LML Won’t take fuel in tank

[LBZ]

Well for some reason all of a sudden my truck has stopped taking fuel. I have not done anything to the vent hose in the filler neck and to tie in my airdog and my slip tank I welded a fitting into the top of the filler neck but that was 2 years ago and it’s been fine till now. I didn’t molest the filler or vent hose at all.

Only way I can fuel it is by pumping it in from my slip tank.

Basically when I try to fuel it at the pumps it fills the filler neck immediately and stops. So does anyone know what’s in the filler or filler neck vent hose that could cause me grief? Screens or anything?

 

[Chevy1925]

Just a plastic liner that runs down the rubber hose. Maybe it split or is kinked?

 

[FC5452]

Take the vent tube off the filler neck and drain it, you have a pocket of fuel in it.
The vent hose has a say in it before it hits the top of the tank.


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[darkness]

My lb7 had that problem. But it was hit or miss. I used to just hold the nozzle just in the fuel neck and it would work. I’m sure that’s not what you want to do in the Canadian cold though :rofl:

 

[LBZ]

I was planning to take the vent off and blow some air through it and see what happens whenever it warms up enough outside to do it. I know the fords have a screen in the filler neck that can plug up but my fuel is pretty clean and filtered to 20 micron before it even gets put in the tank so I’m sure that’s not the problem. No kinks that I could see.

It’s not a slow fill issue it’s a no fill issue. I can see the fuel slowly going down the filler once it clicks off and Ralph’s fuel down the side of my truck.

 

[2004LB7]

Can you put a rod or something down the filler to see if there is anything in the way? Look down it With a flashlight?

 

[clrussell]

Sounds like the vent is plugged as mentioned earlier. I can easily see this with an in bed tank.

There’s nothing in the main filler hose to my memory.

 

[LBZ]

Can you put a rod or something down the filler to see if there is anything in the way? Look down it With a flashlight?

As far as I can see there is nothing. I can try to jam a fish tape down it and see if there is anything in there.

 

[LBZ]

Sounds like the vent is plugged as mentioned earlier. I can easily see this with an in bed tank.

There’s nothing in the main filler hose to my memory.

How would the in bed tank plug the vent?

 

[gmduramax]

How would the in bed tank plug the vent?

Over filled it.

 

[2004LB7]

Over filled it.

I've "over filled" mine for as long as I can remember. No issues as of yet

 

[gmduramax]

I've "over filled" mine for as long as I can remember. No issues as of yet

Me too. But if for some reason the vent hose has a section where the fuel can’t drain out that would cause the problem he’s having.

 

[2004LB7]

So could one pressurize the tank with a few psi of air for a few minutes and clear it without having to drop the tank or lift the bed?

 

[FC5452]

Did you pull the 1” vent hose off the filler neck and pull it out of the frame and drop it down yet Nd empty any fuel trapped, its a vent issue


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[LBZ]

It’s been -10c for a week so I haven’t touched the truck yet. I’ve overfilled this truck and my last two as in fuel running out on the ground lol many times with no issue.

This problem started in the fall though and I thought it would just sort itself out but no. And I haven’t overfilled it in a year.

I’m going to pull the vent off and blow air into it with the cap off and see what happens.

 

[FC5452]

My 2011 had been flawless for 7 years filling at truck stops, then this past summer I went to fill up in South Carolina and only got 10 gallons in when the truck was on E.

Went to another station with regular nozzles Nd the same thing. Asked a good friend who’s a master tech, and e said the same thing to me, pull the vent and drain it out.

I did and haven’t had an issue since, Over filling it causes the fuel to trickle down the vent, that hose droops between the frame and tank, it acts Ike a trap on a sink, finally the fuel fill the trap, no air in or out. Fuel can’t vent and up the fill neck it goes and shuts the nozzle off.


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[2004LB7]

Are we talking about the vent hose that runs up along side the filler tube and connects up near the cap?

If so, this is where I've connected my in-bed tank to and have filled my whole stock tank up with through this without any issues.

Or is it another one I've missed?

Another possibility is that the vent tube has kinked, likely at the bend on top of the tank

 

[FC5452]

That be the tube, and yes that could be the culprit.


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[LBZ]

I don’t know why it would kink as it hasn’t been molested in that area ever and should be as it was when factory installed.

I feel I may have tied in and used the vent to fill and also run my fass return in my ‘07 for awhile and it restricted the vent so I couldn’t fill at wot but at least it still filled at 1/2 throttle at the pump. I eventually welded a fitting in as I did to this truck and no issues.

One thing I did notice as this time when I welded the fitting in I didn’t tip it down as much as I did on my ‘07 so maybe it’s splashing down the vent line? Another thing that just occurred to me is the problems started when I installed my airdog. Maybe when I transfer on the fly the extra flow is in fact splashing hard enough at the vent it’s filling the vent up???

Gonna mess with it Monday if it’s not too cold.

 

[LBZ]

So to follow up on this, the fuel from my slip tank and airdog return are indeed going down the vent line and causing it to not vent. I blew air through and cleared it and could fuel it fine. A revamp of the filler neck is in order I suppose.