so my catalytic converter is clogged and no emissions or anything around here so I was going to gut it, but I noticed there is an O2 after the cat. what is it going to do if I gut the cat with it there?

 

Pop a CEL. The light will not effect anything, but it will be an annoying light on the dash. The only real danger here is that if a serious problem pops up, it may go un-noticed because your CEL will already be illuminated.

If you cut out or gut the cat, then use a non-fouler in the O2 bung and plug the sensor into that to get rid of the CEL.

Will cost you about $5 at any auto parts store and is commonly done...

 

Basically the O2 sensor after the cat. is only there for monitoring if the cat is working or not. No harm in gutting the cat, you'll either have to look at your check engine light being on all the time or buy an O2 simulator that "tricks" the computer into thinking the cat is working just fine.
My cat. took a dump once and threw an inefficency code, I didn't notice any change in MPGs or how it ran at all so I just let it go, my dash was already lit up like a christmas tree anyways.

 

alright thanks guys, that's what I was thinking but then last night some one told me the 2 o2's worked together and controlled my a/f so I just had to make sure. thanks for the help

 

No if you have Cali emissions then there's 2 pre-CAT sensors that work in conjunction to control air/fuel mixture but any sensor post CAT only monitors performance.

 

alright cool, saves me a ton

 

Yep

After CAT O2 sensors don't do anything for the air/fuel stoichiometric monitoring. The only thing that it does is monitor the the CAT. The stoichiometric mixture is monitored by the pre-CAT O2 sensor/sensors only.

 

hi! some time my car working without CAT, but i don`t have check.
why?

 

Look at you hydra! I didn't even know how to spell that until now LOL

HUH?!

 

lol @ widow, i agree i have no clue what he is saying.