Recently got my new exhaust installed, HKS hiper.

I did the installation of the exhaust myself, with the help of my friend. When I was under the car unscrewing the bolts for my stock exhaust, I saw that a wire came down and was connected to the exhaust bolt.

By "connected" I mean that the wire was wrapped around a piece of metal that was put in between the bolt and the pipe the exhuast is connected to (mid pipe?).

Does anyone know what that wire was for? When i installed my new exhaust, I didn't place it back in the same place.

 

no idea, but hey how u like it otherwise? i got that exhaust on its way now...any pictures? haha, anyway hope its nothing too serious...

 

That's the ground for the exhaust system that is primarily for the O2 sensor - put it back.

Tom

 

^^ as he said. You may experience lumpy idle and bad O2 sensor readings without it.

 

I just pulled my stock catback to re-paint it black and polish the tips. I was aware of this wire (from this thread) before I pulled it but forgot all about it when I was in the garage.

Sure enough there is a chunky ground cable hanging down grounding the exhaust to the chassis, no crimp on the end, just bare wire, and it didn't look like it had been connected to anything. Do my thing, bolt the exhaust back on, connect this wire to the bolt between cat-back and cat and what do you know - my idle is marginally smoother.

I'll get the appropriate connector and crimp it on properly when I'm under there next.

 

whew, probly good i read this so i can watch out for that...

 

ground for the exhaust system that is pri for O2 sensor??? I have no idea what this is. Someone please explain.

 

I really like the exhaust. Its actually a lot quieter than I thought it would be. It has a nice clean, but deep tone to it. I definitely feel the difference in power..

The only mod I have is the exhaust, so depending on what your actual set up is, you'll find varied but similar results.

 

It's the ground for the o2 sensor. put it back so you don't experience idle problems and o2 error readings. (hope that's lamens for ya)

 

The wire you have, it's the ground for the o2 sensor. Ground it so you don't have more problems with the car and experience bumpy idling and o2 error readings. (hope that's lamens enough for ya)

 

I realize that if I don't place it back on the exhaust bolt I'll experience a bumpy idle.. what I don't understand is what an o2 sensor is.
thanks

 

It reads oxygen levels in your exhaust gases and relays that back to your ECU so it can make the appropriate fuel mixture changes. All cars have them.

 

thanks for the info. So the o2 sensor is neccessary. dammit, now I have to mess w/ my exhaust and try to put it back on.

 

I was a bit baffled by it because it's just a short wire grounding the exhaust to some point on the chassis. I guess It's important to make sure the exhaust has a good ground, because I think the O2 sensor screws into the downpipe/pre-cat assembly doesn't it? So it would use the exhaust as it's ground reference, and not having a good ground reference = dodgy readings and lumpy idle.