Slow fuel fill issue

[Kopykat]

As anyone resolved this issue? I'm not talking about removing parts and cleaning every year because the issue comes up over and over.

I'm talking a flat out "FIX" so then you can walk away and forget about it.

I've heard rumor of the vent line clogging. I've pulled mine apart from the tank to the fill door and it's clear/clean.

I have put air pressure into the tank and the air comes out the vent line.

Now after being under the truck I can see a couple issues right off the bat that is just flat out poor design.

1. The filler neck tapers down to about a 3/4" line just after the fill spout. With this being about the same size as the pumps nozzle, this could cause back pressure, thus triggering the pump to click off.

2. the fill on the fuel tank is at the bottom of the tank. Think about it...the weight of the fuel is pushing back on the fill hole. compounding to the fill restriction in the neck.

http://www.engineeringtoolbox.com/static-pressure-head-d_610.html

Nearly every efi fuel system I have messed with the tank setup has always been the same. The fill port is on top of the tank allowing the fuel to fill the tank with the help of gravity. The explorer setup seems to rely on the fuel nozzle pressure to fill the tank, but yet nearly all the fuel stations have the feedback sensor to stop the fuel from over filling the tank.

Anyone else on the same page here?

To truely fix the issue the vent would need to be as large as the fill so that the air displacement from the fuel is allowed to escape at the same rate the fuel is being forced in. but the weight of the fuel on the fill hole which is at the bottom of the tank will always push back the fuel.

 

[pzy3339]

Vent does not need to be the size of the fill. Liquid(gasoline) resists movement much more than a gas(air) does.

The fill from the bottom versus the top does not reduce the effect of gravity either. If you need proof of that, its a physics issue so start there. I would consider it beneficial since the gas does not rush in and hit the surface of the tank, likely reducing vaporization, plus doing it this way means no vapor will come out the fill neck, it will only come out the vent tube. This makes it more controlled and the gas pump can be designed more effectively to contain the vapor.

I had this issue happen once, for 3 tank refills and it fixed itself. Could hardly pump gas at all, I would hold the pump just at the opening to the neck, and it would overflow if I went too fast! Pretty annoying.

While having the issue I looked into it, there was a vent tube redesign.

I believe the issue is the tube has a low point that gets stuck full of fuel somehow and makes itself act like a trap (like on your sink drain) preventing any venting.


Look up the service bulletin. There is a procedure for the whole thing. I found it all on here, just search around.

Maybe you can alter yours, or even make your own to fix the issue? Good luck.

 

[swshawaii]

FUEL FILL - SLOW OR EARLY SHUT OFF
http://www.revbase.com/BBBMOTOR/TSb/DownloadPdf?id=140577

http://www.bbbind.com/free_tsb.html