MicroSquirt.com read only forum (Jan.15,2018)

Is there a way to measure fuel consumption with MSII and Megatune 225 rather than waiting till I've run through a tank of gas and seeing how much it takes to refill it while recording the miles? It doesn't have to give me an accurate MPG estimate to show me what tweaks and driving style changes help and what hurts. Would the "Duty cycle" gauge the earlier versions of Megatune work?

I could run datalog while driving a 3 mile loop, make changes and make another datalog driving the same loop and the use a spreadsheet to add all the injector pulse widths up from each datalog to see which had the injector open more. It wouldn't account for fuel pressure changes due to the manifold vac applied to the pressure regulator, so I don't know how accurate it would be. The most accurate I can think of would be to run an extra injector that shoots fuel into a graduated cylinder.

Can anyone recommend a good way?
Thanks!

Joffrey,

Yes, you can add up all the injector pulse widths (and subtract the opening times). You would have to edit the code to do this (it wouldn't be too hard) and you would lose the value when you powered down, so you wouod probably have to be datalogging.

The intake manifold vaccum applied to the fuel pressure regulator ensures that a given amount of pulse width injects the same amount of fuel regardless of the intake manifold vacuum (because the pressure differential across the injector is the constant), so it doesn't come into the calculation.

Lance.