds specification, a restricted exhaust system is indicated.
7. Inspect exhaust system for a collapsed pipe, heat distress or possible internal muffler failure.
8. If no obvious reasons for excessive exhaust system backpressure are found, suspect a restricted catalytic converter.

Exhaust System Back Pressure Check (Using Oxygen Sensor Mounting Hole):

RESTRICTED EXHAUST SYSTEM CHECK AT OXYGEN SENSOR

1. Remove oxygen sensor.
2. In place of the sensor, install a Borroughs exhaust backpressure tester (BT8515 or BT8603) or equivalent
3. With engine idling at normal operating temperature, the gauge reading should not exceed 8.6 kPa (1.25 psi).
4. Increase engine speed to 2000 rpm. Gauge reading should not exceed 20.7 kPa (3 psi).
5. If backpressure at either speed exceeds specification, a restricted exhaust system is indicated.
6. Inspect exhaust system for a collapsed pipe, heat distress or possible internal muffler failure.
7. If no obvious reasons for excessive exhaust system backpressure are found, suspect a restricted catalytic converter.
8. After completing test, coat threads of oxygen sensor with anti-seize compound prior to reinstallation.