2nd Gen Non-Engine/Transmission Auxilary Fuel Tank Setup

[Nate]

I have this posted in another thread, but it's not getting many responses.



I'm trying to figure out how to tie into the stock system. Mainly I was thinking of the gravity feed method, since it's simple and cheap.



Now can I do something like the guy on DTR did?

http://www.dieseltruckresource.com/faq/faq.php?display=faq&nr=167&catnr=10&prog=1&lang=en





Now if stock tank won't leak with another 50 gallons pushing into it, that's fine. I'm guessing these is no vent in the tank?



Now where will the returned fuel from the injection pump go? It will have to force itself into the stock tank? Should I re-route the line to the aux tank?

 

[rrausch]

5 years ago I got a 45 Gal, in-the-bed, alum. treadplate tank from Aero Tank. I love it. But the way I plumbed it was like this: I ran two lines into the stock-tank filler neck. I used 3/8 steel brakeline and drilled holes into the filler-neck and had the lines welded in. Then I connected one line to the top-side of the Aux. tank as a vent line, so the tank wouldn't suck in outside air as it was drained. The other line I connected as a supply line to the bottom-side of the Aux. tank. In that line I installed a big NAPA diesel filter, a 12V pump, and 12V solenoid-driven on-off valve. I put a good toggle-switch and a green LED light on the side of my aux. gauges, and wired the switch so that it wouldn't work if the key was off. I have saved a lot of money on diesel by buying that extra 45 gal. when prices were low.

 

[Joe G.]

My tank is different than that. I made it so it is easy to take out if I want to haul something that is loose like crushed rock or requires the entire bed. Most of the time it is in the bed, but I do have the option to remove it if I need to. I used fuel hose from the connector in the side of the bed to the aux input fitting on top of the fuel module. That is what it is for. No modifications needed to the stock tank. I used fuel hose from the aux tank fitting to the pump and on to where the hose connects to the fitting in the side of the bed. I originally had a solenoid shut off valve, but some experiments showed me that it was not needed. My tank was originally on a dump truck. It holds 50 gallons. It has a fuel level sending unit from the dump truck. I bought a fuel level gage from Westach that works with that sending unit. I use a trailer plug for the electrical connections. The type with a metal cover that is spring loaded. That protects the wiring connectors if I have the aux tank out and a load of something like rock. This part is all pretty simple. The next part is not so simple.



After a few episodes of forgetting about the pump being on (in spite of the LED) and oiling down some tailgators I designed and built an automatic pump controller for the pump. When the main tank gets low the pump comes on. When it is full the pump turns off. If the aux tank runs out of fuel the pump controller turns the pump off. That works well in spite of my bad case of CRS.



I have modified the stock tank so the humps are vented to the filler neck vent. That allows more fuel in the tank (about four gallons I think, maybe a bit more) and reduces foaming when filling it.

 

[GAmes]

Now if stock tank won't leak with another 50 gallons pushing into it, that's fine. I'm guessing these is no vent in the tank?

Yours may be different, but my 97 has a fuel tank vent and it will leak if I forget to turn off the ball valve and the main tank fills to the top.

 

[scotmartin]

This is what I used to have.



https://www.turbodieselregister.com/user_gallery/displayalbum.php?&userid=15271&albumid=1302

 

[Nate]

I wasn't sure. I was just referring to the DTR thread where he just made both tanks one so to speak.

 

[GAmes]

I wasn't sure. I was just referring to the DTR thread where he just made both tanks one so to speak.

He shows a ball valve, the gizmo with the bent yellow handle.

 

[Nate]

Right. The way he made is sound is that it was left open with a full tank of fuel in the aux tank and main tank.

 

[ichoplin]

Here's how I've tied into the stock system on four personal trucks and three friends' trucks.

Simply build a "t" with one leg being 3/8"(or whatever size you need) and the other two legs 3/4"(or was it 5/8"?) and splice in the filler neck vent tube.

I don't gravity feed mine, but I know others that do. I have NEVER had an issue with over pressurizing or anything like that. The only thing I've had to deal with is fuel being siphnoed through my 12volt pump. A shut off valve cured that.

Very easy and cheap.

Ian

 

[Cummins Pilot]

Seems like a lot of us have set our up the same way give or take a part. I'm going to get an electric fuel cutoff solenoid so the siphoning stops and I can get rid of the ball valve. I hate getting out of the truck.



Heres my problem and I've been wondering if anyone else has this problem. I wait until I'm down to DTE = 0. I flip on the transfer pump and I can watch the gage rise to about 1/4 and the dummy light goes off. It stops rising from there. At 7mins 43 secs from DTE=0 I turn off the pump (found this out the hard way). I have to shut off the truck and restart so the gage resets to the correct level in the tank. Wish the gage worked right because I always get a bad case of CRS when transfering fuel. Need a kitchen timer taped to the dash.

 

[Joe G.]

I guess the later trucks have an improved fuel gauge system. My '95 gauge shows the rise in fuel level. My CRS problem is that I forget to look at it so when I see the tailgators back off with their wipers going I know that the tank ran over. If my pump is off there is no siphoning. I experimented with that because somehow the solenoid valve was interferring with the fuel level gauge for my bed tank. I removed it and it does not siphon when the pump is off.



I think that the voltage on the wire from the tank sending unit is following the fuel level. It's a little less than 4 volts at empty and close to 0 at full. You could rig a voltmeter on the gauge wire and shut the pump off at 1 volt.

 

[Nate]

See I just want to make both tanks into one more or less. 34 gallons in the stock tank and another 40 or so gallons in the tank in the bed. When the guage starts coming off full, I'll know that the aux tank is empty.



Now I was thinking if I would block the vent off at the main tank, run the return line into the aux tank and then plumb the aux tank into the filler of the main tank, in theory it shouldn't leak.



I don't know if that makes any sense?

 

[wtfd6]

the reason the gauge stops going up is the buffer in the system. it is there so that if your fuel is down, the gauge doesnt fluctuate with the sloshing of fuel in the tank.


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