Fuel Gauge issues
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Fuel Gauge issues
Hey everybody,
Weird issue, been having it for awhile. Filled the tank with 5 gallons and then 8 gallons and the most it will get to is 1/4 tank. Really confused here, so i took out the unit and moved the arm and watched the gauge go all the way to full and back down, so i have it down to a physical problem rather than electrical. I did a bucket test and yes the floater actually floats, but im thinking maybe the unit is not reaching the bottom of the tank or something. Don't know the brand but i know its the general size so im left confused, any ideas?
Thanks, Andrew
Weird issue, been having it for awhile. Filled the tank with 5 gallons and then 8 gallons and the most it will get to is 1/4 tank. Really confused here, so i took out the unit and moved the arm and watched the gauge go all the way to full and back down, so i have it down to a physical problem rather than electrical. I did a bucket test and yes the floater actually floats, but im thinking maybe the unit is not reaching the bottom of the tank or something. Don't know the brand but i know its the general size so im left confused, any ideas?
Thanks, Andrew
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From: Virginia
Are you sure you have the correct sending unit? The rear tank and the side tank are different. Try to guess and hold the sending unit at the angle that it sits mounted in the tank. Then move the float. Would it hit the top of the tank before going full stroke? If it's not too far off you can bend the float arm some.
Lead Driver
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Hey Franklin thanks for the advice, currently have only the front tank, (deleted the back) and yea ill triple check the angle and measurements. Im think maybe its hitting the top of the tank, will keep updated.
Also have a question, looked up the intank units for a 1986 f150 and they all have 2 pin connectors on top whereas mine has 4, does this mean anything?
Thanks, Andrew
Also have a question, looked up the intank units for a 1986 f150 and they all have 2 pin connectors on top whereas mine has 4, does this mean anything?
Thanks, Andrew
FTE Legend
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From: Angier, NC
Hey Franklin thanks for the advice, currently have only the front tank, (deleted the back) and yea ill triple check the angle and measurements. Im think maybe its hitting the top of the tank, will keep updated.
Also have a question, looking at the unit in my tank it is really short and i bet the floater is hitting the top of the tank, could you refer me to a unit the right size? Im pretty sure the front tank is a 16.5 gallon and the truck is efi so it needs 4 pins for the sender and pump.
Thanks, Andrew
Also have a question, looking at the unit in my tank it is really short and i bet the floater is hitting the top of the tank, could you refer me to a unit the right size? Im pretty sure the front tank is a 16.5 gallon and the truck is efi so it needs 4 pins for the sender and pump.
Thanks, Andrew
Oh is it a long bed or short bed truck?
Short bed would be 16 gallons long bed 19 gallons so 2 different sending units at least for my 81 F100 short bed carb motor truck.
Dave ----
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From: Evansville, Indiana
Both 19 gallon tanks on my 1986 EFI have approximately seven gallons each when the needle hits empty. When a tank runs dry, the needle will show about a third of a tank below empty. Always been that way since new.
Assuming you had a couple gallons when you added eight, I would expect the gauge to read about 1/4.
Assuming you had a couple gallons when you added eight, I would expect the gauge to read about 1/4.
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From: Virginia
Both 19 gallon tanks on my 1986 EFI have approximately seven gallons each when the needle hits empty. When a tank runs dry, the needle will show about a third of a tank below empty. Always been that way since new.
Assuming you had a couple gallons when you added eight, I would expect the gauge to read about 1/4.
Assuming you had a couple gallons when you added eight, I would expect the gauge to read about 1/4.
When I was using the front tank before it sprang a leak, I would fill it up and it would stay past "F" for the longest time. Once it move to F, it was on it's way and it did not take very long for it to sweep down the scale to empty. It was fairly accurate though on the empty end of the scale.
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Hey eveybody thanks for responding,
took the bed off because to mess with the unit is impossible without so lol, checked all my lines and connections and really tested the floater and seemed to be working okay. added 5 more gallons, rose right to a quarter again and i check the floater and we werent hitting top. So i threw another 30 bucks and bam it shot up all the way up to full. Reading all of what you said im thinking digger is about spot on. The front tank is a 4 pin 16.5 gallon and apparently it just wasnt reaching the top. Really cant give a specific answer on how but i will update as i use the whole tank.
Thanks everyone, Andrew
took the bed off because to mess with the unit is impossible without so lol, checked all my lines and connections and really tested the floater and seemed to be working okay. added 5 more gallons, rose right to a quarter again and i check the floater and we werent hitting top. So i threw another 30 bucks and bam it shot up all the way up to full. Reading all of what you said im thinking digger is about spot on. The front tank is a 4 pin 16.5 gallon and apparently it just wasnt reaching the top. Really cant give a specific answer on how but i will update as i use the whole tank.
Thanks everyone, Andrew
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Keep in mind that because of the arc the float travels in, when the tank is full the angular movement along the resistor is least per inch of fuel level and as you get closer to empty you get more angular movement at the resistor per inch of fuel level. That makes it look like the top half of the tank lasts longer than the bottom half.
Just don't run out and hit E for Exercise as you usually have to walk from there.
Just don't run out and hit E for Exercise as you usually have to walk from there.
More Turbo
Joined: Oct 2020
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From: Houston
When you pulled the sending unit/float out and tested it in the bucket, how many inches of Vertical travel did it have? That is, how much lower was the float at empty than at full? If the vertical travel is say 6" and the tank depth is 12", there will always be a lag in the indication either at full, empty, or both (keeping in mind the vertical travel will always be something less than the total tank depth).
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From: Angier, NC
That is true, all these trucks have been a little different and you have to learn how the gauge reacts. The 89 I have now, the rear tank is fairly linear in how it reads, but when it gets between empty and 1/4 you had better be looking for a fuel station.
When I was using the front tank before it sprang a leak, I would fill it up and it would stay past "F" for the longest time. Once it move to F, it was on it's way and it did not take very long for it to sweep down the scale to empty. It was fairly accurate though on the empty end of the scale.
When I was using the front tank before it sprang a leak, I would fill it up and it would stay past "F" for the longest time. Once it move to F, it was on it's way and it did not take very long for it to sweep down the scale to empty. It was fairly accurate though on the empty end of the scale.
Mine also set above full and will hang there for a while but once it moves it drops pretty fast
I am happy I added the 19 gallon rear tank as the front 16 gallon just would not cut it.
Dave ----
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