PLX M-300 Odd Issue

[Eclipsethis90]

OK, I searched and no one quite had this problem from what i read. I installed the sensor just after the DP in my off road pipe. I fired the PLX M-300 up and waited till it read "Air", I fire up my car and no matter what I do driving (I know i am running a little rich right now) it will still read "Air" the whole time. I tested the lead (forgot the color) it is supposed to be 5 volts, mine is pulling 4.9 volts. I am a little unsure how to trouble shoot this any further. The positive is hooked into the cigarette lighter circuit, with a ground on the body near the shifter. I am not using the logging wires. I think there may be an exhaust leak at my flex pipe, but i figured at least I would get some readings on this thing. Any ideas?

 

[oldman]

Any exhaust leaks prior to the location of the sensor will cause it to read lean. I had a slight leak at the O2/DP flange and mine was showing 19-20-lean at idle/cruise, after fixing the flange, reading was back to normal. It's very possible that if your leak is larger than mine, you could be stuck on "air" which is beyond "lean".