So one night i was at the local Chevron station filling up on a tank of 91. I notice right behind me at another pump there's this beat up mazda 1 ton pickup. The guy was sitting in there but not getting out. Took me a while to fill up, and the whole time the truck was sitting there.

After i'm done, i get back in my car and start to drive off. As soon as i drive away, i look in my rearview and he moves up to the pump where i was at and starts to fill. Keep in mind there were other pumps open. I assume he's the kind of guy that thinks, "He's filling up on 91... maybe i'll get a bit of 91 even though i buy 87. *snicker, snicker*" BTW: it was one of those pumps that only have one nozzel, but 3 different grades to choose from.

Whatever. I know enough that if you mix octanes, it'll eventually be a mute point as the more 87 you put in, the more useless the 91 becomes.

I guess my question is, how do gas pumps actually work? Is there a small amount of gas left in the hose after you stop the trigger?

I've also seen some people pull up the hose to "let gravity" pull the rest of the gas down into the tank. Does that really work?

 

I'm goning to yes, but it's such a small amount in comparison to lets say just a gallon, it's a drop in the bucket and you gain nothing really.

 

The valve is in the handle. So no, pulling up on the hose wont empty it into your tank. You might get a fed extra drops by turning the nozzle upside-down, but I think the momentum of the gas coming out will nearly empty all of it anyways.

 

i love when I see people doing whatever they can to try to get an extra drop

 

OK, stupid question. What makes the pump stop pumping the gas. I have always assumed that there was a sensor on the nozel, but when I look at some old beat up nozel that still stops when I'm full I begin to wonder...

 

Read this: http://auto.howstuffworks.com/question25.htm

 

^^^ Cool...
Always wondered what that little hole was for.

 

i have always wondered this...how do you know if you are getting mid grade or premium. If you ever go to a shell station on the pump it tells you how many gallons have been pumped out of the tank since the pump has been in use. There is a guage for the 87 octane, but only 1 guage for the 89 and 93 octane. So the 89 and 93 share the same guage. Are you really getting 93 octane or are you paying for 93 octane and really getting 89 octane????

 

The state checks pumps regularly, so any funny business should be caught then.

 

hahah i agree

 

Its "moot" not mute, im not hating, its just so you know

 

^^^ Ooops... slight oversight on my part =P

I'll call you "Grammarcommando" j/k

 

There usually isn't a "mid grade" tank in the ground. 89 is created by mixing the 87 and 93 in the pump. I think you should see both phisical counters moving if you're pumping 89.

Oh, and are you paying too much for 89 if you buy it? Well, in your case 89 is made by mixing 2/3 part 87 with 1/3 part 93 as you pump. I bet you pay too much if you buy the 89 (as opposed to just mixing it yourself).

 

We have our own gas and diesel tanks that we use for our farm machinery. The "pumps" are powered by gravity. When we're done fueling, we hold the hose up to get the last drops. It's not usually that much gas (maybe a quarter of a can of Coke) but since we've already paid for it, we might as well use it rather than let it evaporate or drip out.

 

I see this from a different perspective....when I fill my motorcycle, I milk the previous gas out on the ground so the drops do not remove the wax on my tank.