How accurate is a Scangauge 2 for MPG?

[jamesqf]

Originally Posted by JockoT

But which one is right?

The Insight's built-in gauge tracks actual mpg calculated from fillups & distance pretty closely, and miles by odometer is as accurate as I can measure. And what it displays seems reasonable, vs the SG's sometimes wildly unreasonable values. As (IIRC here) showing 100 mpg going up a hill where the Insight shows 50, then showing 50 down the other side where the Insight's display is pegged at 150, and the SG is showing it's in DFCO.

PS: I do have an SG that dates from about 2004 or so, soon after I got the car. Recent versions could do a better job. And my examples are from memory of the first year or so - I haven't used the mpg stuff since.

[JockoT]

When you fill up do you tell the Insight how much fuel it took to fill the tank? My Citroen van, you just tell it you have filled up, not how much. With the ScanGauge you actually tell it how many gallons you put in (or should do). I have yet to run the ScanGauge for long enough to do a second fill up, but I am looking forward to seeing how accurate it is once I get to a third and subsequent top ups.
I must admit though, your figures for up and down hills seem wrong. There is a setting in the setup to correct DFCO errors.

[jamesqf]

Originally Posted by JockoT

There is a setting in the setup to correct DFCO errors.

Not in mine, as least as far as I remember. But as I said, mine's more than 10 years old, so newer ones might have more features.

[JockoT]

This is the part from my manual.