Hey all, I just finished getting 2.5" piping installed from the manifold all the way to the back. My car has 2 O2 sensors. I know I have to get a bung for the O2 that goes on the downpipe, but would I still needto weld a bung for theO2 sensor that goes after the cat? and if I don't, would it affect the car in any way or mess with computer??

 

Yes, you're OBD2, and you NEED that second o2 sensor

 

Thank you

 

ok...yes your car is OBD2 and technically you "need" that sensor, BUT the only thing that sensor does is monitor cat efficiancy. it WILL NOT effect drivability what so ever! the worst thing that will happen is your check engine light will come on and you will fail emessions due to the check engine light. I have seen cheater sensor "caps" that trick the ECM into thinking the cat is working fine even it there is no cat and its not legal but who cares. most four bangers will pass emissions with out a cat!

 

my cel came on on my 07 si i got a 4 to 1 race header would i need to change my o2 sensors? What can i do to turn the cel off?