Hey guys...been a long time. So I finally figured out what all the rattling noises are whenever I accelerate from idle. For years I thought it was my headers and/or possibly the exhaust resonator that I replaced with a straight pipe...but all this time it was my catalytic converter! I almost found out the hard way too when my car (2002 TLS) refused to go to redline and was producing a loud whisting noise!

I took it to a shop right away and after 2 visits, we determined it was the catalytic converter (verified by removing the cat and inspecting the inside. There's a big chunk of ceramic block that just goes back and forth the canister. Too big to pull out, but small enough to temporarily clog the hole, causing my check engine light to flash once.)

I was quoted $1150 for the parts and labor.

I recently passed smog (even with the clunky cat) and would like to stretch out my dollar as far as possible. So...My question to you guys is...

Can I simply remove my catalytic converter and gut the piece out? Or would doing so produce a check engine light permanently?

Recommendations welcome.

 

Yes you will have a check engine light.

You can buy the aftermarket replacement at your local Kragen Auto. They are CARB legal and they go for $256.99. It is universal so it will have to be welded in. Just take it to your local exhaust shop and they should install it for less than $50. Total cost should be around $320-330 after it's all done.

 

I think I've read about others having CEL issues after using non-OEM cat. Maybe research it more.

 

I have the same problem, passed smog no problem. My plan is to cut a hole large enough to get the piece that has broken off out, and seal it back.
If that works, I just save myself some $, if it does not work = no cost. Just keep on driving around without the rattling noise.

 

This doesnt make any sense. Wouldn't it be better to just unbolt the cat and "icepick" the guts out with a long screwdriver and mallet and bolt it back on? Why cut anything? Am I missing something?

 

Yes!! What you are missing is that it is a functioning cat. Except for a small chunck of the internals has broken off, it works fine. Cutting a hole on the casing to get the piece that is causing the rattling sound and seal it back, and still have a cat that does not trigger the cel and pass smog is all I am looking for.
Taking the complete internals out may/will compromise future smog test result.

 

As long as it's the correct one by application and it's installed correctly, you shouldn't have any issues. The ones that Kragen carries are made by Magnaflow, a well known exhaust company.

 

Well I ended up ordering a SS "Random Technology" CAT from exxelerate. Looking to have it delivered and installed hopefully by this weekend. Will report results.

 

Update: Results better than expected. For YEARS I had this resonance when I hit 2~3k rpm. I was 100% sure it was the headers, however now with the new CAT, the resonance is GONE! I haven't really driven it long enough to notice any sound difference, but then again I'm just so amazed how "quiet" the car seems now that the rattles are gone.

One thing to note was that the mechanics were a bit worried that the exhaust was spitting out blue smoke. However after some burn in time, that too seems to have gone away. Also, I looked at my old CAT and I think it can still work and not give out a check engine light after I gut the rattling piece out. It seems to be made into 2 sections and the piece thats loose is located AFTER the O2 sensor.

headers===>screen===>ceramic===>screen===>O2 sensor===>ceramic (this is the loose part)===>and maybe screen (don't know if the mechanic punched the last screen out or not)===>b-pipe

So although I probably didn't need a new CAT, I'm still happy that all the rattling is gone.

 

same issue. Emission failed. bad converter code.
ordering my from ebay store around $105 free ship universal magnaflow brand. dealer want around $850.00 for OEM cat. have to go with universal cause the one on the car is welded on. probably wrong application because it don't look any thing like oem.
Hope it fix the problem.

 

The universal ones are exactly that, universal. They will not look like the original but they are made to take the place of it. As long as the part number is intended for your car then it will work fine.