I just replaced the O2 sensor on my van with a bosch replacement from autozone. The old sensor was intermittant. When the old sensor was working, I would measure about .4 volts with the engine at normal temperature. This new sensor starts out at .5 volts cold, climbs towards 1 volt, and then begins to flip flop between .2 and .9 volts at about a one second rate. Is this normal? BTW, it's a 1992 5.2L. Tia
O2 sensor
Sep 18, 2007
3 Replies
Yes, that's normal.
Right - that still wasn't working correctly. O2 sensors, when running properly, constantly fluctuate between rich and lean, constantly trying to keep the engine at 14.7:1 A/F ratio.
That's the way they're supposed to work.
I expected that the fluctuation would be rather fast so that a moving coil meter would average it out to somewhere between .4 and .6. It does seem to run OK, Thanks to all bg
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