"Dave S" wrote in message ink.net...

Ok.. here's how it was explained to me, including stuff in the past few days.. I am not speaking authoritatively, only
repeating from a collage of sources i've come across in the past 3 years.

................snip A 5 wire sensor incorporates a nonconsumable oxgyen generator of some type, in addition to the
heating elemet. I do not know how its generated, but a mixture monitor or EFI that is able to offset the oxygen reading
with the oxygen generation value can be used as a wide band oxygen sensor and can give a wide range of air fuel
mixture indications. This can reportedly be used to indicate optimum mixture for lean of peak ops.

An EGT being used in a closed loop EFI situation must respond nearly instantaneously.. in milliseconds. Being used in
leaded fuel will quickly render the sensor unuseable in this setting, for this cause.
However, even when the sensor degrades to perhaps 1/2 a second lag time, this is still quicker than you can adjust the
mixture manually, so even in a leaded fuel situation, you can get a lot of life out of an oxygen sensor.

One of the folks in the Rotary engine crowd has reported getting 85 hours out of an ordinary 1 wire oxy sensor with
nothin but 100ll. Running auto gas can sometimes undo the lead fouling to the point the sensor remains viable over its
normal service life.

1 wire oxy sensors are cheap as far as aviation prices go. Changing it every 50 hours with your oil filter wouldnt be
out of reason.



Interesting post...thanks...