filling gas and tank pressure

[ebox86]

Hi guys, have another problem with my car since putting it all back together. One of the many issues im trying to work out in an attempt to get it toward daily-driver-hood.

When getting gas this morning, I filler her up and heard the nozzle handle click, so I pulled the handle out and gas gushed out of the tank inlet. Note, the handle was not depressed when i pulled it out, but the gas that came out was apparently from it building up along the neck of the fill line to the tank. It filled it too much and didn't stop the nozzle due to the presssure of the tank.

What could cause this? I have not visually inspected the fuel pump/sender, but I will do that tonight.

Has anyone else experienced this?

thanks

[jlevie]

That would sound like a blockage in the vent system.

[ebox86]

That would sound like a blockage in the vent system.

Where is the vent system? Is it one of the hoses on top of the fuel pump/sender unit?

[Cephas]

The vent sysytem is in the right rear wheel well. Take the plastic guards out and you will find a series of hoses and a catch can. There is a shield that looks like it covers the positive battery wire, but it doesn't. That's the cover for one of the main vent lines.

[jeffnhiscars]

Keep in mind that the back pressure required to shut off a gas nozzle is adjustable and they tnd to all be a little different. I've had some that did not turn off at all and gas would overflow...which is why many stations no longer have the ratchet locks, why you don't walk away while it's pumping and maybe...just maybe...a good reason not to smoke while filling :)

[Codym42]

Hmm... I have the opposite problem. At certain gas stations it shuts off after pumping like 2 gallons with an almost empty tank. I have to position the nozzle a different way for gas to pump. At other stations everything works fine. Is my vent system messed up too?

[jeffnhiscars]

Hmm... I have the opposite problem. At certain gas stations it shuts off after pumping like 2 gallons with an almost empty tank. I have to position the nozzle a different way for gas to pump. At other stations everything works fine. Is my vent system messed up too?

It's possible that a 20+ yo car can have vent restrictions but what you describe sounds more like another maladjusted pump. If it's your favorite station then tell them. They are all on maintenance contracts anyway.

[Codym42]

It's possible that a 20+ yo car can have vent restrictions but what you describe sounds more like another maladjusted pump. If it's your favorite station then tell them. They are all on maintenance contracts anyway.

I think you're right about the pump. I took my new e30 out today and filled up and the same thing happened. Never happens at the Quiktrip near me but anywhere else is hit or miss. If I turn the handle 45 degrees it's fine.

[ebox86]

Well it happened to me again today, I went to fill up and at about 3/4 tank has stars leaking from the fill spout and along the line that goes to the tank. Other than the vents, is there anything else that would cause this? Very frustrating when has leaks all over the place everytime I go to fill up...

[jeffnhiscars]

Well it happened to me again today, I went to fill up and at about 3/4 tank has stars leaking from the fill spout and along the line that goes to the tank. Other than the vents, is there anything else that would cause this? Very frustrating when has leaks all over the place everytime I go to fill up...

There are 2 rubber connections to the metal fill pipe. One is the large hose that connects it to the tank and that one would leak at about 1/4 tank and wouldn't stop til the level went below that. The other is the vent connector in the wheel well which has already been mentioned.

You need to pull the wheel and liner and replace the hoses

[george graves]

Safety George Say.....: Don't park in an attached garage if you think your car might have fuel system issues. The more you know...

[ebox86]

There are 2 rubber connections to the metal fill pipe. One is the large hose that connects it to the tank and that one would leak at about 1/4 tank and wouldn't stop til the level went below that. The other is the vent connector in the wheel well which has already been mentioned.

You need to pull the wheel and liner and replace the hoses

Thanks jeff, i will do this and replace the hoses, it makes sense too, those hoses are probably so old.

Safety George Say.....: Don't park in an attached garage if you think your car might have fuel system issues. The more you know...

George thanks, thats a good idea lol, i hate having these issues.

Oh and btw, don't link to youtube for simple animation like that, what is this 2006?

[ebox86]

There are 2 rubber connections to the metal fill pipe. One is the large hose that connects it to the tank and that one would leak at about 1/4 tank and wouldn't stop til the level went below that. The other is the vent connector in the wheel well which has already been mentioned.

You need to pull the wheel and liner and replace the hoses

Do you happen to know which part number or which number on this realoem diagram that hose is?

http://realoem.com/bmw/showparts.do?model=1113&mospid=47309&btnr=16_0107&hg=16&fg=10

[jeffnhiscars]

The vent hose #5 is your primary suspect but any of those could be disconnected or damaged if you go to the fuel tank diagram #17 is your main fill hose which is tough to change with the subframe in place. If you do go in there do the grommet #15.as well

http://realoem.com/bmw/showparts.do?model=1113&mospid=47309&btnr=16_0046&hg=16&fg=05

[ebox86]

Thanks, i took both panels off, the one that covers the overflow tank and the one that covers the lines behind the strut and other than the massive amount of dirt and soot and buildup that was removed and cleaned, i massages and flexed the #5 hose and it indeed looks to be shot.

However, after massaging that hose for a bit and then filling up, i didn't have any spillage this time, so I think it may have just been too tight and wasn't allowing that much gas through. Either way, it needs replaced but is working for now.

Thanks for the help!