First of all, thank you to Nakaiya21 for writing this up.
https://www.cobaltss.net/forums/show...light=downpipe


I installed a ZZP catted downpipe on a buddy's car, today. Reading that some have started throwing codes after install, I was wondering if the issue is with the O2 sensor removal. I'm not trying to say anyone on here is a complete idiot, but some may not know that unscrewing the O2 sensor with the cable still plugged in is an easy way to break a wire. I think that #4 should be changed to just unplugging the O2 sensor, clearing the cable from the heatshield, and removing the downpipe with the O2 sensor still installed. This would remove the possibility of breaking a wire while trying to unscrew the O2 with the cable still plugged in.

Just follow the wire from the post-cat O2 sensor to the plug. The wiring is wrapped up inside the tinfoil-like heatshield. Just unwrap the wiring and unplug the sensor. There is a blue platic lock that has to be removed before you can unplug it, and it is accessible through the driver's side wheel well, or from the bottom, but you need to have skinny hands.

Pic of plug for O2 taken from driver's side wheel well:


Downpipe removed with O2 still attached:


Be sure to install the O2 sensor in the new downpipe before installing the downpipe back in the car.


I don't know how to go about suggesting this for a change to the DIY, but I think it would be a good idea.

 

I like the idea...granted I had not problems getting the DP off and then taking off the O2 sensor after...but I probably wold have done it that way had I known it was so easy to get off...I just assumed it was a PIA because I know on the LSJs it's a pain in the ass to unplug..

 

I still don't understand how you would unscrew the O2 without unplugging it, though. That causes you to twist the wire really badly.

 

Interesting, I can see it being very easy to happen.

Some live and learn, question is how many have fixed this and not relayed it?

 

Does our lnf o2 sensor have the wires built into it?

 

It didn't look like there was any kind of electrical rotary union.

 

Easy...take downpipe off...unscrew the O2 sensor while spinning downpipe in the opposite direction...either way works...but yeah you definitely don't want to twist the wiring up on that thing.

 

I installed my dp then after I plugged the o2 in and no problems whatsoever

 

They have enough slack on them that I don't think it's a problem. When I used to work at a shop that's how they always did it, the key is to spin up the wire the opposite way before you put the O2 back in so by the time it's tight the wire is straight

 

i unscrewed mine the 1st time with it plugged in lmao. i had to get a new one. damn fragile ass new cars

 

Thats the first thing I did. I reached up from under the car and unplugged the sensor from the harness. Then I went to work on the DP bolts. I did put some anti seize on the sensor before I put it in the new DP just incase I needed to pull it off later on.