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Discussion Starter · #1 ·
I punched my throttle a few weeks back getting out of an intersection. And ever since, the drivers cat sounds like a cement mixer at anything other than full throttle. I punched it again yesterday and it got worse. I know that it is the cat, but what is causing it. The car has 285k on it, and the cats have 150+k on them, but were in good shape 4 months ago when I installed them.
 

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What causes a cat to break up inside?
Age + miles + heat = brittleness = eventual breakage.

In other words, it ain't something that happened overnight......this has been building up since the car came off the factory line.

KW
 

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What causes a cat to break up inside?
Ninja Mouse?

Sorry, couldn't help myself.

KW is right. Things get old and wear out or break. GM designed them to make it 8 years or 80k miles. Anything more is gravy.
 

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Discussion Starter · #7 ·
Age + miles + heat = brittleness = eventual breakage.

In other words, it ain't something that happened overnight......this has been building up since the car came off the factory line.

KW
I know this. That is a given with anything.

If you have real lean exhaust and high exhaust temps you can burn them up.. QUICK.. When the car is rich it usally just clogges them up.
This is the kind of answer I was looking for. A lean condition is possible since the car has so many miles. I will change my injectors out with a known good low mile set I have, as I can only assume the the injectors might be clogged or close to clogged.
 

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Discussion Starter · #9 ·
From what I understand, a lean condition will cause your exhaust manifolds to heat up higher than normal, but a rich condition will cause your cats to heat up higher than normal.
The car has 285k on it with SLP shorty headers. What would cause a rich condition? I have a RAMIT system. Could this cause it to be rich since I have no tune to compensate?
 

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The car has 285k on it with SLP shorty headers. What would cause a rich condition? I have a RAMIT system. Could this cause it to be rich since I have no tune to compensate?
If anything that would cause a lean condition due to more air in the mixture, but Alex of PCM Performance assured me there is nothing to tune for with a CAI.

I'm really leaning towards age being the culprit here. 150k+ miles on these catalytic converters, how dare they break down...
 

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Discussion Starter · #12 · (Edited)
If anything that would cause a lean condition due to more air in the mixture, but Alex of PCM Performance assured me there is nothing to tune for with a CAI.

I'm really leaning towards age being the culprit here. 150k+ miles on these catalytic converters, how dare they break down...
I meant lean. But had rich on the mind.

And I do think maybe I have a lean condition, as I am moving more air with basicly the same amount of fuel, as the stock system may not be up to snuff and or the fuel system is just plain inadequit.
 
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