I have an 80gal aux tank that I hooked up from the drain valve to the neck of the main tank (with deezee kit). 50 minutes ago I filled the aux tank with 20 gallons of diesel and the fuel guage read just above 1/4 tank. Now, it's still about where it was (maybe a 32nd or 64th fuller). I'm wondering if I start off with a full main tank and full aux tank on a trip if it will keep the main tank full (keep up with the usage of fuel). I opened the filler cap on the main tank and can hear it trickling in but the rate is what bothers me.

When I ran the line I didn't go straight down under the bed because there was a hole already just 12 inches away so my fuel line is routed horizontal to that hole then down then horizontal under the bed and to the nipple on the tank. Hopefully you all won't say it has to go on an incline down to the tank because that is hard. Tank is towards the cab on the passenger side and fuel neck at the back drivers side.

 

What size is the drain hole/hose from aux tank?

 

I'll have to find the plug and measure it tomorrow but this is the fuel line I'm using.

 

I just found out that Autozone has a universal fuel pump. I'm going to try hooking that up today and see if it work better than gravity fed.

 

do you need to fill the main tank first then fill the aux on a gravity system? If the main is half full and you fill the aux how does the air escape from the main to let fuel in?

 

This is one of the main reasons why I purchased an ATTA 45RBR with the fuel pump system. I wanted positive control over the fuel flow, and I have that with a large momentary switch I installed in the center console.

This was one of the best modifcations/upgrades I did for my truck. Loaded with the 5 wheel I get ~900 miles in range and without I get ~1400 miles in range. Stopping when I want instead of when I have to is great. Also, I get a kick out of watching the fuel gauge go up as I am rolling down the interstate at 65 MPH.

I am 99% sure this is the fuel pump that came with the kit. Another plus as I can get this or something similar to it anywhere.

https://www.oreillyauto.com/detail/p...e16371/4615545

 

Hypothetically speaking, IF one would put a hole at bottom of main tak, that's plumbed to bottom of aux tank, with no solenoid, bank valve..etc, would it gravity feed always, filing the main tank but NOT over filling it?

 

I get the same flow rate with the cap off or on to the main fuel tank (as well as cap off of the tank).

 

The kit I got that you cut into the filler tube has a ball valve on it. If fuel comes up in the neck it pushes the ball closing the aux tank. I guess if a person left the pump on it would have an overflow situation but I plan on doing what Sous does and turn it off when it gets nearly full. I'll definitely have to keep track of the gallons.

 

Now you have me thinking! Cylindrical tank 24"x36" under my flatbed in front of the drivers rear wheels. Switch and a pump to pump into the oem tank hmmmm.....

 

Not sure if you caught it, but I use a spring loaded momentary switch. As I am driving down the interstate or straight country road I lift the lid on the center console and push and hold the switch down. After a couple of minutes, I take my hand off the switch and close the center console cover. I just filled my tank about 1/4 of the way.

This switch setup is good so that you don't forget that it is on and overflow the main tank. Also, it gives you 100% control over the flow of fuel into your main tank.