hey i got a 2003 oz rally im bout to put on performance headers and the high flow cat aka test pipe from rrm and a cat back exhaust somebody told me to just leave the o2s off and buy the plugs for them or just change them and have the cel on all the time has anybody had this done or what not im trying to see what my options are

 

well if you dont have o2 sensors then your computer doesnt know "what" to do. you computer takes the reading from the 2 o2 sensors and makes an estimated guess on what to do with the given information.

 

You loose miles per gallon for gas. I had the same problem, and i beleive i need to replace my other o2 sensor by the headers.
Best advice is to find someone who knows what there doing help you out, cause the person who i bought my lancer off of didn't take that route.

 

Dont take them both off. Our car's have 2 02 sensors 1 is pre-cat 1 is post-cat. The first 02 sends it's inputs to the ecu in reguards of fuel, It is very important. The second 02 on the other hand is just there to detemine the condition of the cat. So you can remove this sensor but your check engine light WILL be on. I am currently and have been for the last year and a half without a rear(post-cat) o2. And last time i checked my mpg i was at 37.25.

 

Here's what you need to do go to your local parts store and ask for spark plug antifoulers. they should come in sets of two make sure they are 18mm. Take one and drill it out so its straight through but make sure you can still use the threads. Then take your rear o2 and thread it into this one then thread the 2nd anti fouler on that. What this does is pull the o2 away from the exhaust stream causing it it get a cleaner air to it. So you still have no cel and all sensors cause the ecu thinks the cats working great.

 

^+1 that's what i will be doing when i go turbo tired of the dang CEL light.

 

RRM also sells a CEL eliminator which is just a purpose made version of the homemade version. It screws into the second O2 location and removes the end of the sensor from the actual flow of exhaust. Ive been running one with an aftermarket header/midpipe/exhaust for about 4 years and have never had a problem.

 

why are all these posts going up in the forced induction tech pages doesnt this fall into another category