My Fuel Tank Won't Fill Completely

[kevinbakon]

The last few times I have filled up on gas, I noticed that my tank won't fill completely.

I have the message center on my 2008, V8 STA and I generally wait until the approximate remaining milage reads 10 to 25 miles.

It only fills to between 17 and 19 gallons and sure enough my gauge doesn't rise to the very top.

My first thought was that it might be the shut off valve at the pump, but I have filled up at varying gas stations.

I have owned the truck for a year now and it has only recently started happening and it happens every time now.

While searching the web, I have read that the outside temperature may cause this premature shut off, but within the last few times, the temp has varied between 55 and 90 degrees.

My findings on the web also have indicated that the flow of the gas can cause bubbles which give a false "full tank" signal.

The last time I filled up, I ended up manually "pumping" the handle until the gas was visible, no bubbles, once again 18 gallons and the needle didn't rise completely.

Before I take it to the dealer I thought I'd ask if anyone on this site has had the same occurrence or knows of any suggestions so I don't go into the dealership completely uneducated and unprepared.

Thanks for any suggestions or advice.

 

[Ben Schepper]

I read something similiar to this was happening on newer gt mustangs. On the mustangs it had to do with the way the filler hose was routed.

 

[kevinbakon]

Thanks Ben.

I'll read up on the mustangs . . . although I don't imagine the way the ST is routed is exactly like the mustang, you may be on to something.

The weird thing is that I've probably filled up a total of 70 times in the last year, it has only recently started happening and its now consistent.

 

[Todd Z]

Are you holding the nozzle in a different position... That can make a difference too.. Too far up or down.... Maybe out a little so you don't scratch the paint ??



Todd Z

 

[Scott Doughtie]

LOL...just filled up yesterday after being down to 14 miles to empty. I put a shade under 21 gallons in at Costco. I shake the truck a little to try and get the air bubbles out of the tank. I wondered the same thing about the capacity. I made it down to 1 mile to emtpty one time and it still only took 21 gals to fill it up.



I wonder and I don't know if this has been investigated...does the Gen II ST have an internal fuel pump that is inside of the fuel tank ala the Gen II Taurus? My ex-wife's 98' SHO had the fuel pump inside the fuel tank, which allowed for an extra gallon and a half past empty.

 

[scott degroot]

Sounds like the evap canister vent filter may be plugged or possiby the vent solenoid is partially plugged. When either one of these gets plugged or malfunctions they will not let the fuel vapors vent properly when refueling and therefore cause the tank to not refuel all the way or in other cases keep kicking the fuel pump off(which must be what is happening to you becuase you think it is full when it isn't). The only other possibility is that the tank is full and the fuel level sending unit located inside of the tank is bad adn not reading accurately.

 

[kevinbakon]

Are you holding the nozzle in a different position... That can make a difference too.. Too far up or down....

That's one of the first things I trouble shot . . . . I've pulled it out (almost completely), pushed it in (as much as possible) and everywhere in between. I've lifted it up/forward, pushed it down/back, twisted it to the right and to the left. As well, I've tried every combination of all these positions.

I shake the truck a little to try and get the air bubbles out of the tank

I haven't tried that yet. I'll give it a try. It may be worth a shot, but I doubt it will permanently fix the occurrence.



l1tech, thanks for the technical jargon . . . This is all Greek to me, but I get the general concepts that you are mentioning and I greatly appreciate it. If "shaking" or "rocking" the truck at fill up doesn't help, then I'll end up taking it to Ford.

 

[Steven D]

when you fill it to the capacity that it lets you and your guage needle doesn't go all the way up, how many miles does your computer tell you that you have until empty? Is it the same as when your guage used to read full or is it a gallon or two less?



For instance, if you normally fill it up to 22 gallons and your miles to empty reads say 400 miles to empty and now you are filling it up, is the new reading 350 or so or is it still 400? May be a problem with your dash gas guage, you may be full, but the needle may be skewed.

 

[kevinbakon]

Its reading right around 300 . . . no where near where it used to be @ 350

 

[EddieS'04]

sometimes on my '04. If I let it get down to 1/4 tank. It is as if there are alot of vapor. Keeps clicking off on me. I rotate the nozzle 90 degrees and start slow. Then Im able to kick it to full throttle fillup.