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I read somewhere you can test your O2 sensor by running your car once warm,

maintain the engine rev's at 2000rpm (car not moving), and going by the LED on the back of the

ECU, whether it flashs or doesn't flash you can work out how lean or rich its running.

Has anyone actually performed this test?

I'm about to, just wondering whether i'm wasting my time or not.

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Yes its a very good test. You basically are counting how many transitions its making (ie flashes). I believe it has to be at least 8 times every 10 seconds. As O2 sensors age, they get slower and the transition times are longer.

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If it doesnt flash at all its either dead or you are not in the correct diagnostic mode. If its erratic... well you have to explain exactly how it flashes. Its not going to be blinking at a completely steady rate but it should pulse once or twice per second.

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After disconnecting the O2 sensor, my car ran so much better.

I re-connected it and performed the test.

While holding and idle of 2000rpm i watched the light on the ECU.

It flashed maybe twice in 10 seconds. On average mine seemed to flash every 8-10 seconds. Going by this my O2 sensor is causing the car to run really rich.

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the sensor for the r33 is about $120

just go buy a new one if you are in doubt

the time youve wasted on fuel and mucking around

you could have started saving already :0

chances are youve still got the stock 02 sensor in there

and it shouldnt affect how the car "runs".

ie: there should be no reason whatsoever it will come on boost better, go harder, drive friendly or anything. any changes you are noticing won't be the 02 sensor

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  • 6 months later...
I read somewhere you can test your O2 sensor by running your car once warm,

maintain the engine rev's at 2000rpm (car not moving), and going by the LED on the back of the

ECU, whether it flashs or doesn't flash you can work out how lean or rich its running.

Does this test work on R33's?

How do you enter "diagnostic" mode to see the LED flash???

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the sensor for the r33 is about $120

just go buy a new one if you are in doubt

the time youve wasted on fuel and mucking around

you could have started saving already :0

chances are youve still got the stock 02 sensor in there

and it shouldnt affect how the car "runs".

ie: there should be no reason whatsoever it will come on boost better, go harder, drive friendly or anything. any changes you are noticing won't be the 02 sensor

I replaced my O2 sensor a little while ago due to excessive fuel usage (thought I would give it a go). Fuel usage did not get any better so I assume the old one was probably fine too, but I have noticed on the PFC that my O2 sensor voltage jumps around wildly and seemingly randomly. It does seem to pretty much stay on 0.0V when the engine braking though. Otherwsie its anywhere from 0-1V. Is this normal?

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It is normal for the voltage to jump around and it should be the case. Only faulty O2 sensor will stay @ 0.3v constant. Otherwise, it should jump around 0.6v to 1v @ 2000rpm (crusing speed). Other way to test it is to measure the resistance (but it is only a crude test). Unplug the terminal of the O2 sensor, there should be 3 pins in the O2 terminal. Measure the resistance between the 1st and 3rd pin. It should read about 2.6 +- 2 ohms. Anything outside that indicate O2 faulty. PLEASE NOTE THAT THIS IS A VERY CRUDE TEST. ONE SHOULD MEASURE THE VOLTAGE OF THE O2 AT 2000RPM FOR A BETTER INDICATION.

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