O2 Sensor Questions

[ViciousBlack97]

I took the Cobra to get tuned yesterday, and Dan at Pro-Dyno told me the car wasn't even recognizing the front two sensors every few pulls. I put new sensors in about a week ago, so that leads me to believe that there might be a wiring fault somewhere. I would think wiring would only affect one of the sensors though. Plus, after the tune, the idle seems to be hanging pretty badly. Could this be caused by the o2 sensors too?

 

[oldstv]

Are there any codes showing up?

 

[ViciousBlack97]

No, that's the odd thing. There aren't any codes at all..... on one pull it would read out 13.0 A/F, exactly where he wanted it, then on the next it wouldn't read anything...

 

[mwolson]

The PCM doesn't watch the O2s during WOT runs. They are only used at idle and part throttle.

 

[ViciousBlack97]

He said they wouldn't affect open throttle runs, just low load cruising. Especially when it was raining or there was moisture in the air that could cause the A/F to be slightly different. I still have no idea how two brand new sensors could be faulty, so I'm looking towards the wiring.

 

[ImThatGuy]

Thats strange, maybe the ground wire they use when tuning, after O2's are hooked into, wasnt seated properly? Just my guess, ive had some freak/ strange pulls due to that.

 

[ViciousBlack97]

Thats strange, maybe the ground wire they use when tuning, after O2's are hooked into, wasnt seated properly? Just my guess, ive had some freak/ strange pulls due to that.

I've got no idea why it would happen :shrug:

 

[iamtheshaner]

Narrow band conventional 02's don't read A/F ratio so who knows what this guy is seeing if he's telling you that. Although the signal isn't used as feedback during WOT it should still be getting to the PCM.

More info on how the data was logged, what the voltages were actually doing, ETC is needed for any solid help

You get what you pay for when it comes to 02 sensors, I wouldn't be completely shocked if you bought garbage sensors but I wouldn't suggest you chuck two more at it without a little troubleshooting...