How to check for a plugged catalytic converter
If you suspect you’ve got a clogged catalytic converter, here’s how to do a plugged catalytic converter test.
But or rent an inexpensive vacuum gauge from any auto parts store. Connect the rubber hose from the gauge to any port on the intake manifold. Then,
1) Run the engine at idle. The vacuum reading should remain steady and within specifications. If vacuum drops toward zero, that in an indication of a plugged catalytic converter.
2. Slowly increase engine speed to 2,000 rpm. The vacuum reading should remain as high as at idle.
3. Quickly close the throttle. The vacuum reading should rise rapidly to above idle level. If the reading is 5 inHg or more below normal, and then returns slowly and unevenly, that’s a good indication of a plugged catalytic converter.
Posted on by Rick Muscoplat