Question RE ethynol blend and my computerized gas gauge

[doni_georgia]

I have recently switched to ethynol blend in my car (finally available in my area) and I have noticed that the computerized fuel economy screen no longer matches my regular gas gauge. I know the guy at the gas station said they are having to change out their pumps because they act as if they are empty because they do not recognize the ethynol and wonder if something similar could be happening in my car.

[phantom power]

1. ethanol has 25% less energy per gallon than gasoline.

Your computer gauges are calibrated to gasoline (i assume).

[doni_georgia]

4. My husband said something similar

That ethynol probably has lighter mass than gas. This wouldn't matter if I ever bought a full tank of gas, but I never buy more than $10 at a time, and I don't do that until the screen says "50 miles to empty."

[wtmusic]

2. Is it a Dodge?

Lots of stuff on Google about Dodge gas gauges not working with ethanol.

[doni_georgia]

3. Nope it's a Ford - but my husband's is a Dodge running on same fuel

He never lets his get below a half tank, so he wouldn't notice. I drive only 4 miles a day and usually never buy more than 3 or 4 gallons at a time, since that's all I ever need.

[OKIsItJustMe]

5. Was your car designed to run on ethanol blend?

If not (for example) the float (or the sending unit) in your tank may be degrading.

[poopfuel]

6. email someone who would know

[e-mail]

They can probably help.

[TreasonousBastard]

7. Those computerized fuel economy guages work by...

measuring the intake vacuum pressure, or some such scheme, not by actually measuring fuel used (A good flow meter is expensive, so cars won't have one). They're not all that accurate to begin with, but since E85 has less energy, the equation they used to calculate fuel use from vacuum pressure is even further off.

Go with your regular gas guage and forget the meter-- add ten bucks worth when you're down to a quarter tank. Much less than that and you risk eventually sucking up water and crud from the bottom of the tank. Theoretically, you should keep the tank topped off to avoid condensation, but that's probably overkill in real life.