Stomis

Ok I know theres 2 sensors in my exhaust. One pre cat and one post. Are they both o2 sensors? I'm getting ready to run some new exhaust because I have a broken joint. Just wondering if my post cat sensor will need to be re-installed in the new pipe and if hollowing out the cat will affect anything in the computer.

Stomis

Anyone?

pruney81

3.0 or 22re?

Stomis

its a 3.0

CoedNaked

I got a 3.0 and I only have one sensor and it's before my CAT. That is the O2 sensor. Don't know why there would be one after your cat on your model of truck/engine, etc.

Do you have an anomoly or is it because mine is just a Canadian model truck?

YotaND

My understanding, and I could be wrong here is that the 2nd sensor behind your cat is an O2 sensor. From what I gather it does not effect your fuel air mix but is there to check if your cat is working properly. It is like an emmision check. If you remove it your truck should run fine but you will have a check engine light uless you add a O2 Simulator. Also if you remove your cat and leave the 2ns sensor in you will get a check engine light. I hope Im not lying to you and I hope this helps.

Red3.slow

Not on the 3.0 I'm pretty sure.

91muddog

my 22re has the same setup.
ive seen some yotas with them and some without them.

Try YotaND's suggestion, it should work.

As for the cat just make a straight pipe with the tabs on the end to bolt in place of the cat ^-^ thats my plan after i get it smogged or if i get a 94runner. that way when you have to get smogged just sawp and smog it andswap back

mt_goat

If you have a vehicle that came with 2 O2 sensors (but I didn't know any of the 3.0s did), then yes the 2nd sensor is there to make sure the cat is working properly and the ECU will throw a CEL if you gut the cat. BTW that cat has about $140 worth of precious metals inside.

Brenjen

My 3.0 only has the single O2 sensor before the cat. California models may have two; I think they do but I could be mistaken.

Red3.slow

See I don't know about that I've been running with out a cat for a while and I believe i've lost low in power and fuel economy. I plan on replacing it with a high flow cat soon.

pruney81

Only the California models had two oxygen sensors. His must be a california model even though his avatar says Jersey.

Stomis

Yeah its definatly in NJ and definatly has two O2 sensors. I wonder how the truck made it across the country, time for a carfax I guess...

As for the $140 precious metal comment is that suppose to be a reason not to gut it or are you saying to sell it and put a straight pipe? Here if theres no cat shell and a cop really want to break your balls he can give you a summonce for court where at the extent of the law they will fine you $5000 for breaking emissions laws.

mt_goat

Just something to think about. I've heard of some guys throwing them away not knowing the valve of them at the recycle places. I put on a cheap $60 Carsound cat on mine, and recycled the old one. We don't have any emissions tests here though.

doug

you guys are wrong about the sensors being on cali models because my 90 4 runner is from cali and i have only one sensor before the cat

mt_goat

It may have just been like 95 and up CA models.

Brenjen

And possibly the vehicle wasn't shipped for the California market. Maybe it was shipped for sale in a different state & was taken there afterwards by one of the previous owners.

You would really need to run the vin to find out if the vehicle is a California or federal model.

FredTJ

As already mentioned, if you do, in fact, have 2 O2 sensors, then the downstream one is for the cat., checking to make sure that it's working and without it you'll throw a CEL..

FWIW, you'll gain nothing by removing to cat., no power gain, no gas milage gains.





Fred

Stomis

I find that hard to believe. Your telling me Toyota actually put a CAT on there that flowed enough for the motor? I've never owned nor seen a stock car that didnt have an improvment with a gutted cat. Maybe too much v8 experience?