RDS Fuel tank/toolbox

[RandyDeb]

I just installed a RDS 60 gal fuel/toolbox combo in my 08 F350. They call it a 60 gal tank, but it was full at about 54 gal. Not sure if I was level or not, but it looked to be close. I then drove about 100 miles to move a few things. I figured the fuel would stat to transfer as soon as the 35 gal internal tank started to empty. But it didn't. I don't think it transferred any fuel at all. The valve and vent are both open. Managed to have a little fuel in the box I believe came out the vent. Plan on putting in a second 90 degree elbow and a short peace of hose to see if that will keep fuel from coming out of the vent. The tee pipe that is cut into the fill hose is laying as flat as I could get it. I believe that more for the ball float to shut off fuel flow. I do have a small sag in the hose between the hole in the box and the tee pipe, maybe an inch give or take. Don't know if that is an issue or not. Both the tanks were full when I started, Internal tank is showing about 3/4 now.

Any ideas on what the problem could be?

 

[jleavitt11]

I installed a 90 gal RDS on my new 2017 F350 and I thought I had the same problem. It turns out it tricks the fuel gauge somehow. I filled the truck tank then filled the transfer tank ( 90 gal tank only held 81 gallons). I started driving thinking the gauge would show full untill the transfer tank was empty. My fuel gauge just kept dropping. I thought the line was plugged or something. I unscrewed the fill cap to see if it was full and it poured out into my driveway. No doubt it is full even though the gauge shows 3/4. Once the fuel gauge got to about 3/4 it just reset itself somehow and jumped to full. Im not sure what is going on but perhaps you have the same problem. If anyone else knows what is going on please let me know.

 

[jnbhobe]

I have the same setup guys, I do use a solinoid to shut it off if I want to. 60 gal tank took 54 gal to fill and you will never get more than 50 gal in it again. Mine does work perfectly, stays on full till yhr first 50 is gone then goes down as used.

 

[RandyDeb]

I left the truck set for about an hour, then went to get the camper out of storage. When I started it up the gage said full. Not sure why it didn't reset after shutting it off, but maybe it won't reset until it gets down to 3/4 of a tank on the gage. No fuel on the ground (yet).

Thanks for the info....

 

[Oregon_Camper]

I don't have your brand, but on my (even with a pump) it takes a long time to get fuel into the main tank. My guess is your fuel is following, but just too slow to see it in real time. My system takes 30-45 mins (while driving) to go from 1/4 tank to Full.

 

[RandyDeb]

Yes, its not are real big feed line. Maybe 1/4" ID. Just hopping to not go out to a big fuel spill on the driveway in the morning. Any body know if that tank has a baffle in it? Apparently the computer doesn't look for the fuel level to be going up or staying the same while on the move, but will read the fuel level again when it gets down to 3/4 of a tank. Then thinks the tank was filled again. Its not addressed when doing a tuner when your asked about tire size, cold air intake, DPF and EGR removed, yes or no. It would have to ask if an axillary fuel tank has been added. Then it would know to look more often.

 

[coram8]

I have the same setup guys, I do use a solinoid to shut it off if I want to. 60 gal tank took 54 gal to fill and you will never get more than 50 gal in it again. Mine does work perfectly, stays on full till yhr first 50 is gone then goes down as used.

I have the RDS 60 combo on my GMC. It has the manual inline valve to open or close it off. What kind of solenoid do you have to control yours?

 

[jnbhobe]

12V from STS Valve hooked to an upfitter switch

 

[cookie]

I left the truck set for about an hour, then went to get the camper out of storage. When I started it up the gage said full.

Was the valve from the tank open during that time?
My aux tank just barely fills faster than what I use from the OEM tank.
And yes there is a baffle in the RDS tank.

Peace
Dave

 

[RandyDeb]

Yes the valve was open. It all seems to be work like it should. I left the truck set outside the first night just incase something would start leaking. Didn't want to have to give my wife a good listing to because the house smelled like diesel fuel. I would like to replace the 90 degree elbow on the vent with a ball valve that won't let fuel spill out the vent when its full. I would have preferred the 90 gal (should I say the 81 gal) tank and not have the tool box, because you can't get anything in it anyway. The good thing is I can get my tonneau cover over the 60 gal tank when I'm not towing.

