I solved the slow fillup problem on my '03

[Spooled-up]

SReaves,

Where exactly did you tap into the main vent line? I made sure to tap into it as high up as possible. Thinking about it, I wasn't sure if it would work if it entered the main vent line below the top of the tank. It's only flowing air, so it might work if I put it lower on the vent line. This would eliminate the 3/4" to 3/4" hose coupling and further reduce the cost of the kit.

 

[SReaves]

Spooled-up,

I spliced into the existing rubber vent hose just above the curve and just below the metal tubing that goes to the filler neck. Use a 3/4"X3/4"X3/8" tee. The hose says it is 3/4" on the outside but the fittings were a little loose. I just tighted the hell out of the hose clamps and it seams to be sealed. No leaks when filled up above the vent tube in the filler neck. Thanks again and let me know if you need any info.

 

[Spooled-up]

Thanks SReaves,



That eliminates one more brass fitting.



I'll have to redo mine so I can clean it up with the new kit. Off to get some hose and clamps so I can get the price for you guys.

 

[Spooled-up]

I've got a price worked out for the kit. It should appear in the Classifieds under Vendor promotions / Basement enterprises once approved by the webmaster. I don't think I'm allowed to post the price here.

 

[yogibear]

The bed is off my trk. , and mine has a vent in the front of the tank, about 4" back, and a vent in the back high part of the tank. There are no hoses on either of the 90* barbs. Shouldn't there be hoses on both of them? I have never had any trouble filling my tank, can only get maybe 1/2 gal. in after the pump shuts off.



Larry

 

[Spooled-up]

Larry,

Are you talking about the small 1/8" vents forward and back? If they don't have a hose on them, I don't think they are actually venting your tank. I still haven't figured out what they are for. Maybe something to do with the manufacture of the tank. I tried to blow into one of the small barbs and got nothing.



When you fill your tank, do you fill it so fuel shows at the fill neck and stays there? If it does, consider yourself lucky. The people with the slow fill problem can get 3-5 gallons in after the pump clicks off.

 

[Crunch]

the 1/8" "vents"

Originally posted by Spooled-up

Are you talking about the small 1/8" vents forward and back? If they don't have a hose on them, I don't think they are actually venting your tank. I still haven't figured out what they are for. Maybe something to do with the manufacture of the tank. I tried to blow into one of the small barbs and got nothing.

Any chance these could be where the injectors were attached when the tank was injection molded?

 

[Spooled-up]

That could be true. Not sure how that process works, but that could be the reason for the plugged barbs.

 

[yogibear]

I don't even try anymore, have tried several times, and never able to get more than . 3 or . 4 gal. till its in the filler neck, and stays there. I'll have to check those barbs that look like vents, to see if they do vent.



Larry

 

[Spooled-up]

kit is in the classifieds.

I should be able to ship these by monday at the latest. Hopefully friday.



Vent kit

 

[PKitchen]

Spooled-up, have you thought about creating an account at PayPal.com? Payments would be much easier than personal checks. Just a thought.

 

[Spooled-up]

PKitchen,

I'm going to look into that right now. Is there a charge for that service? Thanks.

 

[PKitchen]

No charge to set up the account at PayPal. Buyers can then use their own PayPal account to send you funds via their checking account or credit card. There's a small fee when a credit card is used though. PayPal is very popular and is used for most transactions on EBay.



Thanks for your good work on this modification and putting together a kit.

 

[PKitchen]

I'm considering doing this modification myself but the possibility of leaking fuel has me concerned.



Diesel has a 0. 00046 1/*F coefficient of thermal expansion (Diesel Coefficient of Thermal Expansion). I did a few calculations for the worst case scenario. Underground fuel tanks are typically at a constant temperature of 50-55 degrees year round. Let's say you fill up with 38 gallons of fuel, then immediately park your vehicle on asphalt. Let's say the hot asphalt causes the fuel in the truck's tank to reach 105 degrees. Multiplying 38 gallons by 0. 00046 by 50 degree change gives 0. 874 gallons. So potentially the fuel could expand enough to overflow the tank by 7/8 gallon of fuel. The simple solution is to burn off some fuel before letting the vehicle sit. Of course when the air temperature is below 55 degrees there wouldn't be anything to worry about since the fuel would contract rather than expand.



I'd be interested to hear of any problems from those who have made this modification. Keep us posted.

 

[Matt400]

Originally posted by PKitchen

the fuel could expand enough to overflow the tank by 7/8 gallon of fuel.

The material of the tank will bulge that much for sure and even without the mod I bet that space still holds the air pocket their while the fuel expands.

 

[klenger]

Considering that summer air temps here get to about 110* (in the shade), the expansion gets even worse.

 

[Spooled-up]

Where will the fuel go if it expands. Is our fuel cap vented? I'm not sure because of the fuel return line from the fuel injection system. Is the cap only taking in air and not letting it out?



The reason I'm not concerned about this is that I've been filling my tank this way for a year now. If I do fill up and drive right home, the truck goes in the garage and is not exposed to very high temps. This coupled with a 4 mile drive from the station burns off enough fuel that I haven't had a problem.



PKitchen,



Thanks for the info on the expansion. I was curious about that.

 

[PKitchen]

Spooled-up,

Taking your situation, let's say your garage is 80 degrees in the summer. If you get 16 MPG for your 4 mile trip from the gas station to home, this would burn . 25 gallons. 38 gallons would expand by . 437 gallons with a 25 degree temperature change. Since your fuel is expanding by more than you burn off, it must be going some where. Maybe the vent line holds enough of the expanded fuel. Or maybe as others have said the extra pressure inside the tank expands the tank enough to hold the fuel.

 

[Matt400]

Re: Larry,

Originally posted by Spooled-up

Are you talking about the small 1/8" vents forward and back? If they don't have a hose on them, I don't think they are actually venting your tank. I still haven't figured out what they are for.

Those are used in the gas trucks. They are check valves to permit fuel vapors into the charcoal canister and not raw fuel. The gas trucks require a closed system so those barbed ends have a hose attached and then go to the canister.



My guess is what you see on our trucks is one that looks like a check valve but is a dummy that is not functional to plug the hole. I am sure they use the same tank for gas and diesel.

I might throw a vacuum pump on there to see what happens just for fun.

 

[Spooled-up]

Maybe the vent line holds enough of the expanded fuel. Or maybe as others have said the extra pressure inside the tank expands the tank enough to hold the fuel.

It must be one of the two, because I haven't seen a drop of fuel anywhere on my floor. No diesel smell either.



The tank sides and bottom are pretty flexible as is the top of the tank. I'm sure they expand enough to hold . 8 gallons.