o2 sensor aft the cat

[2wickedtoyz]

when i do the new system in my car i want to remove the cat but i'm affraid the third o2 sensor depends on the cat to keep the car running normal or am i blowing hot air? i would just like to know can i remove it without any consequences...

[userlain]

why the hell would there be an o2 sensor after the cat? correct me if im wrong but all the oxygen burns with the gas in the engine.

[EKam]

If you have OBDII, which means you have the o2 sensor after the cat, and if you remove it, the engine light will go on and your ECU will go into safe mode.

Personally I don't think it's worth it by going thru this much trouble.

[userlain]

after you remove the cat just disconnect the negative cable from the battery for like 15 minutes. this shoudl reset the comp

removing the cat really isn't worth all the trouble for the very minimal hp gain

[EKam]

Originally posted by userlain
after you remove the cat just disconnect the negative cable from the battery for like 15 minutes. this shoudl reset the comp

That'll just stop the engine light for another few days from going off.

[2wickedtoyz]

thanks ekam i thought so

[zoni]

If you have OBDII, which means you have the o2 sensor after the cat, and if you remove it, the engine light will go on and your ECU will go into safe mode.

this is false...

if there is no sub oxygen sensor present, the ecu will use preprogrammed values in place of the missing readings...

[white90dx]

Originally posted by Zoni_Camry
this is false...

if there is no sub oxygen sensor present, the ecu will use preprogrammed maps in place of the missing readings...

The ECU does not use the secondary O2 sensor for tuning - it is only to verify that emissions systems are working. You will get a CEL if its removed (or left in there without a cat in front of it). There are mechanical and electrical ways to fool the second O2 sensor into thinking it has a good reading...

-Charlie

[zoni]

This is for the 1mz...

[2wickedtoyz]

so what does all this mean? has anyone else gone without a cat?
and has a 1mzfe w\3 o2 sensors

[Calvin327]

From my experience of taking off the cat has a good side and bad side. The good think is if you do intend on running straight pipe without a cat, you'll get straight flow which means more power no restriction. Bad side is that you won't pass smog emissions and your car will be loud as hell, I'm talking about hella loud high pitch kind of sound. As far as the engine check light goes and other worries, there won't be anything like that if you connect the pipe right. I did mine that way. When I installed my brospeed headers I elminated the both cats on my car, the one on the manifold and the one on the downpipe. Never had any problems with my car as far as that goes.

P.S. There are 2 02 sensors.

Calvin

[white90dx]

Originally posted by Zoni_Camry
This is for the 1mz...

Uhhh... yes, I gotcha. I have a friend with a 230whp 2000 Camry V6 auto... The rear O2 sensor does nothing for tuning. The car runs no different with the cat inefficiency CEL than it does without it. You MUST have the front O2 sensor(s), but the rear O2 sensor doesn't matter.

The picture you attached is for when the car is in "safe mode" which only happens for certain engine/sensor malfuctions.

If you would like more information on the fixes so you can run catless (or with a single high-flow cat), PM me and I'll find the information for you.

-Charlie

[2wickedtoyz]

i just don't want my car acting like sht and i do plan on leaving that sensor there(my a\f gauge is connected to it) but i just don't want to buy another cat and i know mine needs to be replaced. the car is registered in sc and my home of origin is fl(niether has emission laws) but i'll be buying another(cat) when i can afford it but for now i want to run without.you get what i'm saying?

[SuperSolara]

You can run without a cat and not have a check engine light if you install a oxygen sensor simulator. It "fools" the ecu into thinking the signal from the rear oxygen sensor (the one that "rats you out" if you don't have a cat, or if the cat simply is not working properly) is fine.

[2wickedtoyz]

the point is i don't wanna spend the extra money and i don't want to risk screwing up my car