Gas tank won’t fully fill

[JExpedition07]

The last few times I’ve stopped to get gas the expy is only taking roughly $68 worth in fuel and it clicks off, even if I add a few more clicks the fuel gauge is below full and reads less miles to E than normally. It’s a Minor annoyance. Does not click off mid fill just toward end but I can’t pack it full like normally. Any ideas on why it won’t take that last two or three gallons it used to? Never normally add after that initial click but with it not taking enough gas I’ve been adding after anyway.

I don’t believe it’s a float problem, as the pump reflects the same results of less fuel than normal.

Not a huge deal just has my curiosity peaked. Could just be a fluke.

 

[JExpedition07]

This is after filling up:


Normally 425 miles to E.

 

[Munkiebunz3]

Do you use the same pump?
Do you keep track of the # of gallons you usually pump?
Track mpg per fillup?
Track actual miles traveled vs the estimate?
The shutoff is controlled by the pump when it senses the splash-back. If it happens at every pump at every fillup then you have a problem with your fill port or a bad fuel level sensor.
I live in Los Angeles and my fuel prices are different I don't know what $68 of gas means. Anyone else who doesn't live where you do will also not understand.

 

[JExpedition07]

Do you use the same pump?
Do you keep track of the # of gallons you usually pump?
Track mpg per fillup?
Track actual miles traveled vs the estimate?
The shutoff is controlled by the pump when it senses the splash-back. If it happens at every pump at every fillup then you have a problem with your fill port or a bad fuel level sensor.
I live in Los Angeles and my fuel prices are different I don't know what $68 of gas means. Anyone else who doesn't live where you do will also not understand.

I don’t and after thinking about it you are probably correct on fuel level sensor. The vehicle likely has more gas than it thinks when it comes down on E fooling me into thinking it’s actually empty. I’ll see if it corrects itself..... not sure if it’s something I should live with or not...

 

[Dennis_H]

My 2010 had the same issue. It was the sending unit. It shut off at full, but reported 3/4 tank. It happened soon after I added a bottle of Heet to it, but I don't think it had anything to do with it. Just seemed to be a coincidence, but I haven't added anything since.

 

[JExpedition07]

My 2010 had the same issue. It was the sending unit. It shut off at full, but reported 3/4 tank. It happened soon after I added a bottle of Heet to it, but I don't think it had anything to do with it. Just seemed to be a coincidence, but I haven't added anything since.

Did you replace the sending unit? I don’t know that it’s worth it to drop the tank for it reading 3 gallons off. Plus if anything it’s giving me even more reserve capacity if reading low.

 

[Munkiebunz3]

Typically the sending unit will be off in a certain range of fuel tank level rather than being off throughout the range of the tank level because it's a simple potentiometer. If the resistance value at the top is a little off it will register being in the first 1/4 tank for much longer than the lowest 1/4 tank. This is why I always get a baseline mpg, know my tank capacity & guesstimate how many gallons I have left. Then I cross reference that with the # of gallons filled at the station. I've seen too many tank sending units fail on other cars to trust my car telling me how much fuel is left.
Do you trust your woman saying "everything is fine" when you know you did something bad & you know she knows?

 

[Plati]

My 2003 level sensor has gotten stuck over the years. Mechanic told me if might be sulphur buildup boogering up mechanism. I just waited it out and it would start working again. I used to watch miles since fillup to make sure I never ran dry.

 

[JExpedition07]

Last fill it took 22 gallons if I remember correctly, I filled it back up again this time right on E and it took about 22 gallons again. 28 gallon tank.

 

[Munkiebunz3]

Last fill it took 22 gallons if I remember correctly, I filled it back up again this time right on E and it took about 22 gallons again. 28 gallon tank.

This sounds like it's the total resistance rather than a spot in the level. I wonder if it's easy to check your power & ground. Might be easier to have a 5 gal Jerry can & see how long it stays on E and how many gallons it takes after you fill with the 5gal Jerry can. Might actually have the "extra" reserve like you mentioned earlier.

 

[Plati]

I was thinkin the jerrycan idea also, but it IS a risk to drive around with gas in the cabin. Small risk but nonetheless.

I also thought if it was me .... I'd keep gushing gas in until it was obviously full. BAD IDEA. After looking at the fill tube recently and finding out about the EVAP system (which I never knew was there) that sounds like another risky game to play.

 

[JExpedition07]

I’m at 3/4 tank now I’m stopping again to top it off (first click) and I’ll see where it lands.

 

[JExpedition07]

This where it landed:

 

[Don Hall]

Common Ford problem. Research fuel vapor canister - about $160 from RockAuto, about 1 hour labor, if
you can't do it yourself.

 

[Msport]

I saw somewhere in youtube talking about the evap system and explaining symptoms of a bad Vapor Canister Vent Valve/Solenoid. One of the problems with the vent valve not working properly was not being able to fill up the tank to full, but the first indication would be the engine service light coming ON (p0455 the common code for bad gas cap).

 

[Don Hall]

My 2004 XP, no fill problem since new. Wife's 2006 Mustang is on the 3rd canister. Never a code, would only take half-a-tank of fuel.

Original canister lasted 12 years, second canister lasted 3 years.
Replacing the canister always solved the problem immediately.

 

[JExpedition07]

Well seems something corrected itself, the gas gauge sat at at the same spot for some miles of driving. Then dropped below, and now it fills to 425 Miles to E again. Huh, I’m stumped. But also not worried about it.

 

[TDBDLB]

Like MrSticker noted, could be sulphur buildup on tank solenoid reader. Had this happen on Vette when moved to KC where sulphuric content was higher in gas. Techron fuel cleaner fixed in just a few days evertime fuel gauge acted up.

 

[JExpedition07]

Just an update, the last few fill ups it didn’t read full yet again. I then bought 2 bottles of Techtron concentrate fuel system cleaner and ran it through a tank full. Just filled it up and it reads proper and full again! Thanks for the suggestion on Techtron!

 

[Eagle 71]

I had a ’98 Explorer and an ’01 Mountaineer that both displayed the exact same symptoms. They both hit ‘full’, when I could (slowly, manually, a quarter of a gallon at a time, pump shuts off, repeat) still add another five gallons to the tank. Had to keep an eye on the end of the filler tube when doing this though, to ensure I didn’t ‘overfill’ and have an overspill issue. That process ultimately worked…needed some patience towards the end of the 5-gal top-off though.

Would’a been nice if, back in the day, similar bubbas on the Exploder Forum had found out about the magic of Techtron and posted the results.