ok well i finally got my downpipe welded back together and reinstalled the O2 sensor. however, after resetting my ecu, as soon as my car started to boost the CEL came back on. i checked it and sure enough, 41. so could it be that because im running an FMU (yeah i know they suck, =death, will blow up my motor, etc.;please i dont want this to turn into a lecture on why i should not be using an FMU, ive had plenty of those already and it will be replaced soon) that its making my A/F ratio way too rich and thats why im throwing a O2 sensor code?

 

02 sensors go bad often. you could just have a bad sensor. there cheap, i would replace and see what happens.

if your running a FMU it only adds fuel under boost, so if your throwing the CEL when starting the car i would say you have other problems. remove the FMU (for testing) and see what happens.

if you have access to a wideband, hook it up and see what your A/F is

platinum.

 

the O2 CEL only came on once i hit boost. when i started the car and before i hit boost i was good and had no codes pop up.

 

I was having the same problem when i was running my drag kit with the fmu?I replaced the o2 sensor twice and it always came back?

 

did you ever get it fixed? if so how did you do it?

 

I never could get the cel to stay gone.I ended up doing a full build with an ems before i could figure it out?Sorry but i was also thinking the same thing regarding the rich mixture.

 

thanx for the help anyway