Catalytic Converter

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Marcos Beltran

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So with these crazy prices on catalytic converters now a days if i were to cut it out and put a straight pipe will it affect the way the truck runs/drives? I know the engine light will come on but i can live with that. Just take the bulb out. Just dont want it running like crap. The truck is 25 years old and im pretty sure the cat has never been replaced. About to replace part of the exhaust cause it is rusted out and dont feel like paying those ridiculous prices. Its a 96 GMC Sierra vortec v6.
 

Frank Enstein

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I don't recommend it. It's a $10,000 fine to remove it Federal Law. When to check engine light goes on it may put you in Limp Mode and it will run poorly. My 2003 Chevy truck had 453000 miles on it when I sold it and it had the original cat.
Is it running bad?
If it's just the cat and the upstream pipes are good the APH-608227 ($155.99 @ Summit Racing) is a legal cat for your truck.
 

stutaeng

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OP, the Catalytic converts/O2 sensors are for emissions and for fuel economy. If you are in a non-emissions county, you can probably remove the cats, but truck won't run optimally is what I would think. I personally would try to find replacements. And if you remove the CEL bulb, when you actually have a problem you won't know since your CEL will never illuminate.

BTW, I don't believe there is a federal law about this. At least here in the State, only the densely populated counties check for emissions. Otherwise state inspection is just a safety check (no emissions check.) Different states have different requirements. Some states don't check emission altogether, while others are really strict.

https://www.dps.texas.gov/rsd/vi/inspection/inspectioncriteria.aspx

I'm surprised you can't find replacements, but I know the thieves are going around stealing them, that's probably why...
 

Marcos Beltran

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I don't recommend it. It's a $10,000 fine to remove it Federal Law. When to check engine light goes on it may put you in Limp Mode and it will run poorly. My 2003 Chevy truck had 453000 miles on it when I sold it and it had the original cat.
Is it running bad?
If it's just the cat and the upstream pipes are good the APH-608227 ($155.99 @ Summit Racing) is a legal cat for your truck.
Honestly havent noticed anything wrong with it but figured i would replace it as the truck has over 179,000 miles on it and it was mistreated by the former owner. But hell if it aint broke then dont fix it huh?
 

sntrym

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You can have the post converter O2 sensors tuned out, but the truck might not run as good. Those after the converter tell the computer if the converter is actually working. As you mention, if it's not broken, why fix it?
 

alpinecrick

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So with these crazy prices on catalytic converters now a days if i were to cut it out and put a straight pipe will it affect the way the truck runs/drives? I know the engine light will come on but i can live with that. Just take the bulb out. Just dont want it running like crap. The truck is 25 years old and im pretty sure the cat has never been replaced. About to replace part of the exhaust cause it is rusted out and dont feel like paying those ridiculous prices. Its a 96 GMC Sierra vortec v6.

I replaced the the CAT down pipe section (with a Walker) on my 96 5.7 motor with 250K+. I'm not sure why I did.o_O In hindsight I think the original was fine (and I'm keeping it for a spare). And if the truck is running and not throwing a code deleting the CATs isn't going to make it run better. The CAT's on these trucks seem to be of excellent quality and short of running really crappy gas for a long time it seems they still have a serviceable lifespan even on 25 year old trucks.

Before going to all the potential agony first go the trouble of pulling the down pipe section and shine a light in CATs to see if anything obvious like chunks of the grid are missing. Otherwise you may be going to a lot of trouble to fix something that's not broke.
 
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b454rat

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I took the gutted cats off my 98 Tahoe. Jegs has an offroad intermediate pipe thats 100% bolt on. Before I couldn't spin the tires, after it would smoke both of em. I put spark plug non fowlers in, check engine light hasn't come on. Where I am, technically has to be on for inspection, but no ones cares anymore. Long as everything works and is safe, and no check engine light on, they don't care.
 
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