Calculating mpg from Elanscan/ecu data

[mnemonix]

Hypothetically... if I wanted to calculate my miles per gallon from the data provided from the ecu, what would be the best approach for determining fuel use? Air/Fuel ratio and cylinder displacement ? Injector duty cycle & pulse width ? Some other route ? or is the data not accurate enough to derive a usable mpg from ?

I'm toying with ideas for plug in trip module that might display useful data, though in the first instance it could be done with an excel spreadsheet export from Elanscan.

Chris.

[GeoffSmith]

I believe my Scirocco used injector pulse width, engine speed and road speed - it was reasonably accurate.