sure way to test cat?

[zedjr10]

I have a 92 accord ex coupe. I want to test to see if my catalytic converter is clogged. My o2 sensor is right before the cat. Is putting a pressure gauge here in the o2 sensor the definitive way to test a cat. If it goes above 4psi it is basically clogged. Right. I see manuals online so i can follow them. Seems simple enough but not sure if this is the for sure test. Can't muffler be clogged then also?

[F22Chris]

Test catalysts with a laser infrared temperature gun. Temps should be lower coming out of the catalyst than going in. In your case with the sulfur smell, the cat might show hotter coming out. Which means a rich condition, and it's working over time. There's also a way to check for blockage with a pressure gauge, but I don't know the numbers to give you.

[zedjr10]

Test catalysts with a laser infrared temperature gun. Temps should be lower coming out of the catalyst than going in. In your case with the sulfur smell, the cat might show hotter coming out. Which means a rich condition, and it's working over time. There's also a way to check for blockage with a pressure gauge, but I don't know the numbers to give you.

The temps coming in at idle on front bolts of cat were 270F-275F and going out on rear bolts it was 295F. This is stock cat and probably the originial.I tested this after idling it for 20 minutes. This is rich? I thought this meant normal. That the converter was doing its work. I am going to repeat this test at 2500 rpm's with someone stepping on gas and see what i get. This temp test doesn't see if it is clogged partially. Just if it is working. Going to try to find a store who rents back pressure gauges and test at my o2 sensor. Oreillys and Advance don't loan . The back pressure test is pretty simple. Anything above 4 psi will basically tell you if it is the cat or something behind it.

[edit] I watched a few videos on this and gotten a much better understanding now of how to use IR thermometer on testing the cat. Here are the top 2 i think explains it best. https://www.youtube.com/watch?v=psIFUZaLLaM and of course Eric the Car Guy https://www.youtube.com/watch?v=9VZ5K8n5jj0. I need to rev up my engine a bit to get it to "light off" temps which i don't think 270 is it. 2k rpms am sure will get it above 300 F. I'll report back tomorrow.

[zedjr10]

Tested the cat again with IR thermometer at 2k rpms.Cat Inlet read 368 F and outlet read 480 F. I think this is in normal operating conditions. Next I am going to test with a back pressure gauge to see if i have any blockage in my exhaust system.