Dashboard MPG readings may be off

[mettech]

Edmunds.com, like the automakers, periodically tests the miles-per-gallon readouts on new models, with varying results.

For instance, in 2010, the website tested a Ford Escape Hybrid — a vehicle that no longer exists — and found the mpg readouts overstated fuel efficiency by as much as 19 percent. The 2010 Volkswagen Jetta SportWagen TDI dashboard readout was optimistic, too: by 16 percent. That meant drivers thought they were getting better fuel efficiency than they actually were.

The 2014 Chevrolet Silverado, Dan Edmunds said, was about 2 percent optimistic, based on data from approximately 20 fuel tank fill-ups.

Most cars overstate by about 5 percent. And while that’s insignificant for one fill-up, it could be off by hundreds — and possibly thousands — of dollars over the life of a vehicle.

Readouts use variables

The reason that mpg readouts are inaccurate is that vehicles aren’t actually measuring fuel consumption, but instead an algorithm based on variables such as engine revolutionsper minute, gear, vehicle weight load and throttle angle.

In other words, the readouts are estimates, and often calculate fuel efficiency based on optimal vehicle conditions, such as properly inflated tires.

From The Detroit News: http://www.detroitnews.com/article/20130914/AUTO01/309140030#ixzz2ey0AnuS7

[SoonerLS]

My LS and F150 both have MPG readouts, and are both off, but they both read low.

[RichardJensen]

In other news:

 

Estimated fuel economy is estimated.

[EBFlex]

Edmunds.com, like the automakers, periodically tests the miles-per-gallon readouts on new models, with varying results.

For instance, in 2010, the website tested a Ford Escape Hybrid — a vehicle that no longer exists — and found the mpg readouts overstated fuel efficiency by as much as 19 percent.

 

Huh.....imagine that. I bet a software reprogram could fix that.

 

1/5

[ANTAUS]

I gave up on even looking much at the LS-readout. Usually 12-14MPG is what I averaged which is hilarious. And few times in the highway on my road trip to the beach maybe 17-18MPG at 90-95MPH. I just cycle so the screen just showed me "Miles to empty". The MKX does much better around town at 16-18MPG, but always thought the readout what lower than what it actually is. Or maybe they do not account for the "reserve" gallon of the gas tank?

[fordmantpw]

Our Flex is pretty close, but my truck usually reads 1MPG +/- higher than actual.

[Noah Harbinger]

My C-Max extremely consistently claims that it has used 3-4% less fuel (according to the trip meter) than the gas pump claims to have dispensed. This has been consistent at pumps from 4 different stations so far. (Only 7 fill-ups though).

Edited September 25, 2013 by Noah Harbinger

[Hoser768]

When I reset the fuel meter at fill, and use the same pump, my Five Hundred has never been more than .1 gallon off when I fill the tank.

Fill, reset fuel usage, drive some miles.

 

Check gallons used on gauge. If the computer says I burned 17.0 gallons, I'm going to pump between 16.9 and 17.1 gallons in.

[Deanh]

I have an ultagauge, based on MPGS calculated at fillups, its a lot more accurate than the dash display, dash reads 33.3 ave, Ultragauge 36.7. Also, when my light comes on at 50 miles to empty, when it gets to empty I rarely put anymore than 10 gallons in the car yet the tank is 12.2.....

[NickF1011]

The MKX does much better around town at 16-18MPG

Eek. My Edge Sport's readout is typically in the 21-22 MPG range!