Aux Fuel Tank Plumbing

[CToney]

I have a Fuel Tank tool box combo that I had custom built for my '93 originally and used it in my '97 as well. I have never plumbed in the fuel tank on my '03. I have heard that there is an auxillary port in the fuel tank module. Can I plumb into this or should I T into the FASS return line. What size is the Aux fitting on top of the tank?



On a couple of recent trips I have had touble getting to a fueling station due to high winds reducing my fuel economy. I should have done this a while a go but now it seems to be a necessity. 40mph winds seem to lose me ~75miles per tank and increase my boost from 10-15psi to >20psi @ 65 mph.



Thanks

 

[steved]

Remove the manifold for the FASS (the steel "T" in the filler line the FASS uses for a return)... drill and tap that for a 3/8" barb by 1/4" NPT fitting and your tank will gravity feed. I've had mine this way for several years.

I would not "T" into the FASS return line as it may have enough pressure to back feed into your auxiliary tank.

 

[HBarlow]

I don't know about Canada but USDOT prohibits gravity flow aux fuel tanks.

Does that mean people don't use them anyway? No.

 

[Superglide]

Good morning, Harvey. As far as I know, gravity feed is fine for diesel in Canada but gasoline is not. I'll try and confirm this.

 

[Superglide]

Yes, gravity fed auxiliary diesel fuel tanks are DOT approved in Canada.



Northern Tool - RDS Auxiliary Fuel Tank/Toolbox Combo — 60 Gallon, Model# 72644 customer reviews - product reviews - read top consumer ratings

 

[Shadrach]

I don't believe gravity are allowed on "commercail vehicles "as a friend who hauls RV's from the US to Canada wasn't allowed to do this. I don't know which country told him this, but he did have to have an electrical solenoid on it. My truck currenty has a gravity feed on it but I've never used it. Personally I would prefer the electric version. What happenes if some opens your fuel cap? Shadrach

 

[CToney]

Thanks for the help guys. Removing the fast T should be easy. Tapping it should work great. I believe the gravity feed is ok up here you just have to have TDG sticker on the tank or have it painted red.

 

[BLNRAY]

gravity feeding an aux tank is also a good way to check your factory fuel tank vents,should one of them stick open you will find a pool of diesel under your truck

 

[HBarlow]

gravity feeding an aux tank is also a good way to check your factory fuel tank vents,should one of them stick open you will find a pool of diesel under your truck

... ... ..... or trailing behind you for many miles.

Can you imagine the outrage some lib might express if he or she observed an evil diesel truck trailing diesel fuel from one town to the next?

 

[CToney]

Simmer down Margaret.



I only ever turned on my valve from my aux tank when I was parked and only when I knew the contents of the aux tank would not overfill my main tank.



I am glad I live north of the 49th. We don't have to worry too much about lawyers and liability just yet.



I would like to thank those who lent me their advice. Those that have mega $$$ can go buy a fancy aftermarket system and can pass the liability onto someone else.

 

[GAmes]

Transfer flow used to have a blurb in their literature about gravity feed being illegal. It was taken out of context from federal regs. The actual reg prohibits gravity feed of diesel directly to the injectors. How that would be possible is a mystery to me. I have been using my gravity feed aux tank for over 6 years which includes dozens of trips to Canada and two level one DOT inspections. I have never dumped any fuel overboard. Usually the main tank fills to about 2/3s and the gauge just stays there. If it gets close to full I pull over and close the valve which takes less than 5 seconds.

 

[GaryOwen]

Absolutely correct GAmes. I have had numerous discussions about this reg -FMSCA 393. 65(d). I have personally never used a gravity feed, but I know of many who have with no problems (and a few with problems).

 

[BIGNASTY]

I don't know about Canada but USDOT prohibits gravity flow aux fuel tanks.



Does that mean people don't use them anyway? No.

what Harvey said is for sure in Commiecalif no gravity feed

 

[GaryOwen]

FMCSA 393. 65 (d)



(d) Gravity or syphon feed prohibited. A fuel system must not supply fuel by gravity or syphon feed directly to the carburetor or injector.

 

[steved]

FMCSA 393. 65 (d)



(d) Gravity or syphon feed prohibited. A fuel system must not supply fuel by gravity or syphon feed directly to the carburetor or injector.

That's what I remembered... as long as it feeds into the existing fuel tank, its not an issue.



Being my inspection garage does commercial vehicles, I would have expected a warning or failed inspection for my system. The only thing they ever noted was "you put new hose on your tank?"...

 

[HBarlow]

Gary and Gary, I guess you guys are right.

I don't remember now if I've read the FMCA article and ignored the direct connect issue or simply forgotten.

Oh well, live and learn.

 

[steved]

FWIW, I never shut my tank off, and it never overfills. Now if you were to pop the filler cap open, that's a different story.



I have only overfilled the main tank once, and that was because my dumbself forgot to turn the pump off. I have since quit "pumping" the aux (when it gets low) while driving, and only use the pump to transfer when I'm filling.

 

[HBarlow]

It is nice to never even think about fuel until I've emptied the auxilliary tank. I have about 130 gallons of fuel capacity if I fill both tanks to the neck.

I thought my Transfer Flow 70 gallon tank with automatic transfer was expensive back in late 2001 or early 2002 when I bought it but after many years and hundreds of thousands of miles of service in three Rams it seems like a bargain.

Each time I have moved it to a new truck I have contacted Transfer Flow and purchased a new pump and new mini-computer programmed for the new truck. They aren't expensive.