Science Project

Agengr was having trouble with his truck running. The trouble was fuel supply. The question was fuel tank or fuel pump. He got a fuel pump from Gunny. I got the tank to take to a local machine shop to clean it out and fix the drain plug. Once that was done, he wanted me to determine if the pick up tube was solid all the way down.

Colton and I figured out a way to test it today. We hooked my brake bleeder vacuum pump to where the fuel line would hook to the p/u tube. I have the little cup that catches brake fluid in line so it would catch any liquid picked up. I didn't want to put gas in there in case we had to do some cutting/welding to make the p/u tube work. So, since the drain plug now works, we decided on water. I have a 32 ounce paint mixing cup that is marked like a measuring cup. I didn't want to spill a bunch between the sink and the tank, so we did 26 ounces per cup.

26, 52, 78 and 104 ounces all produced nothing. I could actually hear the vacuum in the tank while Colton pumped away. 130 ounces was the winner. The water sucked up right away. 128 is a gallon and I probably spilt a little on each cup. So, on his tank at least a minimum of 1 gallon is needed to get fuel out of the tank. Now, I really don't want to look up the formulas, but 1 gallon isn't all that much considering the square inches of the bottom of the tank.

Just wanted to share with everybody since fuel supply comes up a lot. A minumum of 1 gallon is needed in the tank to make it run. Plus, if you are out of gas in a blizard, you know now that you can drain about a gallon out of the tank to light a fire to keep you warm. Hope this helps you.

Very intersting Tim. Thanks for the info.

Thank you Tim. At least that is one less problem I dont have to worry about.

From my quick research, one gallon = 231 cubic inches. Since I am 100 miles from my truck right now, much less my gas tank, I am going to estimate the base of the tank as 20 in. by 30 in. That means the pick up tube should be about 0.385 inches from the base.

Tim, great analysis. Except for the blizzard bit. It rarely snows in south texas much less a blizzard.

Good tech AND a teaching opportunity as well!:)

My trucks fuel tank also had about a gallon left in it when I ran out of gas. Good info to know.