Oxygen Sensors and junkyards

[Alain Toussaint]

LotusM50 at aol.com wrote:
> 
> In a message dated 97-05-20 03:55:14 EDT, tboicey at brit.ca (Trevor Boicey)
> writes:
> 
> << Can somebody please provide me a brief rundown on the
>  types of Oxygen Sensors? I forget the name of the device
>  I am referring to, but I mean the simple type that can
>  be used to give rough lambda readings and can provide
>  feedback to closed loop systems.
> 
>    I know there are heated and non heated, and apparently
>  they are known by the number of wires which each has. I
>  suspect the "more wire" types are heated, but I want to be
>  sure before I start spouting inferred facts. >>
> 
> On a similar note, the Electromotive system (no flames please) uses a 4 wire
> heated oxygen sensor.  Does anyone know from what car Electromotive sources
> this part from so I can get one at my local parts store.  I would prefer not
> to pay Electromotive's price.  Also why 4 wires?  What does the 4th wire do?
> 
> -Bonni suppose that the 4th wire is used for troubleshooting !!
correct me if i'm wrong !!!
Alain