Is it necessary....

[96redcamarors]

If I gut my cat is it necessary to get an O2 sensor? What exactly does an O2 sensor that i need do?

[pvtschultz]

There is an O2 sensor that is located after the cat to moniter the emissions performance. You will need an O2 simulator to trick the computer into thinking that everything is cool. If you have emissions, you will still fail. If you don't have emissions, why don't you just remove it, or do a more sensible thing and get an aftermarket hi flow cat?

[96redcamarors]

I dont have to worry about emissions. what happens if you dont get an )2 sensor to trick the computer? anything other than the SES light coming on?

[pigglyroot]

you'll be reading off and it'll either lean out or richen your fuel mixture, therefore either making you run like *** or burn alot of gas (sweet, it rhymed)

[Ted]

Ok wait, on my muffler setup now I'm not even using an o2 sensor (the one on the y pipe is still there) but the one that is supposed to be out of the cat is gone. Is this hurting me in anyway. Piggly are you saying that his happens as a cause of no o2 sensor in? Or will i be alright with running with it out?

[sped214]

As far as I know (correct me if I'm wrong, I know everyone will), The O2 sensor behind the cat does NOTHING as far as timing or fuel mixture. It's sole purpose in life is to let the PCM know if the cat is working. The O2 sensors on the manifold, and the pre-cat sensor are used for fuel adjustment.

[pvtschultz]

That is what I am thinking too. You have 3 other o2s to do the work, the fourth I think just moniters the cat. You'll just have to put up with a SES.

[96redcamarors]

Can you install the O2 sensor later on or is it something you have to do once you put the pipe in in place of the cat?