Do it yourself test for clogged cat?

Anyone out there know of a DIY test for a clogged cat?

yes get a non contact infra red thermometer and check the inlet vs outlet temps of the convertor should be at least 100-150 degrees difference.

ps, forgot outlet hotter.

I go by the age and performance of the car. If the cat is like 90k miles old and I have doubts about it, I'll change it.

Sometimes they will leak out the sides if they have a significant clog. Have someone place a rag over the exhaust while you listen by the cat. If it hisses out the seams, you have a clog.

Where I live, we have emissions testing on anything 25 years or younger. My '84 was flunking and I put a new cat on it last year. The emissions are great now and it has more low end power.

Bob

My car has no low end power at all....it just kinda bogs down, when the rpms start to get higher, it will start to pick up...then when the rpms get around 3.5 grand it will take right off. It doesn't have the get up and go like it use to. Passing gear use to be fricking awesome..but not anymore....
I wanna replace it but i just wanna make sure it's the problem because the cat so fucking expensive....

let me know
mike

Hehe...well I hate to bring this up...but as a firm do it yourselfer...i learned on my 84 IROC how to handle to cat problem do it yourself style if emissions aren't a problem... A good long flat head, and a solid hammer! ;-) Should take right care of things. But that will fail emissions if you still need to pass em. Also...I'm not sure how good that is for the newer vehicals that read off backpressure. Also it may trigger a check engine light for the car. So...check before you do this...

My car has no low end power at all....it just kinda bogs down, when the rpms start to get higher, it will start to pick up...then when the rpms get around 3.5 grand it will take right off. It doesn't have the get up and go like it use to. Passing gear use to be fricking awesome..but not anymore....
I wanna replace it but i just wanna make sure it's the problem because the cat so fucking expensive....

let me know
mike

I'm just popping in to say my 03 LS had a clogged cat at 40k miles. Warrenty covered replacement even :iceslolan But the car ran so so horrible before the repair. I think the semi's were beating me off the line :disappoin

My car has no low end power at all....it just kinda bogs down, when the rpms start to get higher, it will start to pick up...then when the rpms get around 3.5 grand it will take right off. It doesn't have the get up and go like it use to. Passing gear use to be fricking awesome..but not anymore....
I wanna replace it but i just wanna make sure it's the problem because the cat so fucking expensive....

let me know
mike
After reading this thread I checked the cat temperature with a millivolt rtd multimeter attachment . After starting the car cold I was able to track the temperature as the car warmed up. I found the FRONT of the cat to be 60 degrees(F) hotter then the rear. This would indicate clogging and the performance of the car was exactly as you describe.
I gave the cat a good beating with the round end of a ball peen hammer. The temperature stabilized and there is now only about 10 degrees difference front and back.
Took the car out for a test drive and was amazed at the difference in performance. It will actually bark those Goodyear RSA's from a stop and the mid range acceleration was excellent where before it felt like the torque convertor was locked in overdrive and you had to floor the accelerator to get any power.
The cat looks like a grenade went off under it but the car is usable and hopefully it will be ok until I can pick up a new (aftermarket) replacement.

Good work rtx, when you put the new cat on look for 50-100 degress difference, the outlet should be hotter, interesting test.

Making me wonder if anyone is running no-cat? I only say this for states like mine (Michigan) where we don't have emissions testing and whatnot. Its far easier to get away with no cat, though I imagine a difference in the sound of the car :-D

the converter is warranty for 8/80k i think, we see alot of plugged converters on the impalas with varying mileage, and i think the 3.8 cars have an updated brake booster vac. hose that is supposed to be used when the converter is replaced also.

the converter is warranty for 8/80k i think, we see alot of plugged converters on the impalas with varying mileage, and i think the 3.8 cars have an updated brake booster vac. hose that is supposed to be used when the converter is replaced also.

Interesting. . . I'm not surprised they get a lot of plugged ones. Though I don't think mines plugged up at all for the life of the car, which is strange. . .

Interesting. . . I'm not surprised they get a lot of plugged ones. Though I don't think mines plugged up at all for the life of the car, which is strange. . .

Just had the GM dealer install a new cat today to replace my clogged one. The bill was for $700.......cost to me ..$0!
That's right........0$. I followed up on another thread posted on this forum Re: extended coverage for the '01/'02 3.4 @ 3.8 litre engine cat convertors.
GM will analyse each case on its own merits and replace any clogged cats up to 190,000 km or 10 yrs old.
My Impala had 147,000 on it.
The car pulls hard now right from a stop with no hesitation or flat spots.
My thanks to Cory Soehner and all staff at Stedelbauer Chevrolet on Ottawa St. in Kitchener for their prompt and expert service.
I would highly recommend this dealer to anyone in the K-W area. They are in the midst of a $2 million expansion and it's a busy spot, but they got me in on short notice and I was on my way 2 hrs later.

sweet! it's funny you mention that extended coverage aspect, i just got a letter on it the other day. ironic part is, i work for a chevy dealer and the first i heard of the extended coverage was the letter i got :shakehead [ i have an '02 monte SS] great communication at work :screwy: .


anyway, glad you got it sorted out for no cash outlay :biggrin: