Fuel miles percentage

[AmsterDutch]

My fuel miles percentage on my Instrument Cluster is dropping way to fast...anyone have this issue the actual fuel gauge needle seems to be dropping normal but the miles percentage gauge/ indicator is falling down way to fast ...Example...
I put $20 dollars of gas in my car and upon getting in my 2002 Lincoln LSE V8 the miles percentage said 120 miles until empty... I drive 2 blocks and it says 116 ...how can it drop 4 miles in 2 blocks I drive a mile home and it's at 110? Any ideas or remedies are appreciated

 

[AmsterDutch]

Just want to use the correct definition so let me explain it like this...While driving my '02 LSE V8 with the computer display showing approximately 120 miles to empty, the computer display said 116 after only driving 2 blocks... Knowing that it had said 120 miles to empty only a block or two before, I continued home which is about a mile maybe less home ...then my computer display said 110 miles to empty

 

[joegr]

That's not any percentage. (Sorry, but that was really throwing me off.) That's the estimated range you are talking about. Estimated range is based on the amount of gasoline you have (fuel gauge), and your recent MPG. If you recently reset your MPG reading or recently had the battery disconnected, then it will only have a few miles to base that guess on, and so will have noticeable adjustments as it goes. If as you keep driving, it finds that it was too pessimistic, then it will slow down the rate that it ticks the miles down (you might travel two miles, but the estimated range might decrease by only one mile). On the other hand, if it seems like you are getting much worse mileage than its previous estimate, it may decrease the range by two or three miles when you have only traveled one mile.

It measures your current MPG by the distance traveled (wheel speed sensors) and the amount of fuel used (calculated by the amount of time the injectors are held open at the current measured fuel pressure).

 

[AmsterDutch]

That's not any percentage. (Sorry, but that was really throwing me off.) That's the estimated range you are talking about. Estimated range is based on the amount of gasoline you have (fuel gauge), and your recent MPG. If you recently reset your MPG reading or recently had the battery disconnected, then it will only have a few miles to base that guess on, and so will have noticeable adjustments as it goes. If as you keep driving, it finds that it was too pessimistic, then it will slow down the rate that it ticks the miles down (you might travel two miles, but the estimated range might decrease by only one mile). On the other hand, if it seems like you are getting much worse mileage than its previous estimate, it may decrease the range by two or three miles when you have only traveled one mile.

It measures your current MPG by the distance traveled (wheel speed sensors) and the amount of fuel used (calculated by the amount of time the injectors are held open at the current measured fuel pressure).

Holy Smoke...Once again I learned something new about this old Relic ...thanks so much Joe! That is the best news I could get...didn't want to battle another fuel pump replacement

 

[milehighmikey]

Also idle time without driving eats distance to empty miles. As well as hammering the throttle does. Also figure in that they are adding or trying to add more ethanol to the fuel mix to extend the barrels of oil needed to produce the fuel for our tanks in some areas. The more ethanol in the mix, the worse your efficiency will be. The upside is that you might feel as though your car is running stronger, depending on how much ethanol is in the fuel.

 

[AmsterDutch]

Also idle time without driving eats distance to empty miles. As well as hammering the throttle does. Also figure in that they are adding or trying to add more ethanol to the fuel mix to extend the barrels of oil needed to produce the fuel for our tanks in some areas. The more ethanol in the mix, the worse your efficiency will be. The upside is that you might feel as though your car is running stronger, depending on how much ethanol is in the fuel.

Makes sense ...

 

[clubairth]

Ethanol is NOT less efficient! Ethanol contains less energy per gallon. So using the same amount of energy requires more gallons of Ethanol.

If the LS was a DI car like my wife's Eco-Boost MKS you will find Ethanol is a superior fuel to gasoline. Runs cooler so the engines can have much higher compression ratios which lead to massively increased efficiency. Since that car is turbo charged the big increase in octane that Ethanol provides allows much higher boost pressures for large increases in power.

Anther huge benefit is that Ethanol burns so clean it removes carbon from the combustion chamber. If you run meth injection in a regular fuel injected car you will also see the cleaning effect.

We now have 3.5L Eco-Boost SHO's running over 1000HP! Yes that's no typo either. Most are running E30 or something similar. It's crazy how well it works because those cars have flex-fuel sensors and can handle almost any mixture of Alcohol/gasoline on the fly! The engine and tunes adjust itself as the fuel changes composition!
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[04_Sport_LS]

Holy Smoke...Once again I learned something new about this old Relic ...thanks so much Joe! That is the best news I could get...didn't want to battle another fuel pump replacement

Today. Rural state route. 20 mile trip to next town. Temp 90 degrees. No wind. Flat ground. Speed... 57-58 mph (no cruise control).

Just shows what the LS is capable of... even at 257k miles.

 

[04_Sport_LS]

Ethanol is NOT less efficient! Ethanol contains less energy per gallon. So using the same amount of energy requires more gallons of Ethanol.

Which equates to less MPG... which means less efficient (at least for most cars).

There was a gas station in my area that sold non-ethanol 91 octane fuel up until 3 years ago.

I got my best milage ever... from the non ethanol 91 fuel... and the LS had more power using it.

 

[clubairth]

Yes but it's not less efficient. Maybe this chart will help explain? Different fuels contain different amount of energy per gallon. Your only looking at MPG and not fuel efficiency. Think about why Diesel gives better fuel mileage? It's because Diesel contains more energy per gallon.

From the above chart;
Diesel has 128,000-138,000 BTU/Gal
Gasoline has 112,000-120,000 BTU/Gal
Ethanol only has 76,330-84,530 BTU/Gal
Methanol only has 57,250-65,200 BTU/Gal

As you can see this is exactly what happens in real life. Diesel gives the highest MPG BECAUSE it has the highest energy per GALLON. Then gasoline and then Ethanol and finally Methanol.
It's all about the energy density of the fuel.
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[04_Sport_LS]

And/but diesel "self combusts" under high pressure/high compression ratio.

All (most) other fuels require an external source of ignition, (spark plugs).