Catalytic Converter Functional Test

NOTE: If all other emission systems are functioning correctly, but vehicle still has excessive tailpipe emissions, the catalytic converter core may by contaminated. To check converter effectiveness, perform the following test:

FUNCTIONAL CHECK
1. Warm the engine to normal operating temperature.
2. Run the engine at 2500 RPM for 30 seconds.
3. Using a pyrometer, measure the exhaust pipe temperature before and after the catalytic converter.
4. Exhaust pipe temperature should be at least 100° F hotter at the converter outlet than at the inlet.
5. If catalytic converter has little or no effect on exhaust temperature, the core may be contaminated.

NOTE: If exhaust temperature exceeds 450° F, the engine may be running too lean. Repair the lean running condition and recheck exhaust temperature before condemning the catalytic converter.