Is this catalytic converter clogged?

trey3 · May 22, 2020

I have a 2000 Suburban with 340K miles original engine. I did just have a Jasper transmission installed. The past few years it has been getting kind of sluggish it seems. It kind of feels like the exhaust is clogged. I figured with that many miles the catalytic converter would have to be clogged since it does burn a bit of oil. Like a quart every 2000 miles, but it has done that for 12 years. I took out the upstream O2 sensor and inserted a little camera. It looks pretty good to me, but I haven't see one of these new or clogged. I would love to hear everyone's thoughts.

carnau · May 22, 2020

7 minutes ago, trey3 said:

I have a 2000 Suburban with 340K miles original engine. I did just have a Jasper transmission installed. The past few years it has been getting kind of sluggish it seems. It kind of feels like the exhaust is clogged. I figured with that many miles the catalytic converter would have to be clogged since it does burn a bit of oil. Like a quart every 2000 miles, but it has done that for 12 years. I took out the upstream O2 sensor and inserted a little camera. It looks pretty good to me, but I haven't see one of these new or clogged. I would love to hear everyone's thoughts.

Ok, it would be almost impossible to look at this picture and tell if it is clogged. With the upstream O2 Sensor out, Take it for a test drive and see if it feels like any power has returned.

That or buy an inexpensive back pressure gauge and test it the correct way.

Back Pressure gauge - https://amzn.to/2WTrADK

sefiroxx · May 22, 2020

Leave the upstream o2 sensors out for the rest drive

davester · May 23, 2020

It's unlikely you will have a good comparison of how the engine runs between running it with the upstream O2 sensors in vs with the upstream O2 sensors out, as the ECM runs the engine entirely differently (open loop mode vs closed loop), so you won't know if whatever difference you feel/hear is from the ECM running the engine differently, or from the realively small amount of exhaust being able to escape via the O2 sensor hole.

I would recommend doing the backpressure test. It's not that expensive, particularly compared with how expensive new cat's are (at least, new cat's that will last).

trey3 · May 23, 2020

I didn't realize there was such a tool. I just ordered it and it will be here tomorrow. I will report my findings.

Thanks Everyone!

swathdiver · May 23, 2020

The purpose of your downstream O2 sensors is to measure the health of your cats. If the O2 sensors are not throwing their own codes, they are good and doing their job. They can detect when the cats are failing or have failed and there are specific codes for that. Usually, our first indication that the cats are wearing out is reduced fuel economy, not performance.