Anyone running no cats?

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PuroPinchePedo

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I bought a 2009 Tahoe LT FLex Fuel. The cats are trash and rattle like crazy. I want to completely replace the exhaust system and add headers. The majority of headers I see like these:

http://tinyurl.com/zwgyjen

Basically, bypass the cats. I'm ok with that but I don't want a bunch of dash lights as a result of it. So anyone doing this and how is it working? Thanks in advance!
 

retiredsparky

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I don't think you will see a check engine light. I do not believe there is any sensor in the exhaust after the cat. When doing the exhaust, you do need to reinstall the O2 sensors to avoid any stored codes and a light.
I assume that you don't live in an area that requires emissions testing? Cause they would look for missing cats.
 
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PuroPinchePedo

PuroPinchePedo

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I don't think you will see a check engine light. I do not believe there is any sensor in the exhaust after the cat. When doing the exhaust, you do need to reinstall the O2 sensors to avoid any stored codes and a light.
I assume that you don't live in an area that requires emissions testing? Cause they would look for missing cats.

No I live in Texas. Our inspections are pretty quick but there aren't emissions testing.
 

01Konvict

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Don't have any idea why this is posted in the Lifted section for headers with cats....

You have 3 sensors on the Y pipe. Two are before the pre-cats near headers for AF ratio, these will stay and need to have for safe running of engine. The last one is the true cat after the two headers meet. You can delete that sensor but need a tune or programmer to do it so no lights show up in the dash.
 

Jason_S

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Your inspection in Texas should include plugging into your OBD2 and reading codes/verifying readiness. If your engine wont go closed loop, it wont read ready and should store codes associated with whatever is keeping it in open loop.

You basically have 2 sets of O2 sensors. Pre cat o2 sensors are used for your fuel trims and will be unaffected by removing the cats. Post cat O2 sensors are there to monitor cat health and will definitely store CEL codes if the cat is removed. Sometimes they can be fooled by the anti-fouling spacers for spark plugs.

Your post cat O2 sensors could have the codes programmed out with a tune. This would allow you to 'pass' that portion of the inspection. However, if a physical inspections is actually done and there does not appear to be any cats in place, then you will fail.

The techs are licensed through the state, if they are caught passing an obviously failing vehicle, they will lose that license and will be subject to fines and penalties. Some will risk it, many will not. I have never personally heard of, or known of, a tech that was caught though, I know and have known many techs that would fail you for something as minor as tint.

If you live in a county exempt from emissions testing, then you have a better chance of skating.

At the end of the day, these changes are minor and everyone has an opinion. Honestly, I was always more surprised when a tech would let me skate on an issue from the inspection. I mean, why should he risk his job for a stranger?
 

dirtydenali07

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I live in north central PA in a very rural county. Though we do not have emissions testing, they do perform a visual inspection of all emissions equipment, including the exhaust. If any of the cats are missing, they could fail you. You could purchase some hi-flo cats to replace your bad ones and remain "legal" emissions wise.
 

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