Tank filling

[Christianfishn]

Been driving my cucv around as a DD and having a good time fixing something everday . Ive been putting this off because I never drive far but am tired of only having a couple gallons of diesel at a time. At first I could fill my tank to full, but after a little time the fuel would backup before the tank was at capacity. Now its gotten bad enough that I can only put 1 gallon in it at a time...
When filling diesel comes up out of the vent hole and "chuggs".
I checked the filler hose and the vent tube and replaced them and they are clear and clean. Does this make any sense< what could be keeping it from filling all the way?

 

[Rustyshackelford]

The diesel foams up and kicks off the pump. Pour it like you're pouring a beer and you'll have an easier time.

 

[tim292stro]

The angle of the filler neck inside your fuel cap can also trip the shut-off. I believe they call this the Beta Angle, more info in ISO 13331-1995. If there is a sharp turn in the filler pipe right inside the fuel cap, rather than a sweeping turn, a turbulent wave of fuel will form in the bend and trip the shut-off due to backing up the incoming fuel. With practice on certain vehicles I've noticed that I can turn the nozzle to point the tip a certain direction and prevent the creation of the bend's turbulence.

 

[cucvrus]

Are you using the extra big nozzle at the truck stop? I always go to the auto diesel pump. The nozzle is always cleaner and I don't end up smelling like I poured fuel on myself. I know you can fill it with the big boy nozzle. But whats the point if the small one does the same job without the hassle. I refuel one every other day for the past 20 years so I do have some experience. It is either a pickup or a Blazer. Both fuel fine at the auto diesel pump. And it keeps the truckers happy that I am not blocking the fuel island for a couple gallons of fuel. Win Win. Everyone happy happy.

 

[Keith_J]

ULSD foams like shaving soap. But the foam breaks down fast. Fill

 

[rustystud]

All the GM trucks of this era did this. Even gas models. Diesel is just worse since it foams when your pouring fast. On my M1031 I have to set there and hold the handle feathering it to get the fuel in.

 

[wheelspinner]

I have no trouble at all on my 1009. Just set it on medium and go. But as said above only on the auto diesel pump. The fast fill is, well, too fast.

 

[Christianfishn]

I have filled avoiding the foam aw well... I even went and got a 2 gallon gas can to pour it in. I know I have less than 2 gallons in my tank and even with the gas can one gallon is all I can get into it before it backs up with no foam at all....

 

[FloridaAKM]

My Deuce fuel tank does the same thing unless I take out the strainer & fill straight to the tank. If you run the auto diesel fuel nozzle slow with the strainer in, it will fill the tank, but when it get close to being full, it blows diesel foam all over the tank. OH well!

 

[CUCVLOVER]

Don't get mad.
Are you sure that the tank is not full when trying to add fuel?

Also which cucv is it?
Thanks.

 

[2deuce]

I have had tanks belch fuel if parked on an incline, but it sounds like your fuel gauge isn't working and your tank is full. The filler tube is the largest diameter I have seen behind a fuel door and attendants remark about that all the time. In Oregon you can't put gas in your own vehicle, diesel you can, but most don't and some stations can get upset if you do. So I just hand them the card and hang around to make sure they reach for the diesel and not gas. I think your tank is full unless it is damaged or someone swapped in another tank that doesn't fit right. If you have fuel standing in the neck and you have an original neck and tank that doesn't have something down there blocking it, your tank is full.

Since we can't see inside the tank, sometimes we think there is something going on in there that isn't. I bought an old 1956 International that wouldn't run the owner had tried everything, new points, cap and rotor, fuel pump etc and gave up. I tried the usual and found nothing was coming from the tank. It took compressed air to blow back into the tank. I thought someone had stuffed a rag or something in the tank as a prank. I fished around in there with a coat hanger but couldn't find anything. I was sure there was something, but I couldn't catch it. I drove the truck around a little, and it stopped again. Blew out the line, more fishing...no result. Decided to pull the tank to get that **** thing. What it was, was rust getting sucked up and plugging the line.

I bought a M1028 on GSA a few years back, they said it had all these engine problems and had been parked for 3 years. It was a beautiful low mileage truck. Perfect rust free body, I got it very cheap. Towed it home. Put in new batteries, opened the fuel bleeder on the filter to make sure it was getting fuel and smelled something funny, like gas. Smelled the tank and it was full of 3 year old gas. Sucked out 20 gallons of gas and she ran beautifully.

The moral of all this is that the fuel tank while not mysterious can be the source of many problems and yours points to the fuel gauge.

 

[Christianfishn]

Its a 1984 m1008.

Ive put 2 gallons in it, drove 75 miles, and could only put 2 gallons into it... if my tank if full then great! but i don't think it is... I can rock the truck back and for and hear a little bit of fuel sloshing around. When I take the filler neck off fuel comes out of the neck and the large tank nipple is filled to the brim. If I aggressively shake the truck then the tank will gurgle and I can ad an extra pint of diesel...

 

[Keith_J]

This is a real issue, I can squeeze in two gallons from initial handle trip to when diesel is visible. The filler neck hose is tapered and the tanks have vent lines. The foam doesn't flow as easily through the vent line and it causes foam to rise in the neck. Eventually the vent line purges and tank level drops.

It is all about the foam. Newer cars have a filler neck check valve to protect the vapor canister but CUCVCUCVs don't.

 

[2deuce]

Three things I would do, get something flexible long enough to run inside and gently test the neck for an obstruction, check the vent too. Next when filling your tank turn the nozzle upside down and have it look like a water fountain. You will get no foam, but you have to go slow or you will have diesel where you don't want it. I do this if I want to get in all I can. Last I would fill up a 5 gallon can and after you fill the truck all you can, take it to an incline with the nose of the truck downhill. Try adding the 5 gallons. Out of a can you should get very little foam or none at all.

 

[Recovry4x4]

For as easy as the tanks are to pull, might be worth the effort to have a looksee inside. If you have a boroscope, that might be an option as well if you remove the filler hose!

 

[2deuce]

They are easy to pull when empty, but we aren't to sure of that yet.

 

[crotchrocket81]

I say run it till it dies and carry a can or two of fuel with you. Simple and guaranteed results to know for sure.

 

[2deuce]

If you run out of fuel, getting it to run again on the side of the road can require lots more effort than pouring in a can of fuel. I would not do that.

 

[welpro222]

Its not too bad to re prime the fuel system, just make sure your batteries and starter are in very good shape.

 

[2deuce]

Make sure you run out of fuel where you have a nice place to park. If you run out on an overpass with no room to pull over, don't stop there go a little further where there is a nice wide spot.