 

[cookie]

I would like to replace the 90 degree elbow on the vent with a ball valve that won't let fuel spill out the vent when its full.

If you install a ball valve and close it off you probably will not feed your OEM tank. It will create a vacuum. You need a vent.

Peace
Dave

 

[porthole]

I would like to replace the 90 degree elbow on the vent with a ball valve that won't let fuel spill out the vent when its full.

The 90 degree elbows on the tank and the trucks fuel fill hose Tee are rollover valves. I would not put a ball valve in there.

The fitting has a float ball in it. For the tank, in the event of a rollover the ball will float into a seat (at the threaded end) and prevent fuel from spilling. On the truck the ball floats (into the nipple end) when the fuel filler hose is full to stop the auxiliary tank flow. Useful if someone takes the cap off

Putting a ball valve on the vent will give almost zero flow of fuel.

On my truck I ran the vent up as high as it would go and over to a catch bottle mounted on the bed sidewall.

 

[chaplady]

Duane when we cross paths again I'd like to see your vent set up. I'm interested in seeing how you did this. Thanks Bill

 

[RandyDeb]

I miss spoke when I said Ball valve. I should have said Rollover valve. After reading some of your inputs I'm going to try two 90 deg elbows with clear 1/4 hose so I can see if I have any fuel in the line. Plan is to have the first elbow turned mostly forward and upward with enough hose on it to get to the front of the tank. There is a fitting with a plug in it on top of the tank a few inches from the left side. I'm going to zip tie the vent line to that plug with the second elbow turned down into a catch can or bottle. Hope is to control the fuel getting into the vent line. The hose just needs to be high enough and long enough to catch the "splash" of fuel that happens when the tank is full. If the angle is right that fuel would end up back in the tank.

 

[porthole]

Duane when we cross paths again I'd like to see your vent set up. I'm interested in seeing how you did this. Thanks Bill

Not much to it Bill. An empty RV holding tank treatment bottle and a plastic clip from the boat store. Drill hole in the cap and stuff the vent line in.
My vent hose runs as high as possible and then into the bottle.

If I fill the auxiliary tank to the max and then the temp picks up 20 degrees, I will occasionally get fuel in the bottle. Pop the bottle and dump in the main tank and good to go.
It took cleaning out the pickup bed twice before i did this.

Rumor has it there is a certain brown Super Duty running in New York that has a similar setup.

 

[Bones]

Not much to it Bill. An empty RV holding tank treatment bottle and a plastic clip from the boat store. Drill hole in the cap and stuff the vent line in.
My vent hose runs as high as possible and then into the bottle.

If I fill the auxiliary tank to the max and then the temp picks up 20 degrees, I will occasionally get fuel in the bottle. Pop the bottle and dump in the main tank and good to go.
It took cleaning out the pickup bed twice before i did this.

Rumor has it there is a certain brown Super Duty running in New York that has a similar setup.

If you put the hose all the way down to the bottom just about when it spits fuel from heat it will suck it back in when it cools down.

 

[porthole]

If you put the hose all the way down to the bottom just about when it spits fuel from heat it will suck it back in when it cools down.

Doesn't work. The bottle is higher then the tank.

 

[Bones]

oh well

 

[porthole]

oh well

Since we're talking with the engineer here - I'll qualify the "it doesn't work" comment.

"If" the truck was stationary it would probably work, going in the bottle under pressure and siphoning out as the tank cooled.

But, being on the truck, the fuel doesn't stay in the hose for the siphon effect to work, bouncing, stop & go etc's.

 

[Bones]

Since we're talking with the engineer here - I'll qualify the "it doesn't work" comment.

"If" the truck was stationary it would probably work, going in the bottle under pressure and siphoning out as the tank cooled.

But, being on the truck, the fuel doesn't stay in the hose for the siphon effect to work, bouncing, stop & go etc's.

Thanks but you could always modify the set up to a somewhat sealed system. have a fitting and turn your catch can upside down so your air is at the top and your vent line comes in from the bottom. So as expansion happens it pushes air or fuel up the line into your bottle then when cooling the line can either suck it back down or gravity will pull the fuel back in. Just make sure you have a small vent at the top of the bottle.