i have a 2009 Honda Pilot and the underbody Cat rotted out , it is after the o2 sensors and wasnt throwing code. i replaced it with a straight pipe since we dont have to do emission tests here anymore (Ontario, Canada) since this cat is after the o2 sensors and each bank already has the pre cats before them that are fine, is it going to throw my car off in anyway or i am fine?
It will mess with your computer because your car is essentially polluting more and it is going to see there's no signal coming from the catalytic converter. It's not good for your motor to run without cats unless you have the vehicle tuned for that. Otherwise your ECM and PCM are basically stuck in permanent freak out mode.
I think you can be fined for circumventing/bypassing emissions systems.
A Cat delete is illegal. Even though they don't do testing there if the OPP notice the delete you will be changed.
forgot to mention that this car has two other cats that are pre O2 sensors and this is the 3rd underbody cat ,no O2 sensor near it ,before or after. No emmison tests here anymore
are you sure it's not a resonator?
yea im pretty sure
Ive never seen a cat before O2 sensors. Usually flex pipe but never a cat.
@joesky
There is such thing as a catalyst that is not monitored by o2 sensors in the midpipe section of the exhaust. My BMW has a remote second catalyst with no sensors. It will be just fine replacing it with a straight pipe actually since you're freeing up the exhaust flow. But I still feel like that third catalyst you're talking about may have been a resonator as someone else mentioned. Did you see cells inside of it?
My 04 Prius original factory exhaust pipe has the downstream O2 sensor positioned between 2 cats, so there's one before and one after the O2 sensor
You need to get any O2 sensors that were in the cat back in the system somehow if there were any. Not sure about a pilot but on civics and accords everytime one of these fast and furious wanna be’s do a cat delete the downstream sensor goes bye bye. Car ends running like crap. VTEC kicks in and all that extra fuel goes right out the tailpipe in a big black cloud.
A lot of cars have a post O2 nox cat and as long as it’s not monitored it will not hurt anything removing it
okay yeah just wanted to see if someone could confirm this too, thanks
car runs great , no issues thus far about 1-2 % on the long term fuel trims and ive had this for about a month of driving now