Modifying a vehicle for E-Z fuel transfer

Decided to add quick-disconnect fuel fittings to my small pickup this weekend, in order to provide an easy method of transferring fuel to a gas can. Basically, the idea is to use the engine's fuel pump to transfer the fuel.

These fuel fittings are for "Suzuki/Honda" outboard motor applications. The smaller, male fitting doesn't come with a hose barb on it, so a brass 1/4" hose barb to female 1/4" NPT adapter was attached:


The hose for filling a gas can uses ordinary 1/4" ID vinyl tubing:



Like most modern vehicles, this one has a fuel return line that sends excess fuel back to the fuel tank - and that's where the fittings are added.

On this particular vehicle, the return line comes out of pressure regulator that is built into the mechanical fuel pump - On many vehicles, it comes out of a separate fuel pressure regulator instead. The fittings are installed in the fuel return line as it exits the fuel pump. Unplug the return line (right) to connect the transfer hose (left) to the fuel pump; re-connect the return line when finished:


All hooked up for transferring fuel:


RESULTS: This scheme moves fuel faster than by gravity siphon alone, but is still hindered by the small size of the fuel lines. I would estimate that it'll transfer around 1 gallon every 7 or 8 minutes, running the engine at a fast idle - adequate for putting a few gallons in a small gas can, but NOT acceptable for refueling another vehicle! Presumably, bigger fuel lines on a larger vehicle would transfer the fuel faster.

Biggest advantage is that it's VERY handy - takes just a few seconds to hook up or disconnect.

I like the quick connectors, taking a mental note now.

I think it would make more sense to add a quick connect on the supply side and buy an electric pump and use that for transfers. Your battery is right there, it could be mounted in that space on the fender and you don't have to run your vehicle to transfer fuel.

I was going to suggest that to, an added benefit is you don't risk dealing with fuel dripping on a hot engine, but I figured he did it this way for whatever reason he chose.

Another good reason to just do an electric portable pump is it will work even if the truck doesn't start.

Simplicity is the main reason for not adding an electric fuel pump - just 3 quick-disconnects to buy. It also avoids any sparks created by turning an electric fuel pump on or off.

This approach works with just about any vehicle. Most vehicles built within the last 15 years or so have an electric fuel pump inside the gas tank itself. Connecting an external fuel pump to these vehicles doesn't work, because the new fuel pump won't draw gas through the existing pump unless it's also running - which kind of defeats the whole point of adding another fuel pump anyway.

Also, most vehicles have a "crash protection" feature that automatically shuts off the electric fuel pump if the engine isn't running - so you can't just leave the ignition switch on and expect the electric fuel pump to run for more than a few seconds.

So - you either have to (A.) rig up a wiring arrangement that temporarily bypasses the vehicle's existing connections to the fuel pump, or (B.) run the engine while you're transferring fuel. I chose option B.

Very neat. What kind of vehicle is that??

1988 Dodge Ram 50

I wa wanting to mount on all of my vehicles something similiar, But without the add of the cars fuel pump.
I was wanting to put a T fitting inline near the tank and just pump it out of the tank with an external fuel pump.
My only concern is will the new quick disconnect external fuel pump draw through the cars fuel pump mounted in the gas tank if the ignition switch is off?

Nice setup by the way!

Nice job, Ski.
I saw some of these fittings yesterday at Gander Mountain in the outboard motor section.

Most in-the-tank fuel pumps use an electric motor to spin a small pair of gears, or a "georotor". Neither of these arrangements allows fuel to be drawn through the pump unless it's spinning - they are both very restrictive to fuel flow when the motor isn't powered up.



You might be tempted to draw fuel through the return line instead, since it isn't connected to the fuel pump - but it doesn't extend deep enough into the tank to draw in fuel.



So, unless you want to punch another hole the fuel tank to attach your own fittings, or stick a siphon hose down the filler neck, the only way to get gas out of a vehicle with an in-the-tank fuel pump seems to be to use that pump to transfer the fuel.

All good info here. Just make sure the QDs don't leak or become disconnected. I've used the regulator overflow line to completely drain a tank in preparation for tank removal (fuel pump swap, that anti-return valve likes to leak).

Also, on diesel engines, be very careful in trying this. Since there are a many different systems out there, you can run into problems. Older GM 6.2s are pretty easy as they have a return line. And some use return flow through the filter to keep fuel temperature up in cold weather.

Most vehicles use a flapper valve in the filler neck of the tank to prevent sloshing into the vapor recovery system so the charcoal can won't get a slug of liquid. This will inhibit siphoning.

I may do that to mine also

Interesting.

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