When disconnected, failed, removed, cut wires, whatever, the ECU goes to
open loop and the engine will run rich. This is ok for a short while,
BUT, your emissions go way up, and you will get a carbon build up
started in your CAT and Muffler that will do it no good. Reducing the
life of same. How much is anybody's guess, but it will happen.

I like GM Bulleys testing method. Throw it in the lake. . If it floats,
clean with carb cleaner and re-use. If it sinks, get a new one. The
generic ones are cheap enough and keeping a good one in the engine is
good for the engine.

John Rodgers
88 GL Driver

David Beierl wrote:

> At 12:44 AM 1/14/2003, Claudio Cella wrote:
>
>> Hello to all, while on the topic of O2 sensors:  if i understand
>> correctly
>> if the sensor shows no volts (bad sensor or no sensor)ecu defaults to
>> open
>> loop which means running rich.  Is there a way to run without the O2
>> sensor
>> and trick the ECU into running lean?
>
>
> No, if the sensor is open the ECU will bias it to very close to 500
> millivolts.  A sensor reading 0 volts (from grounding or whatever reason)
> will cause the ECU to richen the mixture until the ECU runs out of
> adjustment room, and your mileage will go down to about 10 mpg (whatever
> that is in l/100 km -- anyway, it will drop by close to half).
>
> To run without the sensor, just unplug it.  The ECU will go open-loop and
> if AFM etc. are correct it will run fine, but emissions will go way
> up.  If
> AFM is off it will run too rich or too lean.
>
> d
>
>
> --
> David Beierl - Providence RI USA --
> http://pws.prserv.net/synergy/Vanagon/
> '84 Westy "Dutiful Passage"
> '85 GL "Poor Relation"
>