Just joined 02-22-2017. Bought vehicle 02-11-2017. First fuel up by dealer was at 70 Miles. I did not record gallons required. Only have 370 miles on vehicle as of 02-22-2017 and have not filed up.
I entered the dealer Fuel UP as estimated gallons (2.0). I put in 70 miles on odometer so, the used miles would show up on next fill up for accurate calculation of MPG. However, that reading does not show up in table????
One question: Is there a method to subtract miles on car when Dealer filled it?
Otherwise, the next fill up at Miles would include extra miles (70 miles in my case as that is when the dealer filed it and I did not write that down), so the mile per gallon would be in error if you used the total miles on vehicle at time you filled it the first time.
I just let it run until needed gas. Also made a mistake on initial fill up by dealer (actually I pumped gas, dealer paid for it) - it was at 65 mile that I wrote in my Log Book indicated instead of 70 miles I thought I remembered.
So, filed up today (02-27-2017) at 534 miles with 9.11 gallon. 469 miles divided by 9.11 gallon = 51.48MPG.
Computer had been showing from I think I remember a range of 53 to 55 MPG during this time. Nearly all that miles was in a range less than 50MPH and on county roads (some in town where we have a few stop and go situation).
Can't call it City, but for sure not HWY at 50 to 70MPH.
Big Variable on one purchase of 9.11 gallon is how close was tank filled to the same level. ???? Take a few thousand miles to have a decent average MPG.
Consistent filling is important, what's not important is the level you decide to fill up at. Could be a quarter tank, half a tank or even refill after 50 miles, it matters not, so long as you brim the tank.
The only way to make it consistent is to either wait until the pump cuts out from feedback, or do what I do and fill it until you can see fuel at the nozzle, so you know you physically cant get any more in.
Filling it until you see fuel is the surer way of getting consistent fills, but it risks damage to the evaporative emission system on the tank, and could be time better spent elsewhere.
Easiest way is to just fill to one or two click offs; choose one and stick to it. Trying to use the same station and pump will also help with consistency, but over a car's lifetime, deviations in fills will average out for our purposes.
Another thing to note, is that distance related stats such as "average miles per tank" or "distance driven last month" will be thrown off by fuel ups with no mileage input. Your average miles per tank is now 200 and something as your other fuel up has been divided by two.
My favorite station has a drainage depression in the pavement where I can get the front of my car a few inches lower than the rear. With the fuel tank located under the back seat and the filler neck about 3 feet long, this allows for very consistent refills.
On my old Civic VX the issue of inconsistent fills was even worse. Drive a couple of miles, then top off the tank and end up adding another gallon or more. To get this issue resolved, I took a 6 inch piece of a 2x4 an drove the left rear tire (filler neck at the left rear) up on the piece of wood at the pump before filling. In fuel tanks where the filler neck goes into the side of the tank, this practically eliminated short fills.