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rick-l rick-l is offline
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Join Date: May 2002
Location: St Louis
Posts: 4,211
Quote:
Originally posted by cgarr
If you unplug it, take a volt reading from it when hot, I think if your mixture is correct it should read somewhere from .4 to .8 volts?
Craig
that's not the way it works. The oxygen sensor puts out about 2 volts when it is in a rich (no oxygen) environment and < .5 when it is in a lean environment (not enough fuel to react with all the oxygen). The output is a step (very steep slope) between rich and lean. The computer tries to maintain optimal (lambda) by switching the mixture between rich and lean.

This is called a bang bang control system, kind of like the thermostat in your house. Too cold, add heat (turn on furnace). Too hot turn it off. Do this fast enough and you maintain a reasonably steady temperature.

If you have a high impedance voltmeter you should be able to monitor the sensor output (+ lead on the sensor - to ground) and see it switch but I have never done so.
Old 07-11-2005, 09:39 AM
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