Can anyone tell me if I should see continuity from my 02 sensor harness
plug between the signal pin and the ground pin?  I was just testing that
and I get nothing from the plug....but.....if I probe the signal pin and
ground to the block, I get continuity...Can that mean that my problem might
lie in the ground pin of the harness plug from the sensor to the ECU?

  If I touch the ground pin and the block...nada, nothing.  If I probe any
of the other pins and the block...I also get a signal of continuity.

On Thu, Jul 24, 2014 at 6:59 AM, Don Hanson <dhanson928@gmail.com> wrote:

>    This is an inline VW motor but running all the electronics, same as and
> probably directly from, a Digifant Vanagon...started with an 84 van...now
> has a 92  Jetta 1.8 liter 8 valve motor in that van with the diesel motor
> mounts but it is a gas motor..
>
>    I am almost sure I have the problem isolated to the 02 sensor..The
> engine runs OK with that disconnected, plug it back in and after a few
> seconds, the engine goes full rich and smells like unburned fuel from the
> exhaust.
>
>    Just about a week ago I replaced the old O2 sensor with a new Denso one
> and it ran perfectly for about 500 miles of highway driving, until
> yesterday when it began stumbling and losing power.   If I switched off and
> back on (ignition) it cleared up for a few seconds...so I made it home that
> way and I have been working on finding the cause.  I have had some great
> help so far, but I am still not sure exactly where the problem is...The
> wires leading to and from the old O2 sensor were brittle and cracked.   I
> spliced in the new one, but the harness from the plug to the ECU, that also
> had some insulation cracking and brittle wires...Those I have also patched
> up for now, I will try to find another 'pig tail' to replace that later,
> but for now I am trying just to isolate the problem so I can get the proper
> fix done.
>
>    Now here is where I am in this process...I have the O2 sensor out
> again, on my bench.   I have access to the plug back into the harness.
>
>    I want to bench test the 02 sensor, which I am told can sometimes be
> bad even though it is almost new...I am told there is a way to put a
> propane torch on it and get a reading from my voltmeter, but could someone
> outline this test procedure so an electrical dunce can do it?
>
>     I am also told I should have continuity between the signal wire and
> the ground wire from the ECU harness....I don't see that, ignition on or
> off...When I put my voltmeter probes on the plug back to the ECU, the one
> that accepts the plug from the O2 sensor, and I turn the ohm meter to the
> 20k scale, I see no movement at all from the digital readout....When I
> probe the two heater terminals, I do see continuity...
>
>    Where the signal and ground wire enters that shielded casing, there was
> some frayed wires that could have been contacting the metalic shielding...I
> trimmed that back a bit till I have clean wires and I have repaired the
> fraying.   So should I have continuity between the two terminals there at
> the O2 plug back to the ECU, or am I totally off base here?
>
>    OK another thing I changed was my Temp II sender....I have not tried
> adding that into the diagnostic process yet...Should I?   I have been
> assuming that since the engine runs clean with the O2 sensor unplugged, or
> after I cycle the ignition off, that the problem must be in the O2 sensor
> circuit...Should I put the O2 sensor back in and try un plugging the temp 2
> sender?...I have some spares that I can substitute also...
>
>    Any advice would be greatly appreciated... and thanks in advance
>
>   Don Hanson
>