ShadowsPapa
Well-Known Member
- First Name
- Bill
- Joined
- Oct 12, 2019
- Threads
- 180
- Messages
- 29,520
- Reaction score
- 35,123
- Location
- Runnells, Iowa
- Vehicle(s)
- '22 JTO, '23 JLU, '82 SX4, '73 P. Cardin Javelin
- Occupation
- Retired auto mechanic, frmr gov't ntwrk security admin
- Vehicle Showcase
- 3
No. Not for me, anyway.
It seems about every other fill the dash is higher than when I calculate it using the FillUp app. And in the times it's not higher, the app result is higher.
That's because the vehicle is measuring things not based on how many gallons did you squeeze into it this time but by other factors.
If you fill it and put in, say, 18 gallons then drive the exact same route in the same way and come back and stop at a different pump on a different day facing a different direction, you won't get in those same 18 gallons again. Temperature of the gas in your tank matters, how level is your truck matters, exactly when did the pump "click off" matters, among other things.
So calculating at the pump will almost always be different. If I go to the same station but stop at a different pump, my truck may be leaning .5 degrees to the right this time where it was sitting perfectly level last time. Did I get the gas in the tank to the exact same level as last time? Did I put a stick into the tank and see that it's exactly the same amount (no, of course)
Other factors that may make the dash calculations different - did you change tires? Have you verified your odometer is precisely measuring by comparing to an independent GPS?
I did - I used a Garmin GPS and an app on my phone. I set everything to 0 and reset my trip counter on the truck. I then drove over 17 miles and watched my truck's speedometer and the speed on the Garmin and on my phone. They were exactly the same. When the truck's digital display said 55 so did the Garmin and my phone app. As I varied speed I watched and they followed each other right on the money.
When I got home I compared the miles traveled on the truck to the Garmin GPS and to my phone. They were exactly the same to the tenth of a mile.
People often swap tires and plug in the number they are told to plug in and assume it's 100% correct. I do the "trust but verify" thing - I put in a number I trust to be right - or close, and then I measure like above - if there's any difference, I change the tire diameter in the settings and try again until everything is right - and mine is right.
So in short - I find that sometimes my cluster MPG is a tenth or two higher than what the FillUp app says, and sometimes it's a tenth or two lower than what the phone app tells me.
I expect that - but I'd bet if I tracked over a year's time, the results would line up pretty darned close because I can never fill my truck the exact same way two times in a row.
The gas you put in your truck starts out at about 55 degrees - a couple of days in the TX sun and it's a degree or 40 warmer, so it expands. Drive to Iowa and it will be 20 degrees after a few hours.
That alone makes a difference on how much gas you get in.
Sponsored
- I do use mine as a DD most of the time and am pretty happy. It could be better but the drops in mpg are purely my own doing and fault.(tires, steel bumper, lifted about an inch, etc.)
