Diesel Place banner

1 - 20 of 21 Posts

·
Registered
Joined
·
279 Posts
Discussion Starter #1 (Edited)
Is it possible for a 2016 LGH van ECM to control dual tanks? The cab and chassis have dual tanks, but they have different OS. I have EFI Live. I got a second 30 gal tank, and while I could put switches in cab to control the fuel transfer, my ideal goal is to make this process fully automatic.

I do not want to do the gravity/sump.
 

Attachments

·
Registered
Joined
·
897 Posts
So the rear tank pumps into the front tank? I'd probably just hook it up to a switch. I mean, it's not something you'll need to do all the time. Getting low on fuel.... Then hit the switch.
 

·
Registered
Joined
·
279 Posts
Discussion Starter #4
Yes the rear tank has just a generic fuel pump that transfers to the front tank.
I have had the 2 switch set up on my 2006 8.1 van. One switch would flip the fuel gauge, second switch ran the fuel pump and had a red LED indicator.
The problem with the switch is that it takes 15-20 minutes to transfer. So on long drives you simply forget to turn it off. The pump will be running dry which may shorten its life / burn out. In order to solve this, I could solve that with this little Timer device, that will run the pump in 10 minute intervals, I'll just have to push the button several times.

I was so happy when I discovered the so-called "Fuel tank balance module" that came in late GMT-400 C3500HD trucks. It is mounted on the frame, so I don't need to run miles of wires and it can all stay with the tank. It's brilliant. It doesn't require a data connection or calibration etc. It only has 6 wires: ground, 12V, 2 fuel tank levels for input, and outputs one combined fuel level to the IPC and fuel pump relay signal. It does all the math.

There is one problem with it that I cannot solve. Our senders are 250 Ohm full, 40 Ohm empty. GMT-400 trucks were 40 Ohm full, 250 Ohm empty. GM flipped this for 2004+. So that module expects opposite input signals and outputs it the opposite way, too. I did not find an elegant solution yet.
 

Attachments

·
Registered
Joined
·
825 Posts
There is one problem with it that I cannot solve. Our senders are 250 Ohm full, 40 Ohm empty. GMT-400 trucks were 40 Ohm full, 250 Ohm empty. GM flipped this for 2004+. So that module expects opposite input signals and outputs it the opposite way, too. I did not find an elegant solution yet.
they used to sell just the potentiometers...not sure if they do anymore
just looked it up on rock auto...you can get a silverado "fuel level sending kit" for $30 or so, just use the van swing arm and float..
 

·
Registered
Joined
·
279 Posts
Discussion Starter #7
just looked it up on rock auto...you can get a silverado "fuel level sending kit" for $30 or so, just use the van swing arm and float..
This, or flipping the arm 90 degrees so it works opposite. I could do, but the module will still output the reversed signal to the cluster.
 

·
Registered
Joined
·
825 Posts
Yes the rear tank has just a generic fuel pump that transfers to the front tank.
I have had the 2 switch set up on my 2006 8.1 van. One switch would flip the fuel gauge, second switch ran the fuel pump and had a red LED indicator.
The problem with the switch is that it takes 15-20 minutes to transfer. So on long drives you simply forget to turn it off. The pump will be running dry which may shorten its life / burn out. In order to solve this, I could solve that with this little Timer device, that will run the pump in 10 minute intervals, I'll just have to push the button several times.
Just add a 2psi pressure switch override to a short timer, when you arm the circuit the timer turns on the pump (for 20secs or so) this would be plenty of time to build pressure, from that point on as long as there is pressure the pump remains on, as soon as pressure drops the circuit is disarmed (until you reset power to the timer).
 

·
Registered
Joined
·
3,485 Posts
Is the wiring pigtails already there on the van to where you can plug it in to do a test ?
 

·
Registered
Joined
·
279 Posts
Discussion Starter #13
One problem with this approach is that both tanks are roughly the same size, so unless I turn the pump on with main tank almost empty, it could overfill the main tank. And you don't want to starvate the engine of fuel either. Although I do not think anyone else besides me will be driving the rig, I want to eliminate the human factor completely. The beauty of the balance module is that it transfers 3-5 gallons at a time requiring no human input.
 

·
Registered
Joined
·
3,485 Posts
Pigtails for what? Not sure I understand.

LCAC_Man, I like this psi idea. Similar to fuel pump relay bypass done with the oil pressure switch in the 1990s cars.
Does the van you want to put this on already have the factory wiring in place ?
 

·
Registered
Joined
·
80 Posts
Is it possible for a 2016 LGH van ECM to control dual tanks? The cab and chassis have dual tanks, but they have different OS. I have EFI Live. I got a second 30 gal tank, and while I could put switches in cab to control the fuel transfer, my ideal goal is to make this process fully automatic.

I do not want to do the gravity/sump.
Standard wheelbase or extended?

I'm looking at the distance from the main tank back to the axle.

I'm also curious about using the Cutaway chassis 55 gallon tank behind the axle.
 

·
Registered
Joined
·
80 Posts
Thanks! You mentioned that the 55 gal won't clear in the other thread, as well as Ford tank that will. What's the relationship of the Ford tank to the one you show here?
 

·
Registered
Joined
·
279 Posts
Discussion Starter #20
Two pics show the roughly 30 gal tank I sourced from some Econoline van that had wheelchair conversion on it. It is just metal and does not have any part #s or identification. I mounted a GM fuel sender inside of it it will show 40-250 Ohms (match the main tank) and put a new $8 generic fuel pump in it. Has GM quick disconnect fuel fittings and it drops down if I ever have to service it.
Tank occupies pretty much all available space, with 1/4" clearance to 2nd last body mount bracket, 1" to trailer hitch and 1" to exhaust pipe. Anything bigger than that would require a custom shape to work around exhaust and body mount brackets.
 
1 - 20 of 21 Posts
Top