Solved: Vehicle fuel pump as a transfer pump

Awl --

Thanks to Bob Haller -- and other input, of course -- I found a dert simple way to do this, with no ill effects to the car's pyooter or anything else.

Rather than fool with the pressurized supply line (the shrader valve bob spoke of), I found the *return line* to the gas tank, and used that line. You can distinguish the two by squeezing either with a pliers -- the supply line (to the engine) will shut down the engine in very short order, while the return line back to the tank does not. In fact, squeezing the return line speeds the engine up slightly, which makes sense.

Now, in this scenario (running the engine), you wouldn't want to use the supply line to the engine, bec you could easily starve the engine of fuel in this transfer process, whereas the return line to the tank does not affect the engine one whit. However, if you are careful, you might have better results from the pressurized supply line, being watchful of the engine idle. I opted for the "safer" return line.

So I cut the return line (the short section that is rubber), turned on the engine, and lo and behold, boucou fuel -- on the order of a quart in about

20 secs. For the benefit of the Butt Bros George and JoeBlow, dats 3 qts per min, 3/4 gal/min, or about 45 gals/hr -- not too bad. I hope the Butt Bros were able to follow that.....

Now, the other scenario is, if you are able to jump the fuel pump (which seems to operate off a relay), then you can tap into either line, cuz you don't need to turn the engine on. You may get a higher flow rate by using the supply line with the engine off. And some cars may start the fuel pump just with the ignition on, which would be nice for this.

So after filling a qt, I hose-clamped the tube together with a barbed coupling, until I can put in a T + ball valve. This hose is hose-clamped at either end to metal tubing anyway, no fancy fittings like on the pressureized supply. If I can jump the fuel pump relay, I might fool around with the pressurized side, but the fittings on the end are pretty substantial, so the hose may not be amenable to simple hose-clamping -- altho both the supply and return hoses appear to be the same type of hose.

So this is a really elegant solution to transfering gas, at least from the truck to some other vessel. I'll figger out a way to nicely transfer stored gas to the truck, and it seems like a submersible automotive fuel pump would be a safe way to go, altho manual pumps are certainly viable.

If this works out, I may bump up my li'l doomsday storage depot to mebbe

1,000 gals..... The Butt Bros on Doomsday: Please, Sir, may I have more gas from your return line?????
Reply to
Existential Angst
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Proceed carefully with jumping relays as that is part of the cut off system in the event of an accident.

Reply to
NotMe

all the vehcles I ever owned with pumps in the tank turn the pump on when you turn the ignition key on, after all fuel must be at the engine at start up....

get in your vehicle, turn key, you will hear noise for a moment till the fuel is up. its a normal part of vehicle operation..... once the pressure gets up the pump shuts off........ all automatically.

you could probably buy a fuel pump tester with the schrader valve and cut the pressure gauge off, and use that hose for a fuel line

Reply to
bob haller

all the vehcles I ever owned with pumps in the tank turn the pump on when you turn the ignition key on, after all fuel must be at the engine at start up....

get in your vehicle, turn key, you will hear noise for a moment till the fuel is up. its a normal part of vehicle operation..... once the pressure gets up the pump shuts off........ all automatically.

you could probably buy a fuel pump tester with the schrader valve and cut the pressure gauge off, and use that hose for a fuel line ===================================================

The pump was f'sure not turning on with the ignition, but mebbe that was because the line was already pressurized from earlier startups.

I'll test this by just separating the hoses relieving any pressure, and see if the pump runs on ignition only. I might have to cut the supply side to make this work, tho. But hopefully it will work on the return side as well -- will proly depend on what/where is supplying the back pressure.

Reply to
Existential Angst

I had to drop the huge plastic gas tank on my 89 Dodge van last year to clean the filter sock on the intake of the fuel pump which is electric and feeds the TBI system. I found that there was an extra line capped off that was hooked to a tube going to the bottom of the fuel tank which I guessed was a design feature to allow mechanics to pump all the fuel out of the gas tank before removing the tank. It was easily reached from under the van which led me to believe what I had guessed. The return line is designed to swirl the fuel around the pickup of the fuel pump to prevent debris from collecting in the low spot. It's an interesting design. I figured that drain line would be a good place to install a pump for getting fuel or hooking up an auxiliary tank with a transfer pump like an aircraft has. ^_^

TDD

Reply to
The Daring Dufas

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Dodge REALLY needed to put a access cover in the rear of the vehicles to access the fuel pumps.. Dropping the tank would be unnecessary........

Just as a note DONT RUN YOU GAS TANKS WITH LOW FUEL LEVELS.....

The gasoline also cools the pumps and lots of running with low fuel levels leads to replacing the pump:(

This can easily cost 4 hundred to 5 hundred dollars

Reply to
bob haller

It is not pressure dependent - it is timer - in most cases 3 seconds

Reply to
clare

On my 89 Blazer, I used a sawzall to change the pump from the top.

