pensioner wrote:

> Hmmm...just how does the sensor sniff the ambient air?  WRT ambient air vs
> O2 in exhaust note.
>
> I seem to recall the Lamda sensor is a voltage generating device whose
> output varies proportionally to the amount of oxygen in it's immediate
> vicinity.  <1mm from the surface.
>
> Or it could just all be a guess.  I've never actually seen an electron, have
> you?
>
> pensioner (sorry I missed friday)

The Bosch manual  (p.22) shows a cutaway view of a sensor.  There is a vent
opening at the back near the wire which lets air in, so that the hollow sensing
tip is exposed to ambient air at its inside surface and the exhaust at its
outside surface.

Bosch Fuel Injection & Engine Management
  Charles O. Probst,  SAE

ISBN 0-8376-0300-5
Bentley Stock No. GFIB
'91 edition

Should still be in print. Highly recommended (by me anyway).

Larry A.
Chicago