Chuck
Yes, any O2 sensor has a working range of about 0.1 - 1.0 volt.
Except some of the newer Hondas.
I understand they are using a " wide band " O2 sensor ( 0.1 - 5.0 volt ).
If you are running with only the " signal " wire connected ( heater element power & ground not connected ), there is a good chance the sensor will cool off ( below 600 deg. ), in which case the ECU may even go back into open loop.
Open loop usually means a slightly richer running engine, which may explain a slight smell.
You can verify this theory by running the engine at @ 2000 rpm for a couple of minutes, and then check your signal.
It should show varying voltage as long as the O2 is still hot.
