Can't fill tank up to rated 15.8g capacity and miles to empty range vs actual miles driven problem!??

DSH93 · Nov 8, 2020

Hello,
I can't fill the g70 tank to more than 14.8 gallons when tank is empty. Always one gallon short. I have the 3.3t AWD sport. Tank rated at 15.8 My miles until empty range when full is 318. Getting 21 miles per gallon with all city driving in comfort and occasionally sport mode. Is this normal tank capacity when filling this vehicle? Also, miles to empty range is going down faster than miles driven while getting better mpg in city than rated by manufacturer according to digital calculation on dash. I Drove 105 miles and lost 120 miles of range should I be concerned? I'm thinking I might have a fuel sending unit problem. A couple weeks ago, I unfortunately drove open a rock that was stupidly placed in parking lot and it hit under my left back tire by gas tank heard a bump by no scrapping and took it in to dealer. Dealer said no damage on undercarriage and no problems with few lines or anything. I don't know if I can trust them. G70 is less than 1500 miles on it. Please help me.

Thank you

joschneider · Nov 12, 2020

You’re fine. All normal. Fuel range in the display is always recalculating as you drive

Mr. Incredible · Nov 12, 2020

is your tank 100% dry and you had to push the car to the station?

all vehicles are built with a 2 gallon reserve capacity per federal regulations (some are higher, but not lower). so the 15.8 size includes the reserve, when the low fuel light comes on you have 2 gallons before 100% dry, but even then you will never get 100% dry because the fuel pump pickups don't sit at the bottom of the tank, they are usually a few mm higher so they don't pick up the sediment that settles at the base of the tank.

G80 has a 20.3 gallon tank size, I rarely am able to put more than 17.7 gallons at fill because I typically fill within a mile or 2 of the low fuel warning.

and the range calculation is a guide, it is not 100% accurate, it changes based on driving habits, stop and go, uphill, downhill, etc.

mine always says 435-455 at fill, I rarely see more than 360, though I did do a 460 mile round trip this past month on a single tank, cruise set at 70mph and it took 18.9 gallons at fill, the average was ~24mpg on the computer and manual calculation, but the mile to empty told me I had zero miles to empty and I went another 28 miles before I got to a gas station.

Fantine56 · Mar 1, 2021

My 2021 G70, showing an average of 25 mpg, has a range of 351 after being filled up. I find that hard to reconcile with a 15.8 gallon fuel tank. My dad's 2021 Sonata Limited, which is supposed to have a fuel tank only slightly larger at 15.9, has a range of 451 when filled. This doesn't make any sense. The Sonata's fuel tank should be closer to 18, right?

Mr. Incredible · Mar 1, 2021

Fantine56 said:
My 2021 G70, showing an average of 25 mpg, has a range of 351 after being filled up. I find that hard to reconcile with a 15.8 gallon fuel tank. My dad's 2021 Sonata Limited, which is supposed to have a fuel tank only slightly larger at 15.9, has a range of 451 when filled. This doesn't make any sense. The Sonata's fuel tank should be closer to 18, right?

all has to do with driving style.

my G80 would show anywhere from 360 - 460 mile range when filling. example. commute to and from work all stop and go most of the time the range showed 360 @ fill and the low fuel light came on around 320 miles.

I drove cross country twice since 2018, hours at 65-70 mph on the highway, range would show 450-460 at a fill and low fuel light came on around 420 miles.

in both cases if I filled within a few miles of the light, the car only took 17.5-18 gallons of a 20 gallon tank, meaning it had 2ish gallons in reserve when the light comes on (federal mandate for 2+ gallon reserve)

the difference here is the driving style, commuting 19-20mpg vs. cross country 25-26mpg, the calculation adjusts based on the accumulated mpg from that last reset of the accumulated screen, if you have yours set to reset at fill up then it is per tank.

my Palisade is exactly the same, 400 mile drive from AZ to CA and the range estimated 490 miles, now I am in town and commuting the range estimate has dropped to 360, 27mpg on the 400 mile drive vs. 19mpg commuting.