> when you disconnect the O2, sensor I figure the voltage output goes to
> zero.
> How does the Fuel injection treat this output?

ECU defaults on O2 open loop to a sort of "safe" mode, usually running the
engine slightly on the rich side. Not terribly fuel efficient and it
probably would never pass a smog test, but it runs in a satisfactory manner.
I'm sure "open loop" mode on the Vanagon ECU compares unfavorably with the
same vintage euro-spec Digifant, which had no O2 sensor input; but in any
case, the Digifant is perfectly capable of running sans O2 sensor.

--
John Bange
'90 Vanagon - "Geldsauger"