Fuel backing up out of filler neck.

[Troopy]

Hi all, have just had a full new fuel system put on the van due to the fuel tank being under the bed in the back when I got it for some reason.

Went to fill it for the first time and as soon as I pulled the trigger on the pump it started backing up and going everywhere!!

Didn't seem to matter how gentle I was with the trigger, the result always seemed to be the same.

Is there a knack to filling up these old'uns that I am missing or is there some adjustment that I can do to stop it.

Think I ended up with more on the forecourt floor than in the tank

[Oldiebut goodie]

Presumably the vent lines are incorrect/trapped somewhere. I would take the vent off the filler pipe and see if you can blow down it, air line if not brave enough to use your lungs.

[adie89]

Your description is... concerning. I’ve never heard of a vehicle having the fuel tank inside. However, you do get water tanks under the bench. If the cap is not marked it could be mistaken for a fuel cap quite easily.
The largest vent is the filler neck. Vent pipes would be suspected if you had fuel starvation issues as air not entering the tank as the fuel is used causes a vacuum.

[Oldiebut goodie]

If the vent pipe to the filler neck is blocked it will cause blow back. Try it. Clamp yours before you fill up next time.

[adie89]

I hate to argue but an 8mm bore pipe that has a one way valve to prevent leakage during rollover, will not cause blowback compared to the 50mm or so hole of the top of the tank. So I’m afraid you have been misinformed at some point, I teach this as described by manufacturers and text books.

[Oldiebut goodie]

I teach it as seen and experienced! Not only on my VW but also on my Merc both have had a blocked vent at one point. I have not misinformed myself as in both cases remedying the vent operation restored full fuel fill operations. Why on earth do you think that the manufacturers place the vent there?
I love to argue when I am correct ! Do as I say and clamp your vent at the top of the filler pipe and see how you get on. Text books are no substitute for direct experience.

[Oldiebut goodie]

By the way - the roll over valves are not in the filler vent pipe either!

[Oldiebut goodie]

Have a look at the way the manufacturer constructed it - not your textbooks.

[adie89]

None of which addresses the point as to why his fuel tank is inside the vehicle and under the bed.

[Oldiebut goodie]

It isn't. It was when he got the van. He has had a pukka fuel tank fitted. It helps if you read the first post! The thread isn't too long.

You appear to be having a great deal of difficulty understanding what has been written here - do you have some kind of problem causing this?
None of which explains your inability to accept how the filler neck is constructed - what textbook are you getting your erroneous information from as I would like to obtain a copy to amuse myself in a quiet hour.

[Oldiebut goodie]

I'm out - it is impossible to get through to some people.
Troopy - ignore all vents as per teacher. ( PM me and I will gladly assist you)