Its the Test pipe that doesn't have one.

Ok guys break me down..I'm from an STi...so I can't remember what underneath of my car looks like right now:
header(02)-----cat-----exhaust(02) or how does this go.
header(02)-----cat(02)----exhaust???

so are thier 3 o2's or just 2?

I have a megan (i guess..its 3") DP...then stock cat, then Megan exhaust (that all work fine on the car) what do I need to do.

I'll need to position the bung in the right place on the TEST pipe...in order to use Foulers to back the 02 away from the Exhuast stream?Or pretty much bung it anywhere if I'm using foulers?I read somthing about it had to be toward the passenger side more towards the front of the TP & front of car? whats that about.

Mech fix= fouler trick?
Elec fix =02 sim (which I can't find one on burschur or anywhere.)?

 

OK bro, buy the mechical fix from gruppe-s, thread it into where your sensor SHOULD go, screw in the sensor, and drive CEL free. You may need to extend your sensor wiring, but with a stock like setup, I doubt it.

 

BTW, lancer shop has the perrin cel fix, but it's more than you paid for the pipe!

 

so thers no 02 in the cat?
I think thats where I'm getting confused.

otherwise if a o2 goes in the cat...just weld in a bung on the test pipe and do the fouler trick.(2 spark plug fouler - 1 drilled out etc Trick?)

 

no, the 2nd 02 is in the beginning of the cat-back, where the CEL fix can go that you get from gruppe-s or ebay for $15. there is no bung in the stock cat!

 

better off just buying the real deal UR TP.

Cutting and soldering the wires is easy, mark them first before you cut.....wrap the ends together (its best to spread the strands of both wires and intertwine them) soak the bare wires in ispropyl alcohol, and then apply the solder. The alcohol acts as a flux, it cleans the areas and draws in the solder. Oh, and be sure to put heat shrink tubing on before you solder to cover the bare connections. Presto...professional install. (not only do I do aircraft sheetmetal, I am also and avionics installer!)

 

trust me, threading in the mechanical is much easier, takes all of 5 minutes.

 

cant fault that...