What happened to my O2?

[tazgn]

I was just out making some data runs around the neighborhood. I recorded 6 runs (none over 1/2 throttle, trying to improve driveability). When I was reviewing them in the living room I noticed the last two data logs had O2's at a CONSTANT 11.81. The first 4 logs were normal. I just went out to the car to see what it reads now. Now it's 0.00 and won't move. Has my WBO2 gone tits up? I've NEVER run racing gas across it. This is the first problem I've noticed with it. Is there anything else to look at? H E L P!!!

The other wierd thing is that it doesn't try to correct the O2's at all for this condition either. O2 corrections register 0 the whole time.


Derrick

 

[Hyper]

GN1R Ported/Polished Heads

that is what is doing it, you have to much head. Box them up and send them to me. I will send you some stock ones for them....................................................................................................................................................................................................................................LOL.......................................................................

 

[aDFIguy]

Can you log the actual voltage on the O2 input to the ECM? If not, you may want to try probing the pins on the header of the ECM with a voltmeter.

 

[Craig Smith]

There is no "voltage input" to the ECU that you can measure but there are a few things you can check.

First and foremost, make sure the lambda symbol with the letters "WB" appear on your C-Com screen. This verifies that the O2 is connected and the ECU knows it. If this symbol is not there nothing will work.

Second, while the car is running, check a voltage in the main dash display called UEGOS. It should stabilize at about 0.45 volt with the car running. From what you are describing I do not anticipate that you will see this right now.

After this, unplug the sensor from the ECU. Check the following voltages with the ECU online, car off, and the sensor unplugged:

UEGO (should be about 3.5 volts)
UEGOS (1.02 to 1.04 volts typically)
UEGOR (should be 4.98 to 5.00 volts)

A visual inspection of the sensor and the wiring leading to it would be a good idea as well. Let me know what you find.

 

[tazgn]

I went out and tried it a third time last night and all of a sudden it worked. I have no idea why. If it happens again I will check all of these things. I forgot all about the lamda symbol. That probably would have helped diagnosing it yesterday. Hopefully it will all work fine now on. Thanks for the help.

Derrick