[RESOLVED] o2 sensor reads zero volts

[a91talonAWD]

I have a 1g Talon TSi AWD and just got it running and hooked up the data logger and noticed that the o2 sensor just stays at 0 volts and all the fuel trims(L/M/H) are all 100% at idle and driving. Does this mean the o2 sensor is bad? I have no CEL though.?

 

[twdorris]

Either the O2 sensor is bad or you're running too lean. The fact that fuel trims haven't updated just means the ECU hasn't gone into closed loop yet...which makes sense given the lack of an O2 reading.

Try richening your injector compensation and see if you can get the O2 sensor to move. If you can't do this easily, try just raising fuel pressure as a temporary test. Just do something to get more fuel into the engine and see if the O2 sensor starts to respond or not. If it doesn't, then you can be pretty sure the O2 sensor signal is bad. It might be a bad O2 sensor or bad wiring.

Thomas Dorris
ECMTuning, Inc.

 

[a91talonAWD]

I swapped out the o2 sensor with another used one I had laying around probably bad too. Then richened up the fuel by selecting the smaller injector size of 560cc (I am running 750cc injectors). Then turned up the fuel on the idle via the MAFT as far as it would go and the voltage moved around a bit for like 20 sec then dropped back to zero and stays at zero now. also the low fuel trim went up to 139% and has not changed since the o2 voltage has been steady at zero...I smelled fuel so I am going to buy a new o2 sensor, what do you think? Also on the logger would it say anything about a CEL? I have no Check Engine Light on, is that because of the logger being plugged in?

thanks

I just put a new denso o2 sensor in today... same story 0 volts, but when I hit the pedal it will move around a bit but then go back to 0 volts...i also notice that at warmed up idle my TPS is at 11.3% and the COOL is about 100 degrees till the fan kicks on and never drops below 98 degrees, once warmed up, and never goes over 101... then fan kicks on and drops it back down.

 

[Red97Eclipseboy]

My friends GVR-4 had the same problem. He would almost always be in open-loop at idle. And no matter how much we tried to correct it via DSMlink, nothing would work. Changed the o2 sensor, nothing. It ended up being as simple as his TPS wasn't fully plugged-in. Check yours, and put a volt meter to it.

 

[a91talonAWD]

-properly adjusted the base idle set screw (BISS)
-properly adjusted the throttle cable
-also cleaned the Idle Position Switch (IPS) <-------------- a poor connection in side the switch I beleive to be the culprit for not entering closed loop
-also added a ground from the chassis to the throttle body


thanks for the help all!!