one eyed willy

i installed my o/r x about 6 months ago,i tried the mil elim's with no success,light did not bother me too much but i did finally get a tuner and now the light is gone,yepee!

the o/r x adds a good amount of hp for the cost of the pipes.i dynoed my stock car with no tuner or cai at the time,only mods were the o/r x and mid mufflers.272hp, a buddy of mine did his car same day,he had cai and tuner with a stock cats,he was only 8 hp more than me i think.so they are worth it imo,plus they sound awesome!!

howarmat

Unless you told brenspeed not to turn off the 02s, they are turned off in the tune already, so the mils are doing nothing

Blue Meanie

Yes, I had Brenspeed leave the rears on for emmissions testing. In NY, we have the OBD II test where the scanner is connected to the OBD II diagnostic port. If the rears are turned off, it will show on the scanner. The rears are still on and the MILs have taken care of the problem so far.

acascianelli

My question was whether the PCM can still detect if the motor is running rich or lean if the rear O2 sensors are disabled?

Also, is there anything I should be concerned about driving with an O/R midpipe through the winter?

howarmat

yes the lean and rich readings are still good and i dont think there is anything to worry about in the way of winter.

one eyed willy

only purpose of the rear 02's is to make sure the cats are doing thier job,they have nothing to do with any sort of tuning of the car or anything at all,they just let you know when to replace the cats.rip dim b!tchs out!!

2007CalSpec

Maybe you got lucky and the MIL elims worked for you. I guess it's a hit or miss situation for '07 & up. It was Brenspeed that told me the MIL elims wouldn't work for my '07 so I've been living with the CEL on.

rlh6805

100% correct. The rear O2 sensors are sometimes called CMS (catalyst monitoring sensor) sensors. The only purpose they serve is to "watch" the cats to make sure they are properly cleaning the exhaust gases. The off road pipe eliminates the cats and the rear O2's. Yes, the CEL will come on and stay on unless the rear O2's and the cats are in place.

acascianelli

How does the engine determine if it's running to rich or lean then? Kinda off topic but I'm curious now.

rlh6805

The upstream O2 sensors feedback to the PCM the oxygen content of the exhaust. This data is used by the PCM to determine how rich or lean the engine is running. Optimum air/fuel ratio (stoic) is 14.7:1.