moparguy

I've installed a home built aux tank that uses a 12v pump to transfer fuel. Now I'm trying to figure out how to tell when I've transfered all the fuel to the main tank. My concern is I'll burn up the pump if left running to long after the tank is empty (or forget to turn it off).

I'm thinking a oil pressure sending unit could be made to work if T'ed into the fuel line, it would cause a light to come on (or go off) when the tank is empty and fuel pressure drops between the main and aux tank.

Any thought on this idea, which sending unit to purchase, wiring tips ect..

Thanks, RJR

Moose10

How about an aftermarket fuel level gauge......probably fairly cheap.

infidel

Problem with a pressure switch is there probably isn't much pressure to begin with since you're pumping downhill. My bet is less then 5 psi.
How about one of these http://www.jcwhitney.com/autoparts/P...p-1057/c-10101

moparguy

Don't know if you remember Bill, but this is the saddle tank I built 3 or 4 years ago. It mounts between the frame rail and outside skin of the bed on the passanger side in front of the duals. Can't see it unless you look under the truck. I'm pumping fuel out of the bottom of the tank, then uphill about 20" then about 2' or 3' across to the main tank.

I had considered a sending unit, but would much rather use some type low pressure sensor, or flow sensor to trigger a small idiot light. I could install the light in the pillar pod and not clutter up the dash with another guage.

Thanks RJR

infidel

RJ, I'll bet the pressure is still lower than an automotive type sender will work on. Most oil pressure senders are set to turn on the idiot light at 10 psi. What I'd suggest you do is install a compression tee in the fuel line where you want the sender with a gauge and see what kind of pressure you're looking at. I buy high quality pressure switches to protect my ag booster irrigation pumps from running dry from these guys. Third one down is what would probably work for you. These folks are great to work with and their prices aren't bad at all.
http://www.pressureswitches.com/swit...6.html#series1

Hemi Cat

Maybe a fuel sending unit with a low fuel sensor built in. I think my old 89 Dakota had one like that. You could use that signal to turn a relay on or off to run your pump. Or possibly put a micro switch on the sender arm.

moparguy

That's what I'm looking for Bill, you're right about the pressure, it's gonna be low, I'm feeding the main tank though the little unused 1/4" plastic nipple on the fuel tank module. It was a closed nipple but a pair of side cutters fixed than and it's now my fill point. It's id is smaller than the 3/8th supply hose which will provided a bit of restriction and allow pressure to build a bit, but not much.

Thanks, Ronnie