Mileage observation
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Mileage observation
The newest mileage thread has prompted me to post something I've been noticing and ask if I have company: My 2001 XLT 4x4 gets much better mileage if I don't let the tank go below about half full. (In the old days we called this using "the top half of the tank".) It is counter-intuitive, since the truck is more heavily loaded with an extra 15 or so gallons of gasoline, but some other vehicles I've owned have behaved this way. Currently I get 16 mpg in mostly in-town driving if I do this, 12-13 if I don't. And I am averaging multiple fills together to increase the "sample size" in my "poll."
Anyone else experience this type of thing with their Expys?
Anyone else experience this type of thing with their Expys?
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From: All over Texas
You're saying by simply keeping the tank full, you're upwards of 33% better mileage?
I fill my tank up at various levels almost every time I refuel....sometimes near E and other times with half or more still in the tank. I've never experienced the phenomena you mention. Are you relying on the computer or are you physically calculating using actual miles driven divided by # of gallons used?
I fill my tank up at various levels almost every time I refuel....sometimes near E and other times with half or more still in the tank. I've never experienced the phenomena you mention. Are you relying on the computer or are you physically calculating using actual miles driven divided by # of gallons used?
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I'm calculating odometer miles driven divided by gallons used ( = used to fill).
On my past vehicles that got better mileage "on the top of the tank" the difference was not as pronounced. This swing is surprising to me as well. That's why I'm asking if anyone else has a similar experience to report.
On my past vehicles that got better mileage "on the top of the tank" the difference was not as pronounced. This swing is surprising to me as well. That's why I'm asking if anyone else has a similar experience to report.
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That is assuming that when you see your needle at 1/2, you have used exactly 15 gallons(in a 30 gallon tank). Im not sure that is true, because when the needle hits E, your tank is not exactly empty, it still has as much as 3 or 4 gallons in there. i would think the only way to get an exact measurement is to fill your tank all the way, then run it until it runs completely out of gas.
I dont think calculating your milage when your needle is on 1/2 and assuming you just used 15 gallons is accurate.
If you are using some sort of computer to calculate, then dont listen to anything i just said!
I dont think calculating your milage when your needle is on 1/2 and assuming you just used 15 gallons is accurate.
If you are using some sort of computer to calculate, then dont listen to anything i just said!
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oops, i just reread lawtemples reply...
Is it possible that using the "top half of the tank" throw off calcs becuase you can fit more than 30 gals into the truck? If you fill til it overflows, filling the line that leads to the tank, you can get more than 30 gallons into in the truck. I ran it completey dry once and fit 31.4 gallons into the truck.
Is it possible that using the "top half of the tank" throw off calcs becuase you can fit more than 30 gals into the truck? If you fill til it overflows, filling the line that leads to the tank, you can get more than 30 gallons into in the truck. I ran it completey dry once and fit 31.4 gallons into the truck.
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I have also seen variations in "how full" a pump will allow you to fill. One gas station has pumps that will let me fill all the way (and overflow). Another station has more sensitive pumps that will continuously click off when the gas level in the tank gets too high (presumably the pump measures the pressure of gas vapor as it's pumping in order to control the auto shutoff). I agree, the only way to calculate fuel economy accurately and consistently is to fill all the way up every time (until it just starts to overflow). If you fill to the same level each time then the simple miles / gallons calculation will work.
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Logistics Pro
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I fill up at the same pump almost every time (unless I'm traveling) so the shut-off pressure is consistent.
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From: IN
I would think that you might see a higher mpg if you just look at it once or so. If you keep track of it everytime you fuel it will average out. After a few fill ups it won't matter anymore. Does anyone know if these tanks have a "blader"? I have heard that some of the new cars coming out have one and depending on the temp / age / and pressure on the other side will depend on how much fuel you can put in it. This is part of the emisions stuff.
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