Why does my truck take so long to fill at the pump?

My 1993 F350 idi takes forever to fill at the pump and I can barely squeeze the handle without it overflowing. I had to use a gas can the other day and had the same issue. It does it with both tanks. Is there a filter screen or a vent I need to check or is that just the way these truck are?

The venting sucks. There is a small ball valve looking vent on the top of the tanks that let no air out while fuel goes in along with poor filler neck venting.

There is a fast fill mod on here that works well, I've also took a 3/4" npt plastic pipe piece that fits in the rubber grommet and ran a fuel hose off of that up to the filler neck area but if your truck flips over the fuel would all spill out and make a fire way worse. I just drilled into the filler neck right under the fuel cap and put the hose back into there and jb welded it so the fuel would go back in which is essentially the fast fill mod just lazier if I remember right.

I think there are two filler neck designs, one for gas and one for diesel. If someone replaced the diesel filler neck with the gas style, they're more restrictive and increase the difficulty in filling. Sometimes this "swap" occurs without realizing it for example if the bed was changed out and the replacement bed was from a gasser...... The filler neck should be an assembly containing a hose inside of a hose. Fuel flows through the inner hose, the outer allows air to escape as you replace the empty air space with fuel during filling.
Another stumbling block and something I always look for when entering a fueling station is a diesel pump with the small diameter filler nozzle. The large ones designed for commercial trucks flow way too fast and create one heck of a mess.

The bed was replaced so I think that is the issue because it doesn’t have the hose within a hose. I use the small nozzle but it can’t even handle the rate of a gas can lol!

Do you know if the ones off my cab and chassis flat bed would work?

These are the ones I currently have

If you can find a diesel cab and chassis truck to get the fill neck from. Look closely at the top of the tank and see if you can get the vent and grommet from it as well. It is much larger and the primary piece needed to recreate the Transfer Flow style of fill necks that are no longer available. It’s almost 1” in diameter for the part that goes into the tank and 3/4” for the vent hose that parallels the fill tube up to the filler neck where it ties into the neck above where the nozzle rests while it’s filling.

Sounds good. The fill necks on my cab and chassis are both rusted out but I’ll keep my eye out.

Some pumps cause a lot of foam/bubbles which makes it back up, especially if they are slow starting.

I gave up trying to fill up at such a pump recently. I pumped about 6 gallons before I quit because it was was taking so long, having to stop and let the foam go down the neck.

I pumped enough to get me to another, cheaper station down the highway. That next station pumped just fine, no such problem.

Both pumps were the smallest diesel nozzle size you find, so it wasn't a commercial nozzle issue.

And the modified fill necks look something like this. You take a long punch or bar and knock the restrictor plate down and out of the neck. Then it’s big enough to take the bigger truck nozzle. You solder a fitting on the side like so to connect to the larger tank vent with 3/4” fuel rated hose. Make sure to route the hose so it doesn’t have any low spots in the middle so it can’t collect fuel and basically clog the vent return.

Anybody know the part number for the vent (little white plastic piece)...for a 93 diesel cab-n-chassis (Canadian manufacture)??

Hadn't been able to find a similar part at the yards round here.

Don't worry about the little white vent in the top of the tank. None of the roll-over valve/top tank vent designs from the factory are going to help with filling. They are just too small. Their only purpose is to let air in as the engine is using fuel out of the tank.

Like someone mentioned in a previous post, you should have a hose within a hose. With all that fuel going in from the fuel station nozzle, a lot of air has to get out at the same time. All this air as to be routed around the fuel coming in, or it will interfere and make the fuel splash and gulp and make the nozzle cut off.

Gas and diesel are the same. The earlier trucks (around 86-dwn) put the fuel into the large hose, with a smaller corrugated plastic hose in the middle that directed the air out away from the fuel going in. This was not the greatest design, and they changed it later to the fuel going down the smaller center rubber hose, and the air going up the large hose.

Since someone took your hose out of the center, you have a pretty bad situation, though even with the factory setup it was not that great. I had the same problems and tried many different things, what finally fixed mine for good was what someone mentioned previously, you take out the white roll-over valve in the top of the tank, and replace with a plumbing elbow that fits the grommet snug. I found a 3/4 copper L fits perfectly, and I soldered a short piece of copper to it, and then got some hose and clamped to that and ran over to the filler area. What I did was just run the hose up inbetween the inner and outer body cavity and tied it up with a screen over the end to keep the bugs out. It works great this way. If I let it fill to the top, sometimes I will get a little spot of diesel come out of the vent pipe at the station, but it's not much at all.

I would not worry about your fill pipe, I don't have the center one in mine now either, and it does fine with the larger vent hose coming out of the top of the tank.

Over the years, Ford figured out the fuel fill / vent on the trucks sucked. The did change them over they years.

The 2 bricks we had sucked..... I think I could have filled them faster with an eye dropper. One trick we found was to turn the fill nozzle "upside down" Where the trigger guard was facing the truck, and the rubber covered knuckle faced down. (opposite the way it hangs on the pump)

The 92 OBS was much better. You could actually set the holder on the first notch

My 03 Excursion (I do think tank placement does have some hand it this), I can use the bigger nozzle, and crank it open. If will fill as fast as I can send it. But this is a 44 gallon tank, in the very rear, and the fill hose is almost a straight shot to it.

Now jump ahead and change gears a bit, my 11 F-150 has the "capless fill" (There is not a removable gas cap, it has a sealed, latched trap door that is released by the fill nozzle when you put it in the fill hole). This one has a small vent line (looks a lot like and axle vent line) that is right by the drivers side rear leaf spring. This one will fill wide open, and I've only had it drip once or twice. SO even Ford has changed the tank to where it vents outside the fill neck. This is a midship tank, in a very similar location the the front tank on the IDI era trucks.

I modded mine as well, zero issues filling up.
the clear hose was replaced.

, like the "turbo hat" post, where were you guys a year ago? just went thru my fuel system, PO had a exhaust tube for rear tank and just rubber fuel hose straight up to flat bed,I didn't use rear do to FSV problems, so got everything straightened out and can't fill for crap,either tank, made up 2" fill tubes, new hose, and remounted with best angle I could get! guess PO took out inner tube stuff and/or pieced stuff together, front tank filled great when it went straight up to deck but was a hassle with a load. guess I
have to vent tank,harpoon it now! tanks only have the small roll over vent now.