Aux. fuel tank and venting ?

[jhurst]

Hi all... .



I just got my aux. tank hooked up, that I purchased from another TDR member, using a spare 24v lift pump and a racor filter.

I have the setup "T"ed into the vent hose of the main tank. The aux. tank vents through a venting cap on the tank.



Everything is working fine but the main tank builds alot of pressure when the aux. is turned on.

Are there any ill-effects that may be caused by this? I'm thinking that maybe the fill cap on the main tank is just starting to vent at that pressure.

Should I run another line from the vent line on the main tank up to the aux. to vent the main tank?



On the flip side, I have gained about 2psi fuel pressure post filter while idling and cruising when the aux. tank is running and pressuring the main.



Thanks in advance for your help!!



Justin H.

 

[Wiredawg]

Why?

Why tee into the main tank vent when the cap is vented? I have an Aux Tank on my dually and it is vented with a ball valve and hose out of the top of the tank. I recommend eliminate the tap off of the main tank.



My two cents,



Wiredawg

 

[jhurst]

Thanks for the reply.



I think I may have described it wrong. The fuel from the aux. feeds the main tank through the T in the vent line of the main tank. It is not a vent.



My question is if main tank is being pressured too much (such a thing?)

Should it be vented (like a line from the vent line of main tank to the aux. to equalize the pressure in the main when fuel is being pumped into it)? But shouldnt the main tank vent fine through the fill cap?

OK now I'm confusing myself. I think I am rambling about nothing.



Thanks



Justin H

 

[BigDaddy]

Justin,



Even after your explaination, I am not exactly sure where you have tapped into to feed the main tank



I am sure about this, our main fuel tanks are vented tanks. So, if you are building pressure in the main tank, something is wrong



If you have not tapped into the tank vent, check it to ensure it is not blocked.



Just my . 02

 

[jhurst]

The aux. feeds the main tank through a "T" in the vent line of the main tank. Pretty much like Gary - KJ6Q 's setup in this pic.

 

[cpo223]

aux.fuel tank

Justin,

I read your post regarding the aux. tank. I too would like one,&am studying what's the easy,simplest way to do it. I want a tank that holds about 30 to 50 gals. & is removable. I wonder if your main tank pressure build up is due your blocking venting w/fuel when your filling the main tank from the aux. ?I have looked up at the vent & fill hoses 0n my 2003,I guess it's same on all years? This is prob ally all real simple to a mechanic. One problem I've run into, is that no seem's to want to install aux. tanks around my area(liability?)

Have you put a electric switch,(solenoid?)So you can stop transfer, in this unit?I want the tank removable so I can use it only while towing. Please keep me posted as you progress with your fuel system. Pat

 

[jhurst]

PCoakley,



I thought about the vent line being blocked by fuel too, but I believe if it was, it should still be able to vent through the fill neck itself.



My fuel tank holds 45 gal and is 10" wide by 19" tall and 57" long. It takes up 12" of bed space across the front.

I have mine setup using a solenoid valve (from NAPA, used to select between two fuel tanks) to turn the flow of fuel to the pump on and off. You can view some pics of my setup here



I'm not sure if the 03 trucks are the same but I bet they are pretty close. The very simplest way to hook up an aux. may be to just gravity feed it through a solenoid valve to a "T" in the vent line. There are several members that are running their's that way. As far as making it removable, you could some type of quick-connect such as hydraulic couplers. There has been a recent post about installing a removable tank here.



Feel free to PM or email me if you have any questions or want some more pics. Oo.



Justin H

 

[illflem]

I don't think you have a problem. The 2 psi gain you have in FP indicates to me that the stock tank's cap is relieving pressure just as it was designed to - at 2 psi.

 

[cpo223]

aux.tank

Justin,

great pics on your site!I wonder if you could transfer better if you t-ed into the main tank's fill hose,rather then the vent hose?the quick dis-connect fittings are a good suggestion. you pretty much have what i want in your tank system. in having a tank made, the welder asked if i would want the tank to flow from the bottom,or have a pick-up tube from the top. i'm not sure which would be better. i'm also looking at tool box tanks. pat

 

[jhurst]

Thanks illflem, just what I wanted to hear.



PCoakley,

A toolbox tank would be nice. I wanted one, but since I have a shortbed, didn't really have space for it.

As far as top and bottom, if you are going to use a pump in your setup, it won't really matter which. It might be safer to have it at the top incase a fitting or line gets knocked off, all the fuel wouldn't drain out. If you are going to gravity flow to the main tank, then your best bet would be in the bottom.



This is a good picture of Gary- KJ6Q 's setup. You can see the valve on the right, the pump, and filter.



Good luck



Justin H