So I know that almost everyone has problems with how many gallons they can get in their Jeep. I cannot believe it, but I got just over 19 gallons in it tonight. Even have a picture to prove it. The pump shut off at 16.5 gallons, but I got another 2.5 gallons. It took some patience, but I had the time since the others were not out of the station yet.
2000 Sahara, 3.5" Rubicon Express Lift, 1" spring spacer & 1" Body Lift, 33" or 35" BFG Mud tires, Front & Rear ARB, Rancho 9000 shocks, UCF Ultra High Belly Up
So I know that almost everyone has problems with how many gallons they can get in their Jeep. I cannot believe it, but I got just over 19 gallons in it tonight. Even have a picture to prove it. The pump shut off at 16.5 gallons, but I got another 2.5 gallons. It took some patience, but I had the time since the others were not out of the station yet. Attachment 445970
We have gas stations on almost every block so filling it to the very top is the last think I care about.
Retired my 94 YJ 4cyl 5spd @ 200K
Now in a 04 TJ 4cyl 5spd CV @120K+
Both as a commuter vehicle in NW, NJ
April 2012.downsized and now a 99er.
Dang running on fumes! Filled to the top of the filler neck?
Do Jeeps have a breather tube or anything?
I know the GM trucks were known for damage to the evap by over filling past the auto shut off.
From what I can tell on mine, the breather runs out the evap system: there is not a separate one. There is supposed to be a rollover valve at the top of the tank that the gas would have to pass before leaving the breather/evap so the best you'd get is the valve closing when the gas hits it and the gas comes back at you.
*Disclaimer* I got out of the fuel business in Oklahoma in 1996, so I'm not 100% sure of the calibration of modern pumps.
A gallon of gasoline isn't always a gallon. In fact, it will almost always be off by a percentage. Usually, the pump will dispense slightly less than indicated.
Here in Oklahoma, gas pumps are inspected a couple times a year by the Corporation Commision. They come out with a special 5 gallon fuel can that has a long, slender, open neck. The neck has a graduated viewing window. They pump exactly 5 gallons according to the pump, then check the calibration can. The tolerance is +/- 6 cubic inches per 5 gallons, which is about 1/2%. Anything under that and the pump is shut down until it can be recalibrated and reinspected. If the pump is putting out too much, it's written up and the owner notified, but the pump is not shut down. It's the pump owner who's losing money. This is also rare.
Older pumps start to put out more and more over time. When you have the pump calibrated, you usually want it putting out slightly less than indicated to allow for this gradual increase.
In the OP"s case, he was able to put 19.046 gallons in his tank. If the pump is putting out the minimum allowed, he actually got 18.95 gallons. That's assuming the pump is accurate. If it's not, it could be putting out even less. I've personally seen pumps that did this, due to a mechanical problem with the pump.
There's also the fact that a physical gallon of gas is only accurate at 60 degrees Fahrenheit. When gas is loaded at the refinery or pipeline, the gallons billed are temperature corrected. If the gas is cooler than 60 degrees, more gallons are billed than the physical size of the load. The opposite applies when the gas is warmer. I'd have to check, but some states might allow gas pumps to allow for temperature compensation, where you could be charged for more gallons than physically dispensed. This isn't the case in Oklahoma for gasoline, but it is for some other products, notably LPG.
actually, a gallon IS always a gallon. it is a unit of volume, and that is fixed and unchangeable. The issue is that matter expands and contracts in volume with temperature and atmospheric pressure. What we actually want to get from the gasoline (or other fuel) is what matters, and that is energy. The one type of measurement that we can use that will remain constant is weight. The amount of energy measured in BTUs remains the same, regardless of volume. All engines consume fuel by weight; but for some strange reason, we measure it by volume.
Its not a big deal for most of us, because the difference in btu's you're getting for your dollar on a hot day vs a cold day is so small, it isn't worth fussing over. But for large commercial/military aircraft, which operate in a much broader temp/pressure ranges, and consume such large amounts, it does make a big difference. And that is why they always reference fuel in "pounds" (or kilos).