im planning on doing pacesetter headers and a custom 3in y-pipe with NO CATS, and plan to have ALL 4 o2's welded back into my exhaust... my question is can't i just have my REAR o2's welded back in?? im trying to see exactly WHY o2 sims are needed... i know their needed if you REMOVE your rear o2's but what if i just put them all back in.. that will work right??

 

why would you want them in? since you will be running no cats, you'll be constantly setting off the SES light, although a low signal from the rear o2's does absolutely nothing to the performance, just the nuisance of the SES.

if you are gonna run sims anyway, what is the point of having the rears welded back in?

 

lol no dude i wanna run the STOCK o2 sensor's INSTEAD of having to buy o2 sims... but i wanna know if it will work or not!

 

But you're not going to have cats. It's pointless to run the rear O2s w/o cats.

O2 simms are needed if you remove the cats, not if you remove the rear O2s (well, yes they would but that's not what we're getting at).

If you remove the cats, you can:

1: Drive around with the SES light on. No biggie, just a little annoying.

2: Buy O2 simms...and the SES will go away.

3: Delete the rear O2s (PCM) and then you won't have to run O2 simms...and no SES light.

If there are already bungs welded in for the rear O2s, just go to Home Depot and buy a couple bolts (that'll fit) to stick in there.