| Sometimes when you fill up your gas tank, weird | | | | 100% emptied out because if the fuel line was that low |
| numbers can come up. I've seen a Honda Civic, which I | | | | there would be air resistance in the line because it |
| KNOW their gas tanks are only 13 gallons get filled up | | | | would be so close to the bottom of the tank. |
| to 13.1 gallons. How is this possible? | | | | Another part of the gas tank is the "vapor head |
| Tampering with pumps in an unauthorized nature does | | | | space." This is the top most portion of the gas tank |
| happen even though there are very regular checks | | | | compartment. This is almost always left out when a |
| that are done by the state's gas measuring technicians | | | | gas tank is measured for fuel capacity because fuel |
| to ensure their accuracy. There is a very legitimate | | | | can never go that high. It is the part above where the |
| reason that explains this phenomenon though. You | | | | filler pipe leads into the gas tank. |
| might wonder why you've never wondered about this | | | | Now, drivers sometimes fill their tank beyond the |
| or thought about this to yourself because it is very | | | | pumps automatic shut-off point. This results in fuel |
| simple. | | | | either raising up into the filler pipe and over flowing, or |
| Most manufacturers put out estimates that the actual | | | | fuel being drawn into the vapor head space. Also, the |
| capacity of a fuel tank can vary as much as 3 | | | | surface at the gas station could affect this. If you are |
| percent from the rating of the tank capacity because | | | | not on a level surface and the ground is sloped |
| of design characteristics and also because of the | | | | towards the side where the vapor head space is and |
| manufacturing process. Another thing is that the | | | | not where the filler pipe is, you could be filling up the |
| physics that are associated with the components that | | | | vapor head space before the automatic shut off point |
| are built to monitor the emissions system and also the | | | | is reached. You should use extra caution when filling up |
| electronics on the indicators and systems of fuel. | | | | at gas stations that don't have level surfaces because |
| Most manufacturers don't tell which parts of the fuel | | | | if this vapor head space is filled up it could cause a lot |
| tank of the vehicle is that determine the capacity rating | | | | of damage to your car. |
| and this is very important to do. Also, what happens to | | | | Your gas gauge sometimes reads over the Full |
| these components when a vehicle is moving is a | | | | reading and that is because tanks are supposed to be |
| critical component in fuel capacity also. | | | | full much before the tanks actual capacity. Most |
| There is a small area that is located at the bottom of | | | | pumps don't do this though and just fill it up to the top. |
| the fuel tank that is known as the "unusable volume" | | | | Also, when your meter reads E, you should have at |
| This is because it is below the fuel line and can't be | | | | least one or two gallons of gas left. This is called your |
| used by the engine. This exists because it is physically | | | | "gas reserve. |
| impossible to build a gas tank in which it can be totally, | | | | |