Just wondering, since there are two O2 sensors on civics, do you need both connected? The first O2 sensor is on the header and the second one is on the CAT, now I've heard some people say that they went straight pipe with no CAT so that got me thinking that your car could run fine without the CAT O2 connected right?

 

Im runnin with only one censor in the header, and everything's fine.

 

Does your check engine light still come on?

 

No, when I installed my exhuast, no engine light came on. When I installed the manifold and a TB, then the light decided to pay me a visit. However, dont know if this would vary from say a 5th gen to 6th.

 

on a 6th gen as soon as you unplug it and run the car warm it will throw it, you have to get an o2 simulator to run cat-less

 

yes for 6th gens like mine it comes on if both arent working propery, so i got a simulator should be here soon...

 

Im not running CAT less. Ii just did an EX exhaust system on my LX and the O2 wires aren't long enough to connect to the new placement of the CAT. Im planning on extending the wires and reconnecting it.

 

I got another question, when extending the O2 sensor, should I extend the wires on the O2 sensor itself or should I extend the wires that connect from the engine bay?

 

when i did mine i spliced the O2 sensor and soldered a 6 ft extension to it... worked just fine

 

my friend told me that If i disconnect the ground on my battery that the check engine light would go off after I have connected my O2 sensor. I did that and the check engine light still came on! I was wondering since I extended the harness about 15 feet, if that would cause a problem?