# o2 sensor madness



## Pingu (May 22, 2003)

Something is up with the o2 sensor and/or crossed wires.

I bought the car a while ago private sale. 
Either the o2 sensor has had it. And/or wires are crossed.

I under stand the sensor reading is only "accepted" by the computer when it fluctuates around 450 mV , and then it controls only idle & cruise in its closed loop form

This is what ive found and im stuck for what to do now as replacing the sensor might not help.

I'll describe it the way i see it as im not even sure which wire is which anymore.

When ignition is switched on but no engine running the wires (further up than the sensor wire connector) read:
Left 11.9 volts Middle 0 Right 0

When engine is running idle & higher rpm while warm:
Left .82-.84 Middle 0 Right 13.4+

If i had it say up to 2500 rpm and let go of the throttle cable Left wire on spool down only of engine spikes to 12 volts (then dies back down to .82) after reving it up then closing the throttle valve instantly. The others in this situation. No change.

When i disconnected the sensor from the upper wires and took a reading of the sensors wires while the engine was still running without the sensor.
Left 0 Middle sat around .25-.40, but some times read 0 consistantly. Right 0

Maybe the connectors have been wired incorrectly ,maybe wires crossed.

When reading upper wires while sensor is disconnected and engine is still running.
Left .62 Middle 0 Right 13.4

Why is there a reading on that upper LH wire while the sensor is dissconected!?!?

Earlier i was sure that the left upper wire was signal output of the sensor as it read a sub 1v. And the others were heater. 

Can any of you guys shed some light on this!?

Thanks
Andrew


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## Pingu (May 22, 2003)

Ok ignore that ill upload a picture of the situation and put a url link on here


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