Low fuel caution is very important. Also, don't buy the high sulfur fuel from Shell, which destroys fuel gage sending units.

Christopher A. Young Learn more about Jesus

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Dodge REALLY needed to put a access cover in the rear of the vehicles to access the fuel pumps.. Dropping the tank would be unnecessary........

Just as a note DONT RUN YOU GAS TANKS WITH LOW FUEL LEVELS.....

The gasoline also cools the pumps and lots of running with low fuel levels leads to replacing the pump:(

This can easily cost 4 hundred to 5 hundred dollars

Reply to
Stormin Mormon

Timer AND engine not turning over. Keeps the pump from barbequeing the occupants if there's an accident and the one or more of the fuel lines is cut. One reason NOT to mess with the fuel pump relay. Also, messing with a safety-related system will probably void your car insurance. Proceed with caution.

Stan

Reply to
Stanley Schaefer

Dodge REALLY needed to put a access cover in the rear of the vehicles to access the fuel pumps.. Dropping the tank would be unnecessary........

Just as a note DONT RUN YOU GAS TANKS WITH LOW FUEL LEVELS.....

The gasoline also cools the pumps and lots of running with low fuel levels leads to replacing the pump:(

This can easily cost 4 hundred to 5 hundred dollars =======================================================

Excellent info!!!! I tend to do that, and would have never thought of this! No more running below E for me.

Here is some info on the Frontier fuel pump:

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I seem to be measuring a higher flow rate than 110 lpm (about 180?), but will have to time this more accurately to be sure. Note the psi, 43 psi -- high enough that I proly won't fool around with the pressurized supply side. The return line is working fine, does not seem to affect the engine at all when filling a container.

Reply to
Existential Angst

How did you come by this info??

Reply to
Existential Angst

I will check that out whenever I can get under the truck. Would be handy if the Frontier has that, another alternative.

Reply to
Existential Angst
********Trim The Fat********

I know a lot of trucks have an option for extra tanks and the factory probably installs a fitting or connection in all of them that would allow a dealer to easily install an auxiliary tank. ^_^

TDD

Reply to
The Daring Dufas

On 1/27/2013 2:43 AM, Existential Angst wrote: ...

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Excepting for it's nonsense folklore--they sit in a well or a can that holds fuel around them...

Reply to
dpb

You cannot buy the fuel that USED to damage SOME fuel guage senders any more. It was an additive thing - not sulphur levels in particular. That's been fixed for about 4 or 5 years.

Reply to
clare

The well helps on those cars that have it - and not nearly all do. It holds fuel around the pump in straight and level driving - but with a low tank, turns, accelleration and decelleration can allow the fuel to slop out of the "can" - and the pump can possibly overheat. It can also "suck air" which does not help the life of the pump any.( and can cause the vehicle to stop and be terribly hard to restart). In MOST cases, fuel flows THROUGH the pump motor, so unless it sucks too much air it is still being cooled.

So on SOME CARS this IS an issue. Not "nonsemse folklore". Running with blocked fuel filters can cause the same kind of problems ON SOME CARS. My recommendation, as a mechanic, is consider anything less than 1/8 tank as time to fill up, and change the fuel filter, if so equipped, according to the maintenance schedule. Some more recent cars do not have a replaceable or serviceable fuel filter - and on "dead end" systems (no recirculating regulator / return line) it is not an issue.

Reply to
clare

Dodge REALLY needed to put a access cover in the rear of the vehicles to access the fuel pumps.. Dropping the tank would be unnecessary........

Just as a note DONT RUN YOU GAS TANKS WITH LOW FUEL LEVELS.....

The gasoline also cools the pumps and lots of running with low fuel levels leads to replacing the pump:(

This can easily cost 4 hundred to 5 hundred dollars ==============================================================

Since I've cut the return fuel line (in the rubberized portion), would it be a good idea to stick in an in-line fuel filter here? I don't see one, am not sure if there is one at the gas tank -- which would be pretty inaccessible. Nissan Frontier, '04, basic 6 cyl.

Reply to
Existential Angst

The fuel filter on my old van is actually underneath attached to the frame on the line coming from the in-tank pump. The pump itself has a fine mesh sock at the pickup end to catch any large debris that may be in the tank. I had to drop my tank and remove the pump assembly because someone who previously worked on it had folded the sock over so that the pump was picking up fuel through a one inch sized circle of screen which easily stopped up with crud causing my van to quit running at odd times. After removing the pump and unfolding the filter sock, I've had no more mystery stalls. My friend LM helped me at his shop where we used his fork lift and it was a such a pain in the tuckus that we never want to go through that again. ^_^

TDD

Reply to
The Daring Dufas

It would act a bit like a bypass oil filter - not terribly effective in this case.

Reply to
clare

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