4-2-1 headers now have CEL HELP - Hyundai Performance Forums

red97tib · 10-01-2003, 12:53 AM

I installed 4-2-1 obx headers on a 2.0 97 tib. I posted a while back what to do about the second o2 sensor. I was told to get a bung installed in the number 4 header pipe. So I did and the second is in the flexpipe. But my CEL came on, probably because the cat is behind both sensors. When I take off it smells like I have a bad cat. So does anybody have any suggestions or am I stuck looking at the CEL?

Kemper · 10-01-2003, 04:02 AM

You want to get that second sensor behind the cat... SENSOR->CAT->SENSOR... that should solve your problem. The CEL will cause your car to perform poorly, but won't hurt it.

**i8acobra** · 10-01-2003, 05:43 AM

Use the bung you had installed in the #4 primary for your first O2 sensor. Plug the bung in the flexpipe with an O2 bung block-off bolt. K&N makes them (the same company that makes filters). Install a second bung after your cat and install the second O2 sensor there. Problem solved.

You can buy the bolt and bung together as a kit here:

http://www.motorsporttech.com/fbody_exhaust01.asp

It's the 13th item down on that page.

Jiggy Verna · 10-01-2003, 08:01 AM

you're car is not performing worse......if the o2 sensor in the header is okay then you are good. The 2nd one just measures to see if the cat is working. It doesnt change any fuel ratios.

WHY ARE THERE THREE THREADS ASKING THE SAME QUESTION WITHIN THREE LINES OF EACHOTHER???

Epiphone · 10-01-2003, 05:47 PM

You don't need to even install the second O2 sensor or go through the hassle of extending it. Just zip tie it up out of the way so it still reads fresh air and cap the second bung hole. That's all you have to do.

beppomarx · 10-01-2003, 06:29 PM

dunno if an open O2 sensor would really work, but if you go that route make sure youre bunghole is plugged :lol::lol::lol::lol:

rbuecker · 10-01-2003, 08:12 PM

Quote:

Originally posted by beppomarx
[body]
dunno if an open O2 sensor would really work, but if you go that route make sure youre bunghole is plugged :lol::lol::lol::lol:
[/body]

and how much tp would you need for that?

Epiphone · 10-03-2003, 11:04 AM

hahaha. It works. A couple of guys on NT.com have done this with no CEL. I am about to do it myself.