On Wed, 13 Feb 2002, jhlauterbach wrote:

> Last weekend, I got the old Heathkit VTVM (high impedance analog voltmeter)
> out and put one probe on the spade lug at the end of the sensor cable and
> the other problem on the A/C compressor.  I got about +0.47 volts with a
> very steady reading.  Engine was fully warmed up and idling about 1000 rpm.
> Ambient air temp was about 65 deg. F.
>
> Do I need a new O2 sensor?
>
> John Lauterbach
> Macon, GA
> '84 7-passenger
>

If the ECU was not connected to the sensor also, it probably did not
realize that the engine was warm, so the test was inclusive.  It is
encouraging that the sensor produced a reasonable voltage.  If you try it
again with the connection to the ECU complete, you should be able to see
the voltage bounce up and down once the ECU goes into closed loop control.

I once had a Heathkit meter like that.  Built it in 1971.  Wish I still
had it, just for this job.

Larry A.