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Discussion Starter #1
I put a new tank on the car some time back and I would always wonder why my gas ran out too soon. It's a 25 gallon tank and fuel sending gauge seemed to work fine. Anyway I kept doubting the gauge as I could never put 25 gallons in the tank. Turns out the tank seem to be a lil off in even leveling cause I only can get a about 13 gallons max put in the tank before it runs out from the fillr neck. Further checking and it was lower on the left side than the right, so I tried going up a lil here and there but still cannnot get this thing level. I know it's a 25 gallon tank 100% so is there a special clear angle it should be or just straight up and no tilt at all or what ,it's crazy.
 

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Discussion Starter #3
Yea but how can the fuel pickup stop the total capacity from being put in the tank? I'm going to drop it down tomorrow and see if I can get 25 gallons in there and see
Never heard of that problem. If you can only use HALF of your fuel it's NOT the level of the tank, it's the DEPTH of your fuel pickup.

There is NO WAY that 12 Gallons of fuel is sitting where the sender cannot pick it up.
 

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Yea but how can the fuel pickup stop the total capacity from being put in the tank? I'm going to drop it down tomorrow and see if I can get 25 gallons in there and see
its not what fe said.....
what he's saying is that the pickup tube & sender for some reason must be sitting high in tank so that when your at half tank or less, it's only sucking air & gauge is reading emty....
something is deffently of...
question is what...
i doubt tank is that far out of level......
 

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Ignoring the pickup and sender for a moment - your problem is that you can only fit 13 gallons into the tank from actual empty, right? It's not a fuel gauge issue, or how much you can pick-up, but just how much you can stuff in there? If so, and the tank is not damaged, the fill limit would be reached when both the fill neck and the vent were submerged, or the vent line blocked. Have you checked those items?

David
 

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Even if it clicked off with the vent line blocked and providing back pressure when the fuel level hit the filler neck bottom there would be approximately 23.5 Gallons in the tank....

And with an educated guess, I'm thinking that you are only traveling approximately 120 to 140 miles from full to Empty, am I correct?
 

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Reading that you already replaced the tank, I'm wondering if you (or your installer) oriented the sender correctly? (there are 'tabs' to help the sender's orientation, but ....not sure what your tank has). I agree with the folks here who say that your sender's internal pickup tube is positioned in a way that makes your gauge display empty, when in reality, 1/2 tank or so remains.

As for level; A correct '68 tank will nestle up in there nicely, and the straps are only long enough to reach if iinstalled correctly. There should be some tar paper-like "rubbies" up there, but no bolts or other protrusions interfering with the top of the tank (to my faded memory of doing one decades ago).

I snagged this image off eBay to show the orientation of external supply tube to pickup tube on a '68 sender (or so seller claims) -maybe you can eye-ball this, ie; check that online or in a shop manual's exploded view to see how your sender goes in, then compare to your car and arrive at a definite diagnosis. (float's 'empty' position and pickup tube are correctly shown side-by-side)

good luck on it! Norm

 

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Even if it clicked off with the vent line blocked and providing back pressure when the fuel level hit the filler neck bottom there would be approximately 23.5 Gallons in the tank....
True, but some replacement tanks come with a seal collar and generic 'cut to fit' neck insert, which if not cut, will stick 1/2 way down into the tank. Bingo. Just worth a quick check. Also, running an appropriate impromptu 'dipstick' in would confirm absolute empty and actual fill level. Maybe his local gas station is accidentally pumping 2-for-1 gas and he should just shut up. LOL
:D
David
 

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Discussion Starter #11
Good one 2 for 1 but I get the last laugh, lol I'm paying $1.05 per gallon( the lovely Middle East) for Super. :) but I solved both issues turn out I did not have the tank all the way up to the frame, must been some bad angle/level I had it at. So now 25 gallons going in and fuel sending gauge reading correct now. Thanks for all the suggestion.
LOL I c now. I like 2 4 1 gas!
 

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Discussion Starter #13
Well my forum fellow call it BS all you want, that's what I did took it down and before that I notice it was crooked but even I can't explain that I was missing 12 gallons. Anyway took it down and made sure it was straight ( not an angle) and this time I had a better jack where I really got under there pushed it to the top of frame until it could not move slid it more toward passenger side and also I did not put the fill neck to the furthest point of the tank. No need to BS buddy I'm honest man and its a freakin car we talking about

The fuel tank was WHAT? Not up against the frame meant that you couldn't get all 25 gallons in or out? I call BS on that.

Position of the fuel tank has nothing to do with capacity nor ability of the pickup to remove fuel.
 

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I'm just saying that a 25 gallon tank with dimensions of what yours has, in order to make HALF of the fuel NOT available to the fuel pickup you would "Literally" have the fuel tank Dragging the Ground under the car the off center would be so excessive.

The ONLY way it's not possible for that to happen is if 1/4 of the tank were thrust up behind the rear seat into the rear package tray.

I simply mean the PURE physics of missing 13 gallons are measurably impossible to miss with the naked eye. Your fix as you described it was a simple miscalculation that wasn't perceptible to the naked eye....


Awwwwwwwe schitt, I just think your calculations were WAY off is all. Not callin ya a liar or nothin.
 

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Discussion Starter #15
Yea you have to be right about calculations being off but to the naked eye it was not clear at all, and the 1/4th being in the rear package tray could be it. I mean I took the tank down put it in a tub to verify it was a 25 gallon tank cause I still couldn't believe that it was in that crooked but I guess not installing a tank prior maybe lead to that problem.

Clearly afterwards the tank was much higher in the frame because before I could see it immediately when bending down but now I have to really get low to see the tank.

Thanks for the points cause I am still bugging as to how I wasn't able to put 13 gallons. Funny when I was at the gas station heart was pounding hoping it took a full tank :)


I'm just saying that a 25 gallon tank with dimensions of what yours has, in order to make HALF of the fuel NOT available to the fuel pickup you would "Literally" have the fuel tank Dragging the Ground under the car the off center would be so excessive.

The ONLY way it's not possible for that to happen is if 1/4 of the tank were thrust up behind the rear seat into the rear package tray.

I simply mean the PURE physics of missing 13 gallons are measurably impossible to miss with the naked eye. Your fix as you described it was a simple miscalculation that wasn't perceptible to the naked eye....


Awwwwwwwe schitt, I just think your calculations were WAY off is all. Not callin ya a liar or nothin.
 
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