Using fuel pump & tee in fuel line to fill spare gas can

Greetings TW members! Couldn't for the life of me find this answer on google, or searching this forum, so.....

I have an extended range fuel tank, and want to add a tee into the factory fuel lines in order to use my factory fuel pump to fill a gas can for other, out-of-gas, drivers I encounter. My fuel tank has an easily accessible plug on the bottom that I was considering just threading in a 90-deg elbow, some tubing, and a shut-off valve, but I'm concerned about knocking the elbow out on a rock and draining all my fuel through the hole I just created in the very bottom of my tank. Plan B was to tee into the factory fuel lines, add tubing and said shut-off valve, and simply pull down the tubing, start up the truck, and use the factory pump to fill a gas can for others.

My questions are multiple: Is this a good idea? Which line should I tee into, the pressure line to the engine, or the return line to the tank? Oh yeah, and of the two fuel lines under the truck, which is pressure and which is return (outboard or inboard would be easiest orientation). Another thought entirely would be to tee into the fuel line inside the engine compartment, as if I were running a fuel pressure test, but again, I don't know exactly which line to cut into so I figured I'd ask here first.

Has anyone done something similar to this? Will the fuel pump just keep pumping as long as the key is on, trying (but failing) to build up enough pressure to shut itself off? Does it throw any codes (could easily clear codes with scan gauge if needed)?

 

how often are you running in to people out of gas?

 

Happens often enough on normal highway driving to want to do the mod, as well as wheeling with non-extended-range fuel tank friends. With the anti-roll over valves inside our filler necks / gas tanks, it's basically impossible to siphon from the gas cap side of things.

 

You're an awesome person, my friend.

 

F16, that makes sense. Of course I have no idea which fuel line is pressure side, as they both disappear underneath my supercharger. Attached photo, left is toward front of truck, which is which?

 

you also just put a petcock on the bottom of the tank. no pump. just gravity.

 

Why not just carry a 5 gallon gas can with you in the bed or make a bracket on the bumper to hold it??? That way your not messing with the life support of your truck and possibly having a issue with a fitting or knocking a valve off the bottom of the tank.

If you did Tee it, you could always wire a switch with a relay so when you hit the switch it will power the pump so you don't have to jump the stock relay.

 

Yup, a petcock on the bottom is super easy and reliable, just concerned about those wayward rocks. I tend to, uh, bash things up a bit under there and I would probably find a way to get a rock in the perfect spot to break off that petcock valve and drain my tank entirely.

Carrying a 5gallon can defeats the purpose of spending thousands on my extended range fuel tank. I have a double cab short bed, and at 5ft long, that short bed gets really short really quick when I load it up for a week out in the dirt. Not much room left for fuel, and not into carrying fuel on the rear bash bumper either.

Definite yes on wiring the separate switch for the fuel pump, that part I can figure out easily enough. Just clueless on the fuel lines. Where's all our forum Master Mechanics when I need one?

 

You are dealing with high pressure what ever you do will require some thing better than rubber hose and clamps. The pump will not run with out the engine running or a wiring by pass. The pressure side is at the fuel rail the return is at the regulator. Frankly I think it is a bad ideal but it's your truck if it springs a leak the truck will stop and there will be gasoline every where.

 

I installed an URD fuel filter at the quick disconnect in front of the tank. One side is rubber hose with plumbers tape, the other side the fuel filter just plugs into. It's not a bad idea to upgrade to a better fuel pump, get an external fuel filter, AND have an easy way to plumb in your tee-

http://urdusa.com/Fuel-Upgrades-Fue...uel-Pump/Filter-Upgrade-Kit/product_info.html

 

The running fuel pressure to the engine is more like 35 PSI once your dump valve is closed any where in pressure side of the line. If you dead head the pump the pressure will climb to over 80 PSI. If you just remove the supply line yes the pressure is quite low but if it is "T"ed in to the system as soon as you close the valve it is now at 35 PSI on every part that is connected. Common rubber hose is not designed to with stand that kind of pressure and if you use clamps a full circle clamp should be used. I all ready said if you want the pump to run it will have to be jumpered. It's your truck do as you wish I think it's foolish and dangerous.

 

Yes that would work. However a added "T" once it was closed and he was driving down the road it will be at line pressure. Most of the fuel the pump delivers is returns to the tank it is regulated to some where around 35 psi the pump is capable of closer to 80 psi excess pressure is returned to the tank that is what the line pressure is on every part of the fuel delivery system including any thing that is added on. If you just remove the fitting at the fuel rail and aim it into a bucket then the pressure would be what ever the resistance of the fuel system is and that would be very little but that would be far more effort than it's worth. If you "t" a line on the return side with a two way valve to dump the fuel out instead of back into the tank the pressure would be no problem unless you forgot to turn the valve back on. A simple valve could not be used because if the return is blocked the line pressure would become pump pressure and if nothing blew up the truck probably would not run any way.

 

All very good information, thanks to all! I feel that adding a tee to the line returning fuel to the tank is fairly safe, since the tank is an open port on that end (fuel line just dumps fuel openly onto the fuel pump for cooling, never a closed line to build up pressure in). I would be siphoning fuel that the engine otherwise does not need, idling or not, or just key on, or fuel pump relay jumped, etc.

And the URD external fuel pump / filter looks like a winner. I've been bummed about the internal OEM fuel filter for years, having been stranded in the desert in SoCal when my first extended range fuel tank rusted out on the inside after less than a year of use, clogging the OEM filter and leaving me driving home to NorCal in a rental car for a week. Easy to run an extra wire & switch for this fill a gas can idea of mine as well. Thanks again for all the input!

 

Spare gas can. Why set yourself up for a breakdown? Or worse, a fire?