purgoose10
Veteran Expediter
The ScanGauge isn't accurate insofar as MPG, and they'll tell you so (in the manual). I'm not sure about the original model, but the ScanGauge II has a plus/minus thing when you go to MORE|FILLUP and tell it you just filled the tank. It will tell you how much it thinks you should have put in there, and if you put more or less in there you can do the plus/minus thing to increase or decrease the percentage it uses to calculate the fuel consumption. After a while, with enough tweaking, it can become somewhat accurate.
If you have a Espar heater (or a refer, for that matter), you'll need to tweak the percentages in the winter to account for the fuel used by the Espar (although it's almost small enough to not even worry about).
What I do is take the total miles driven for the year (or month or whatever), and divide that by the total amount of fuel put into the vehicle. That gives me the most accurate fuel economy for the fuel I've consumed, be it running down the road, idling or with the Espar heater. I also check it fill-to-fill, especially on long loads, just to keep an eye on things, to make sure I don't have a sudden major drop in fuel consumption.
I can generally look down at the fuel gauge and know within a few miles how many miles I have remaining. Although, I really pushed that the other day when, in zero degree weather, I put 27.363 gallons into a 26.5 gallon tank.
I mostly use the ScanGauge II to monitor coolant temp, voltage, current MPG (the one that changes rapidly) and for MPH since the Sprinter's odometer is off by 3-5 MPH depending on speed.
I also use the scan gauge but the problem is fuel mileage with a diesel. For some reason it doesn't keep good miles but keep all the other data. I would also like to be able to clear the scan gauge after I use it but you can't on this model.