i just got my obx headers today and im gona install them, but befor i do i just wana know wut to do with the first o2 sensor? i got 4-2-1 headers, and does anyone have any sugestions about the install, im hoping its as simple as it seems.

 

if there is currently no bung on the #4 pipe (where the first sensor is) then you are either gonna have to have one welded in, or you can extend the first o2 sensor to the bung before the 2nd cat. the 2nd cat will now be your first cat.

your 2nd o2 sensor will, no matter what, have to be extended past the 2nd (now the first) cat.

i had a thread on the old site that you can visit here. page 2 has most of the more accurate info.

Just remember this: your computer expects to read the oxygen levels before and after a cat. it doesn't know how many cats you actually have. as long as you have one before and after the cat, you shouldn't have a problem w/ a CEL

 

that, my friend.... is a perfect answer

i would aslo STRONGLY suggest an impact wrench for that flex pipe

mine took a day and a half to get off, WITH an impact and a grinder

 

The 99's only have one CAT. At least mine did anyways. Your headers should have a bung on them for the first O2 sensor. I had to get a second bung welded to the downpipe.

 

it only has a sesor on the flex pipe on the obx header. i have a fx would that make mine any different?

 

boo to that... haha...

I have a CEL with my first 02 sensor in the #4 pipe on the header and the second after my cat... explain that one. my code is "catalyst above threshold"

 

ok so can i extend the first one to the flex pipe then put the second behind the cat? would that work?

 

You know what I think, I think it really doesen't matter what you do . Eventually after installing headers and a cat your gonna get the CEL it's like death it might take a while but its coming.

 

it should work, yes

i flipped a CEL, and the only way i could get it off was a master reset of the ECU by disconnecting the main wiring harness when i installed my deck. i'm not sure if i'm still getting error codes yet because i havn't had it checked since.....

but the light went out

lol.gif

 

yes, you can do that. like i said... as long as you have a sensor before and a sensor after the cat, you should be all set...

cdog is just WEIRD!! tongue.gif