I have an AEM wideband and an Apexi turbo timer which can display the o2 sensor reading from the ecu. I know this isnt exactly accurate for tuning or anything but when sitting at idle the AEM will read a relatively stable A/F but the turbo timer will fluctuate randomly. Could this mean that one of my o2 sensors is going, does it mean something else, or does it mean nothing at all and I am being paranoid?

 

if you have a stock turbo, theres no real reason to run a turbo timer, in my opinion, during wot, generally 11.2-11.8 range is where you'd like to be, idle, 13-15 or higher depending on your set up, the lower the number the richer you are running, higher the number the leaner your running, lean is worst then rich, hopefully this helps some what.

 

x2^^^

the turbo timer only reads the stock o2 wich is a pretty basic reading if i remember right its only a 2volt split so it doesnt help you much(pretty much a narrow band)

 

Yeah, the stock sensor is narrow band meaning the voltage drops off sharply on either side. A good sensor should vary all the time. So, your reading is telling you something, it is telling you the sensor is working. If it was bad it would produce a flat reading.

 

hmm

 

yeah .... 2nd

 

Up until recently it actually followed the wideband fairly closely. Like within a few decimal places. Now when the arm is reading a steady 14 something and a only changing a few decimal places. The turbo timer now fluctuates from 14 something to 20. When an o2 fails doesn't it read full lean?