Here is a software for OBDII to do what you are talking about.
http://obdiitools.gdatabase.com/

I just do the old fashon way. When I pump gas I reset my milage or
write down the current milage and pump the tank full. That way next
time I pump I record that amount and divid it into the milage recorded
and get an average MPG.


Regards,


BennyB
TeGGeR® wrote:
> "Chris" <criro1999@gmail.com> wrote in news:1160064779.892720.143910
> @i3g2000cwc.googlegroups.com:
>
> > Is there any way (formula) to calculate the fuel consumption (e.g.
> > L/100 KM or Gal/Mil) from values read from OBD-II interface?
> >
> > I think next values could be taken into consideration to compute the
> > fuel consumption, but I don't know how exactly to interpret the result
> > of them:
> >
> > Short Term Fuel Trim
> > Long Term Fuel Trim
> > Mass Air Flow
> > Fuel Pressure
> > Accelerator Pedal Position
> > Throttle Position
> > RPM
> >
>
>
>
> I seem to recall seeing a laptop-based OBD-II diag system that was capable
> of the sort of number-crunching you need to do. I don't seem to have
> recorded the maker, though.
>
> Laptop solutions are software-based, with an adapter cable that conects the
> OBD-II DLC port and a USB port on your laptop.
>
> --
> TeGGeR®
>
> The Unofficial Honda/Acura FAQ
> www.tegger.com/hondafaq/