Gas pump miscalibrated?

[trebuchet03]

The questions becomes: is the SG a better estimate of FE or fill-up???

Fill-up On an individual tank - it might not be accurate... But, for running averages...

[Gary Palmer]

I don't think the gas pump is miscalibrated.

When I replaced the fuel pump on my 89 Civic Wagon, I had it totally empty. I put 2 gallons of gas in, to get it running. Then I went to the gas station and put in an additional 9.8 gallons. The tank is only supposed to be a 10 gallon tank, but I think that is really for the sake of the gas gauge and the fact that you have to have some fuel sloshing in the tank, for the pump to be able to even pick up.

If you wanted to haul a couple of gallons of gas, in the car, you could run it out and then see how much the tank will hold. I'd guess that it will hold 11, maybe 11.5, if it's really low.

[GasSavers_Ryland]

gas pumps are not alwas accurite, any idea how much gas you had left in your tank? I've put over 10 gallons in my 10 gallon gas tank befor, but it was pretty close to empty, so it seems possible, but we've also put "14" gallons in an 11 gallon tank, and the gas gauge said it was only 3/4 full, and at that point, with a little arguing with the gas station they only charged for half.

[itjstagame]

Also, 'supposedly', I've heard to fill up in the early morning or late night because that gas is more dense. That is 'supposedly', 10 gallons of cold gas (at night) when warmed up (during the day) will actually be more than 10 gallons.

I'm not sure how significant this is, being a liquid and probably only the difference from at most 40-50F and 100F I can't see how the gas can really change in density that much, but I've seen that suggestion on more than one site... so not sure.

Anyway, my point is, if it was 100F out and 1pm, then maybe you pump 10.1 gallon of gas, but maybe it was only 9.9gal cold?

[1993CivicVX]

Originally Posted by Ryland

gas pumps are not alwas accurite, any idea how much gas you had left in your tank? I've put over 10 gallons in my 10 gallon gas tank befor, but it was pretty close to empty, so it seems possible, but we've also put "14" gallons in an 11 gallon tank, and the gas gauge said it was only 3/4 full, and at that point, with a little arguing with the gas station they only charged for half.

holy ****, that's crazy. They're charging only half is admission of guilt. I checked the gas station and it wasn't miscalibrated.

[trebuchet03]

Originally Posted by itjstagame

Also, 'supposedly', I've heard to fill up in the early morning or late night because that gas is more dense. That is 'supposedly', 10 gallons of cold gas (at night) when warmed up (during the day) will actually be more than 10 gallons.

I'm not sure how significant this is, being a liquid and probably only the difference from at most 40-50F and 100F I can't see how the gas can really change in density that much, but I've seen that suggestion on more than one site... so not sure.

Anyway, my point is, if it was 100F out and 1pm, then maybe you pump 10.1 gallon of gas, but maybe it was only 9.9gal cold?

That's air temperature The fuel is stored in very large tanks (think 10K gallons) underground where temperature is much more stable. Daily temperature swings won't raise the tank temperature significantly. There's a thread somewhere on here with some calculations - I think it was something like 9 or 10 gallons over a 50 degree difference for the entire 10,000 gallon storage tanks