BillLee

2004 F-150 Lariat w/5.4l engine. 30 gallon tank. Just under 90k miles.

Problem has developed the last two times I tried to fill the gas tank.

The fuel nozzle kicks off after delivery of only a small amount of gas. Can be as little as 1/4 gallon or occasionally as much as 4 to 5 gallons. I can nurse the nozzle and slowly get enough gas in to fill the tank.

Watching inside the fuel feed door behind the cap as I slowly add the fuel, I can see what seems to be a bit of gas moving in the area. I suspect the vent for the tank has become clogged some how.

Nothing has changed recently afaik, no over-filling of the tank, no work (ever) on the fuel system,... etc.

Suggestions?

Thanks.

Bill Lee

Bossgame

Mine does the same thing. I've always heard the ventilation is clogged too, so I figured it was just mud from off-roading. Be interesting to see what the fix is.

skoalking69

mine does the same. interested to see the solution.

screamineagle

Sounds like a venting issue however, the vent tube connects to the top of the fuel pump allowing the fuel to drain into the fuel tank. Unless you make it a habit to go off-road with your fuel door open, I don't see how the vent tube could become plugged. But anything is possible.

BillLee

Just spent a couple of hours of time from a tech at the local Ford dealer, found and corrected the problem: a mud dobber (wasp) nest in the vapor valve assembly as well as further up into the hose leading back to the carbon canister.

The unit apparently plugs into a hole in the side o the frame where there is atmospheric pressure. Also apparently there is a hole in the opposite side of the frame rail. And, as you might know, any open hole is a magnet for mud dobber wasps. They investigate and build their nests, big gobs of mud with eggs and paralized bugs to provide food for the hatchlings.

Picture shows the plugged part after it was removed from the frame and before it was cleaned. The diagram is for something, probably not my 2004, but similar.

Hollabakzach23

Interesting! Mine did this once or twice when I first got my 04 but hahas never done it since.

TonyC1

Your bug died!

kl01721

BillLee, I have the exact same problem. Can you give me a little more detail about where to find that vapor valve assembly? I just bought an 07 a couple days ago and found a couple dirtdobber nests hiding in a few places so I have a STRONG feeling that whatever fixed your problem will fix mine without spending an arm and a leg at the Ford Dealer for them to do the same thing I could do

BillLee

I wish I could be more help, but I haven't crawled around underneath myself to look. Best I can offer is that the mechanism in question is nearby the tank, in the frame rail on the driver side (I think) and forward of the tank.

From the description that the service tech gave me, it involves some tubing (probably rubber) and the tank itself. The picture shows the plugged unit. It appears to be large enough to be easily spotted when you crawl around underneath.

Mod (Ret.)

Very helpful post and pictures. I always thought though that any issues with the evap system would set a CEL code.