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clogged cats


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#1 ken1mod

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Posted 03 April 2006 - 08:24 PM

Gentlemen,

How common are clogged cat converters. I had one clog on a MotorHome once and it was an interesting experience. I am concerned about mine.

Ken

#2 mmmikkke

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Posted 04 April 2006 - 03:13 PM

I've never had a clogged cat. My '95 K3500 went 155,000 miles on the original and still had low back pressure.

It's important to fix any "miss" or SES condition quickly so as not to degrade the cat.

But if you've had misfiring, especially if it's been happening for a while, consider your catalytic converter's life to be diminished accordingly and your exhaust system back pressure to be higher also.

Higher back pressure lowers your engine's theoretical maximum efficiency (your mpg will suffer).
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#3 fossil

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Posted 05 April 2006 - 01:34 AM

very unlikely

#4 lrymal

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Posted 05 April 2006 - 06:31 AM

very unlikely

<{POST_SNAPBACK}>

And only likely if one adds a lot of additives on a chronic basis that aren't cat friendly to the fuel. We also have a few 150,000+ mile vehicles with the original exhaust with cats. No problem at all with them.

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#5 rmreid

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Posted 05 April 2006 - 06:37 AM

I had a 2003 5.3 Z71 Avalanche that had a clogged cat (passenger side) at 60,000 miles that was covered under warranty.

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#6 ChevyTech007

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Posted 05 April 2006 - 09:37 AM

I had a 2003 5.3 Z71 Avalanche that had a clogged cat (passenger side) at 60,000 miles that was covered under warranty.

Yelp, PCMs and converters covered 8 years 80,000
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#7 Tucson_02Silverado

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Posted 05 April 2006 - 04:07 PM

clogged cats would be from too much sulfer in the fuel, such as some found in Mexico or way too rich with saturates the substrat material with fuel or way too lean which creates high temps causing melting of the substrat.

Then as some have experienced...not necessarily clogged, but classified as screwed when parking over tall dry grass...flame on!
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#8 mcreyaufmiller

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Posted 06 April 2006 - 09:12 PM

I just had mine replaced after 170,000 miles. It has been clogged for about 10k that I can remember, I lost a lot of power and in the last days, the motor did not want to stay running at idle. With the new high flow cat, the truck is once again a beast, of course, the tranny is still in need of a rebuild, but it is still a beast.
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#9 ken1mod

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Posted 07 April 2006 - 09:58 PM

When mine was clogged on the motor home, I got a chance to look at it. It seemed to be simply dirt, almost like vacuum cleaner dirt. I think bad air filtration could be at fault. If you take off the air cleaner, dirt will go right through the motor and lodge in the tiny converter passages.

Ken

#10 chev9644

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Posted 31 July 2007 - 08:00 AM

My 96 K1500 silverado 5.7 Vortec keeps giving me a code "P0430 = Catalyst Efficiency Below Threshold (Bank 2)". I've replaced the O2 sensors fairly recently so i don't think that is the problem. This truck has 163,000 miles and the catalytic convertors have never been replaced. Does that sound like the problem and if so is there a fairly cheap universal replacement for both catalytic convertors? I know the factory set up with pipes to the manifolds is $300-$500 so i'd rather cut out the old cats and weld in new ones if possible. It also has a "P1403 code = EGR valve pintle position" could this be causing the P0430 code to happen?