Fuel tank thingie

[MMeier]

When I top off my tank with the rig facing downhill, I get some fuel that leaks out from on top of the fuel tank module. Appears to be coming from a raised part that has an open end on it, facing drivers side of truck. Is this supposed to have a hose hooked up to it, or if just a vent , can I put a piece of hose over it and cap it? My first 93 never did this , so I never looked at the top of the module.

 

[bopplumb]

I have the same problem, fuel leak when fueling. It appears to be comming from the top of the fuel neck. I couldn't see exactly where though.

 

[MMeier]

Nope, my fill neck and vent tube are O. K. , they are toward the back of the tank. This is on top of the tank "module" , I believe they call it, a smaller round piece that appears to have a "vent" on it.

 

[Froadin]

It's supposed to be capped off. Mine came off recently and started leaking while filling the tank all the way up.

 

[MMeier]

It's supposed to be capped off. Mine came off recently and started leaking while filling the tank all the way up.

Just capped off, or hooked up to something I don't see? TIA!!!

 

[Froadin]

Just capped off.

Make note, when you cap it off, make sure it will be something that will STAY on there. Most plugs have a tendancy to just slide off after a while, even the stock parts do!

 

[MMeier]

O. K. , thanks for the info. Think I'll silicone a piece of hose on there with a plug of some sort.

 

[EZeis]

That's the roll over vent valve. I doubt you'll want to plug it. TSB 14-15-93 that fixes the problem by installing a hose on the valve and running it up along the filler tube.



Date: Sep. 24, 1993

Models: 1989-1993 (AD) Ram Pickup/Ram Cab Chassis



NOTE: THIS BULLETIN APPLIES TO VEHICLES EQUIPPED WITH A DIESEL ENGINE.



Symptom/Condition:



Repeated attempts to force fuel into the tank after the automatic shut off has engaged may lead to a condition where the fuel level in the tank is above the designed operating level. Fuel may leak out the roll over valve vent in this situation.



Diagnosis:



Inspect the vehicle for signs of a leak in the roll over valve area. If the condition exists, perform the repair procedure.



Repair Procedure:



This bulletin involves raising the roll over vent location by installing a section of fuel hose to the roll over valve vent nipple and routing the hose along the filler tube.



1. Cut a 43" section of the fuel hose listed above.



2. Install one end of the hose to the roll over valve vent nipple as shown in Figure 1.



3 . Route the hose along the fuel filler tube and strap it to the tube at the highest location possible, as shown in Figure 2.







Notes:



POLICY: Reimbursable within the provisions of the warranty.



TIME ALLOWANCE:

Labor Operation No. 14-40-20-90 . . . . . . 0. 2 Hrs.



FAILURE CODE: XX - Service Adjustment

 

[MMeier]

Interesting !! Anyone know what size this hose is? 1/8" perhaps.

 

[Moab4x4]

Bigger, I was just looking at mine today as I installed the tank wondering what I was missing.

I think it was 5/16. Might have been 3/8. I will check it out and report unless somebody beats me to it.

EZeis, Thanks for the VERY timely information.

 

[MMeier]

Mines a itty bitty thing, guess I 'll crawl underneath it tomorrow and see whats what. let us know what you figure out Moab.

 

[Froadin]

Mine is a much newer truck, but it's small as well, it would use a 1/8" to 3/16" ID hose I would say for mine.

 

[Moab4x4]

I think we are talking about different things. I downloaded this pic that I took. The big one is 3/8.



So do I guess correctly that we plug the big one and run tubing on the small one per the TSB?



What is the big port?

 

[MMeier]

I've been talking about the small one. Didn't notice the big one though, I'll have to take a better look I guess.

 

[Froadin]

Right, big one gets plugged, small one gets the hose per the TSB.

Although I just plugged the small one on mine, and that is what was on it before as well.



As for WHAT the bigger port is, I don't know. It is connected to a hose that goes down into the tank on the OUTSIDE of the big fuel module thing, and goes a little over half way down into the tank. It is almost like it's an extra return line, or maybe an alternate return line. No idea what it's for though.

 

[EZeis]

The bigger port maybe a option for a second fuel pick-up for onboard generators, compressors or such?? But the smaller port is the roll over valve vent.



Edit: I didn't notice what Froadins stated the first time around. The big port is a second optional fuel pick-up for generators and such. Since Froadins found the line goes half way into the tank, it makes it clear to me now. The optional pick-up only goes half way into the tank, so generator or such doesn't use all the fuel and you can still have fuel for the truck to get to a fuel station. Motorhomes use this with their onboard gensets.





Earl

 

[Froadin]

The line going down from the bigger port doesn't go all the way down though.

Of course it would be ok to use it for something that you DON'T want it to use all your fuel!

 

[Moab4x4]

Fuel reserve

Cool, I could just see using this like the reserve tank on my motorcycle if it weren't such a pain to bleed out the air. :-laf



It seems that it would be a great place to plug in a transfer tank for extended range.



Thanks for the info. I better go plug the big one.



Ken

 

[Moab4x4]

Small line is indeed 3/16. I got the line to do the TSB. Thanks again for the info.