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ran out of gas, but still have gas!!!

960 views 11 replies 6 participants last post by  bamasteeler 
#1 ·
twice now in the last month i have been driving my jeep down the highway when all of sudden it starts sputtering and rpm's decrease until engine just dies. one occassion i was able to limp into gas station but this last time i wasnt. the problem i am having is when i do fill the tank back up i am only putting approx. 12 gallons back into my 15 gallon tank.

so my question is why cant i use the last 3 gallons? i understand all tanks have a bit of unusable fuel but 3 gallons seems a bit high to me. the tank was replaced sometime with another owner and now is a 15 gallon poly (plastic) tank.

i have had it out before and inside of tank was clean, new sending unit was installed last winter. i measured from sending unit plate to bottom of pickup tube and was roughly 10 inches. then measured from top of tank to bottom of inside of tank and got roughly 10 inches. so in my messed up brain of math i would assume my pickup is sitting on bottom of tank. if that was the case once again in my screwed up head i should be able to use majority of my gas.

there were times at the beginning of the year that i would refuel and put close to 14 gallons in tank, so why can i not get that much back out now?

i did replace my mechanical fuel pump about 2 months ago when it went out.
is it possible that this new pump isnt strong enough to suck up the last 3 gallons??

thanks for any input.
 
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#2 ·
After I did my SBC swap I ran out of gas. I don't have a working gauge and the new motor is a lot more thirsty than I anticipated getting only 7 MPG. I had a tow truck tow me to a gas station and I was only able to get 18 gallons into my 20 gallon tank including the extra gas in the filler tube. I guess the fuel pickup in our tanks aren't designed to use the fuel at the bottom of the tank.

I might add that I'm using a new fuel pump on my 383.
 
#4 ·
hp_lovecraft said:
I was never able to use the last 3 gallons until I installed the "screen" at the end. Now its good up until the last 1/2 gallon or so. Does your sender unit have the screen?
Yes it does/did when I installed it, guess it's time to drop the tank again and need to check that, good idea thanks
 
#5 ·
Also check that the skid isn't dinged upwards. Easy enough to bend it right under the pickup.
 
#8 ·
i find i have about 5 gallons or so at empty but with the 91-95 efi i just put on its fuel cut at a 1/4 tank cause of no baffles

do you have a pin hole on your feed maybe its sucking air?

i would drop the tank and chack the length on your sending unit to the depth of the tank aftermark parts are just that you may need to cut the down tube and scab on an inch or so. the pick up shouldn't be on the bottom all the way but pretty close. maybe someone has a stock set up to go off of. i would measure mine for u but i did the sender a few years back and it seams off
 
#9 ·
nicknoty said:
i find i have about 5 gallons or so at empty but with the 91-95 efi i just put on its fuel cut at a 1/4 tank cause of no baffles

do you have a pin hole on your feed maybe its sucking air?

i would drop the tank and chack the length on your sending unit to the depth of the tank aftermark parts are just that you may need to cut the down tube and scab on an inch or so. the pick up shouldn't be on the bottom all the way but pretty close. maybe someone has a stock set up to go off of. i would measure mine for u but i did the sender a few years back and it seams off
Pin hole? 30 year old vehicle only owned it for about a year so anything is possible..

Measures roughly 10 inches to bottom of tank as did the sending unit
 
#10 ·
i only ask about the pin hole cause i was getting fuel cut around 2500rpm and i thought all kinds of things and got tired of playing with the weber and just jumped to the efi swap and when i droped the tank to upgrade to high psi line i had a small rip in the send line which was only 3 yrs old, also the metal line can and does rust out or in however you wanna look at it
 
#11 ·
nicknoty said:
i only ask about the pin hole cause i was getting fuel cut around 2500rpm and i thought all kinds of things and got tired of playing with the weber and just jumped to the efi swap and when i droped the tank to upgrade to high psi line i had a small rip in the send line which was only 3 yrs old, also the metal line can and does rust out or in however you wanna look at it
Yes understood what you meant and it will def be one of the many things I will look at when I drop the tank, prob will replace the rubber lines and blow out the hard lines at minimum
 
#12 ·
Dropped tank today and found the pick up sock had fallen off the tube. Wich essentially was leaving 2 inches of gas at bottoms of my tank that I couldn't pick up an use!!

Put a little bead of soder on the pick up tube then side pick up sock back on, makes it alot tighter, don't think it should fall off again :)
 
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