Greddy Cat Back Exhaust, Why does there always have to be a prob! Options

[Milds3vn]

Could someone help me out here? I got a Greddy SP cat back exhaust for my '97 ST. I haven't put it on yet because I got it Friday and I was about to rip off my stock exhaust when I noticed that there is an 02 sensor after the Cat but before the rear axle. If you look at my profile picture the sensor will have to go in customly on the really long straight pipe right after that thicker cylinder peice(whatever that is called)(not the pipe with muffler, the other). I didn't know if I would need a special part to weld in so the sensor could screw into the exhaust (because it screws into a nipple fixture)which is welded into the exhaust(but not pre drilled for the Greddy). Most parts places were closed so I didn't try it for fear of being stuck with a non running car(or illegal). Whats the deal with the sensor im describing? I guess it's so the ECU knows what the emissions are like after the exhaust gases go through the cat but I thought that was registered in the header pipping. I hope this doesn't cause a problem if I get higher flow cat and the sensor reads a dirtier exhaust measurement and cuts the fuel back. Do I need this sensor or is it bull$hit? Luckily my father's shop has a pit I can drive my car over to work underneath the car which is how i noticed the sensor. Do I have to cut a hole in my pretty new exhaust and weld in this O2 sensor or can I just be a rebel and not put it in? It pissed me off so much cause I wanted to bolt that bastard up so bad and hear that throaty sound that its supposed to make. Hopefully those of you that have this exhaust can let me know what you did. Nothing good is ever easy!

This post has been edited by Milds3vn: Feb 18, 2003 - 10:12 AM

[Blackcelliman]

I have the same problem that you do. I have an st and there is no place to put the o2 sensor on mine too. My oringinal plan was to take off the old piece from my old exhaust and weild it on, but what we're gonna do is get some resistors to fix the problem. I'll post my results at a later date when I get it done. My friend's a mechanic and he knows exactly whats going on, so I'll give details later.