Using fuel pump to empty tank

[turboshad]

With the higher price of race gas this year I don't think I will be driving around on the left overs like I did last year. I also want to be as sure of the concentration in the tank as possible. I do plan on making a dual tank setup but in the mean time does anyone see any issue with me jumping the fuel pump and running the feed line to a jerry can to empty the tank? Would running for extended periods of time with no back pressure harm it or is it easier than running with pressure? I would think the latter but was curious what others thought. Thanks.

[86Shelby]

I've done it several times. It only takes a few minutes to empty a full tank.

[135sohc]

The chrysler fsm direction for emptying the gas tank involves unhooking the fuel line in the engine bay and using an extension line "to an approved container" of course while using the DRB to run the fuel pump.

I dont see anything wrong with your method.

[bakes]

No it won't hurt any thing. I like to use the fuel test port to drain the tank.

[cordes]

That is the best way to do it.

[4 l-bodies]

DJ,
I've been draining the fuel tanks in all my GLH's like that for 20+ years with no ill effects. Load em up with fuel for the long hibernation season and then transfer that fuel into my everyday drivers in the Spring.
Todd

[turbovanman²]

That's what I used to do, :thumb:

[GLHS60]

I do it all the time unless the pump is shot then use the siphon port.

Thanks
Randy

[turboshad]

There's a siphon port?

Thanks guys. I was pretty sure it would be fine but didn't want to take the ignorant path of burning my pump up. :thumb:

[Turbo3Iroc]

How are you guys jumping the fuel pump? I've always let the car idle and used the return line.

[bakes]

I cheat i use a scan tool

[Turbo3Iroc]

I have heard of the DRB being able to do this but I have a OTC 4000E and don't know of anyway to power the pump.

[OnLooker]

I have emptied a tank by using the pump. On my 87 GLHS I just unplugged the fuel injection harness and the pump will stay running.

[Chris W]

+ side of battery to coil will activate the fuel pump.

Chris-TU

[cordes]

+ side of battery to coil will activate the fuel pump.

Chris-TU

That is how I do it.

[Turbo3Iroc]

+ side of battery to coil will activate the fuel pump.

Chris-TU

Does it work on a TIII car?

[BadAssPerformance]

+ side of battery to coil will activate the fuel pump.

Chris-TU

Good to know.

I usually disconnect the injector harness and cycle the ignition key to "run" and it latches the fuel pump to stay on. ... works on LM and SMEC cars, not sure on SBEC or newer.

[cordes]

Does it work on a TIII car?

Do the TIII cars give power to the coil via the Z1(?) circuit that the fuel pump is on? If so it should still work.



Good to know.

I usually disconnect the injector harness and cycle the ignition key to "run" and it latches the fuel pump to stay on. ... works on LM and SMEC cars, not sure on SBEC or newer.

I did not know that. Thanks for that tip.

[4 l-bodies]

How are you guys jumping the fuel pump? I've always let the car idle and used the return line.
I cut a couple different style fuel pump electrical connectors off of some cars in the salvage yard. Tied them all together & and have about 15 feet of wiring with some alligator clips. Unplug fuel pump connector, plug in my electrical connector, attach to battery. My home made tool will drain any of my TD's. IMO, takes to long to let the car idle to drain the tank.
Todd

[prepared]

jumper wire with alligator clips. One end to battery + and one end to coil +.

Prior to this, I unhook the rubber return line at the regulator and hook a long hose up to the regulator and over to a gas can.... or if I'm draining OLD gas, from the regulator to my truck. :D

[raccoon]

There's a siphon port?

yup white vent looking like thing at the top rear of the tank.

[turboshad]

Ok, so I made a hose with a -6/hose barb fitting and then undid the line at the filter on my fender and pumped it into a can. While it was pumping the fuel would come in waves in a pulsing fashion. Is this normal? I expected it to be a steady flow but maybe I was wrong.

[turboshad]

Well after tuning and finding out I was short on fuel I decided to put in the 1200cc injectors. To make sure they didn't leak I figured I would crank up the fuel pressure and low and behold the darn pump wouldn't go past 60 psi and it eventually popped the fuse. I've been meaning to rewire the thing for a while and I guess I should have sooner than later. Wired it up with some 8Ga and it was like a new pump. Probably why I was running out of injector too. I'll see when I pump out the race fuel if it still surges or if that was the problem.

[4 l-bodies]

Ok, so I made a hose with a -6/hose barb fitting and then undid the line at the filter on my fender and pumped it into a can. While it was pumping the fuel would come in waves in a pulsing fashion. Is this normal? I expected it to be a steady flow but maybe I was wrong.
DJ,
Since I have been doing this for 20+ years this same exact way, I can tell you you are probably sucking air if you are getting a pulsing or foaming fuel. Mine always comes out clear and steady until I get very low on fuel. So to answer your question, no it's not normal. Your logic is sound, your fuel system is not.:p
I discovered I had a pump that was sucking in some air by noticing it would be foamy after it got below 1/2 tank. Dropped the tank and sure enough found the problem. Another possibility is if you have an electrical issue or had a battery that wasn't real strong. You can always put a charger on the battery and repeat the test if you suspect a electrical issue.
Good luck,
Todd

[86Shelby]

How are you guys jumping the fuel pump? I've always let the car idle and used the return line.

I have sat and let the car idle with the return line disconnected, but it takes quite a long time. On the R/T I simply turned the ignition on and jumped the ASD relay with a spare piece of wire.

I really like Todd's idea of having a long jumper harness. That sounds like it would be the hot ticket on an Lbody where the pump is easily accessible.

[Turbo3Iroc]

I have sat and let the car idle with the return line disconnected, but it takes quite a long time. On the R/T I simply turned the ignition on and jumped the ASD relay with a spare piece of wire.

I really like Todd's idea of having a long jumper harness. That sounds like it would be the hot ticket on an Lbody where the pump is easily accessible.

When I have had to drian fuel it hasn't ever been more than a few gallons. For a whole tank I would have been looking into something like this. Nice to know, I may try it for grins pretty soon since it it a lot more difficult on my car to get the return line off with the AN stuff. Just a placement thing.

[turboshad]

With my concern of the pulsing fuel when emptying the tank I pulled the pump today to take a look. I found that the pump will suck air if the canister doesn't have enough fuel in it. So when I disconnect the return line the canister doesn't stay full of fuel when the level gets lower. It does sort of "drain" fuel from the tank into the cansiter but it will only ever be as high as the tank level and the pump doesn't pull fuel through the in-tank filter off the bottom like the older ones do. I don't know how excited I am about that and it makes me want to upgrage the fuel system even more. I don't think it is an issue when the return is hooked up but the more fuel you use at the engine the less will return to keep the canister full. I couldn't see a good work around for the design. Any thoughts on it or has anyone found it to be a problem in higher HP builds?