I've been reading alot of posts during the tuning of my prom, and somewhere I read that the "perfect" air/fuel ratio would have a .450 mV reading, now from that I would think that would mean from the O2 sensor volts. But I see there is a field on my DataMaster scan tool called "Fuel Air Value", and it sits usually around 440-470, does say mV or any units value, is this what alot of posts are referring to when the .450 is mentioned because from the O2's perspective I would have thought the around .750-.800 mV would be desirable.
Thanks

 

This question (stock O2 sensor) is so frequently asked, it should be an FAQ.....

Don't use the stock O2 sensor for tuning. It is designed to run 14.7:1 (stoich) as a switching device around .450 volts. It was never intended (nor should it be relied upon) as a tuning aid. It rapidly becomes inaccurate above .75 and below .25 Volts. And the closer you come to 0 or 1.0 volts the more inaccurate it is.

If you want to tune for WOT, get a WB O2, do plug cuts and performance measurements (1/4 mile being the best).

 

Well I'm not really looking at it from a WOT perspective currently but will be soon, but while on the subject of the WB O2, are they a direct replacement to the 3-wire heated sensor for a '92 TPI? Did the f-bodies originally have a 3-wire or single wire O2? This is on my truck that was originally converted from TBI to TPI is why I ask and it had a 3-wire heated O2 thats in use now.
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Is the "Fuel-Air Value" field in DataMaster what I should be paying attention to?
Thanks