As the title says, I recently replaced the fuel pump and drivers module and from the first attempt to fill up after about 1.00 in gas it back flows up the filler tube. Blew compressed air and it sounded as it should. Tried disconnecting the EVAP line next to break booster while filling up and no change. Dropped the tank this time (the bed was full) and made sure no kinks in the lines. And I did find a small piece of plastic on the scree in the fill tube but no luck, it wasn't the culprit.. I did however take a picture of what appears to be vents in the tank. Could these be the culprit or anyone have a suggestion? It takes forever to fill the tank. Again it started from the minute I replaced the fuel pump and driver fuel module. The pic is below. Man I hope someone can help. Going on a road trip and will have to add atleast an hour just for refueling. Oh another thing it doesn't backflow if I use gas cans and I did notice that the stations with the real fast pumps it takes a little longer before it happens if that tells someone something.

 

You pulled the bed the first time to replace the pump? I'd guess that the filler neck vent hose is kinked or pinched

 

Just a curiosity -
When I look at your photo it appears the view is the inside of the gas tank. Its been a while since I did a fuel pump or a gas tank replacement but there are generally three or four sensors that need to be reinstalled in the top of the tank once the pump is installed, your photo shows one of those sensors. From the photo it appears the sensor is just hanging in the tank well past its locking tabs and seal ring. Is your sensor installed correctly?
Back to your issue with filling the tank - Did you ever get that figured out and corrected?

 

Those sensors are mounted on the inside and when you feel them they seam tight. Someone suggested the filler tube may be kinked but sadly it's not the issue. I'm stumped on this one because I've tried all the suggested tricks and the issue is still the same. Took me 20 minutes to fill up from a quarter tank yesterday. The only thing left would be the check valve sticking at the bottom of the fill tube. That seamed very loose and movable and the spring was not a very tightly coiled together and did get a little off center but it doesn't seam like that would stop the flow of a gas nozzle. I'm not sure if I did this before or after I posted this but my brother has the same truck and I took his purge valve (I think it's called) located next to brake booster and swapped them and went to fill up and that made no difference.

 

Please describe your year, make, model.
Do you have any Diagnostic Trouble Codes (DTCs) stored in your ECM. Pending codes may have not, as yet, set a Check Engine light. You should check for these or go to Autozone (or similar) and get them checked to see if there is an issue with items that vent the gas tank to the charcoal canister. From what you have said it sounds like the tank may be having a venting problem. Check and make sure you reconnected the electrical connectors to the vent valve.
I did some web searching and some (very few) have found the problem to be a charcoal filter that is filled with gasoline presumably from over filling the tank. Most of the problems have been kinked filler hoses (you have already checked that) and pinched or kinked vent hoses.
Give us feedback on these questions and maybe we can stir up other possible solution paths.
Anybody out there have a diagram of the emissions (charcoal canister, etc) for a 2004-2008 F150? I need it for nomenclature and to enlist other comments.

 

Sorry for the late response I've been traveling.
I have an 2007 STX special edition with a 5.4L flex fuel engine. I have my own OBD2 code reader and there have been no DTC codes or any pending during this process. When I dropped the tank this time I did a complete inspection of the hook ups and even reached the clips on the end of the houses/lines on the fuel pump. The only thing I forgot to do was check all the lines in the tank for problems. I got some very bad news and had to put the truck back together asap.

 

Your vent line thru the carbon cannister is blocked. there is a vent valve that's normally open except when pcm is pulling a vacuum test on gas tank system . Mud , insect debris or a clogged carbon cannister . You need to remove this vent system to see where the problem is . pull the bed and check it out . There is no vent line on filler . Air must go out when fuel tries to go in or pressure will rise rapidly in tank . Stopping fuel going in . .
This is a classic symptom of a bad vent system . Do you go mudding ?

 

There IS a vent on the filler tube and I would be looking at it if you had no problem filling up before. It's the smaller like 1/2” tube that runs parallel to the filler neck and tees into the filler neck about 2" from the top end. The rubber hose coming off it is what I'd look at.
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Or here is another place to look in this thread
https://www.f150forum.com/f4/fuel-ta...roblem-279952/

 

No, I've never takin my truck mudding, it's only a 2WD and I was raised in the suburbs and the city. I did check one vent line for bees, wasp's etc. There is a small vent line that runs right up the filler tube ends about 2" from the top intake. It's still bothering me with the timing of the issue. This crap started the very first fill up.past the fuel pump install.

 

I used a large stand up air compressor and pressurized the tank several times and it flowed pretty good.