O2 sensor sends a constant 2.96 volts!?

[beatshack]

My O2-F sensor reading on my MMCD usually went up and down while idling like it's supposed to, and now the reading just sticks at a constant 2.96volts, even while full-throttle etc. The car seems to be running alright, so whats the deal here?

Any thoughts? Thanks in advance!

 

[SlowSpyder]

Use a Logger or scan tool to verify o2 voltages. If no logger/scan tool is available then back probe the o2 sensor at the 4 wire connector and also from the ecu.

 

[1stGenRocks]

are you sure you're looking at the right o2 sensor? the stock o2 should only go to .96 or so but the 2nd o2 reading thats not used on 1g's still shows up in mmcd and it sits at 2.6 or so all the time

 

[steve]

I guess you didn't search much on the subject or you would know that O2-F isn't the front, one and only, O2 sensor on a 1G DSM. O2-R is, on the versions of MMCd that have more than one O2 sensor.

Steve

 

[beatshack]

Thanks. I did search, but searching for "O2 sensor" doesn't give very refined results.

In that case, my o2 sensor is sending 0.1v constantly, with no CEL codes being thrown.

 

[BINGchndlr]

then...sensor is dead or you are leeeeean as crap

 

[Knuckles2.0]

my car does the same thing, i was told by a local dsm mechanic that it was more than likely the ecu....

 

[steve]

Iwas told by a local dsm mechanic that it was more than likely the ecu.

While it's possible for this to be the symptom of a bad ECU, I wouldn't rate it as a "more then likely" one without additional data pointing at the ECU.
The O2 sensor or it's wiring is far more likely to be bad. Actually measuring the O2 voltage at the ECU pins would be a quick test. I've yet to have my ECU throw a O2 sensor code but I've had 2 bad sensors so far that caused me to fail emissions.

Steve

 

[beatshack]

I'll test the voltage at the actual sensor wire and again at the ecu pin #4 and post the results.

 

[beatshack]

okay, update:

The o2 sensor appears normal on idle, fluctuates between 0.2 and 0.5v, but when I'm WOT, it fluctuates between 0.8v and 0.1v!!

I am only running 10psi of boost on the stock turbo, but I am pretty sure I have some major boost leaks. Wouldn't boost leaks make me run rich though?

Any thoughts are appreciated.