a/f ratio with LPG

[Darrell Norquay]

At 01:31 PM 5/16/96 +1000, you wrote:
>Hi everyone,
>
>I was wondering if it is possible to use a normal (i.e petrol) O2 sensor 
>when running a car on LPG, as opposed to unleaded fuel.
>
>Thanks in advance,
>
>		Bruno.  (u933234 at student.canberra.edu.au)
>

I've been running O2 sensors in my Camaro on LPG for a year or so now,
but I'm still not sure they read back any useful info.  The Stoich A/F ratio
for propane is around 23:1, and although Stoich is Stoich no matter what the 
fuel (at least in theory), they seem to read lean most of the time.  I'm 
reasonably certain that my mixture is not as lean as indicated, but I have the
sensors mounted in the header collectors which is fairly far from the engine,
so it may be a problem with location rather than the sensor itself.  I want
to try some heated sensors to see what difference it makes, I'll let you know
what happens.  By the way, O2 sensors do read oxygen content, at least in
that they are proportional to the difference between the exhaust O2
concentration and the ambient air.  They are unaffected by concentrations of
other gases, and generate a voltage by pumping O2 across an electrochemical
cell.

Regards
dn