Part of Lesson Plan: **Catalytic Converter (updated) by Richard Williams

Activity Overview / Details

Note: for this activity I have a video camera set up with large monitors for students to observe. The vehicle is also placed on an automotive lift for access.

First I discuss the pre-checks needed before a cat test can be run, some of them being cooling system operation and basic acceptable engine function. I then demonstrate the "2 & 2" (2 minutes at 2500 rpm) method of warming up a vehicle's catalytic converter. I also caution the students that this is a minimum requirement and that a good catalytic converter may take up to five minutes to reach a "light off" temperature. I demonstrate the acceptable methods for properly testing the catalytic converter for efficiency, while wearing my safety glasses and explaining safety items to be aware of when working with catalytic converter systems.

Methods to be used:

1.   Tap test
2.   Temperature difference
3.   Engine off CO2/HC
4.   Scan tool (OBD II vehicles)
5.   Engine running intrusive test
6.   Vacuum/back pressure