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How to empty a fuel tank in a 1994 F150?

O'Rattlecan

Redneck Prognosticator
26,687
797
Belton, MO
So the question is in the subject line.

How do I empty the fuel tank in the 1994 F150? I have not yet reattached the fuel lines to the truck. Can I get a large bucket and just aim the ends of those lines into a bucket? If I leave the key in the 'run' position, will the fuel pump continue to run, or will it have a safety feature to shut it off?

Would it be easier to simply use a siphon?

Advice would be appreciated in the technical aspects of how the pump works.

Ryan
 

Ridgerunner

Missouri Chapter member
23,457
573
Stillwater Ok
So the question is in the subject line.

How do I empty the fuel tank in the 1994 F150? I have not yet reattached the fuel lines to the truck. Can I get a large bucket and just aim the ends of those lines into a bucket? If I leave the key in the 'run' position, will the fuel pump continue to run, or will it have a safety feature to shut it off?

Would it be easier to simply use a siphon?

Advice would be appreciated in the technical aspects of how the pump works.

Ryan

I always use a siphon then when it is empty drop the tank to get the rest by removing the sending unit. You should be able to get a new gasket and locking ring, also a new float at the service dept.

I also go to a mom and pop tire store to get a couple of inner tubes from a truck like a 18 wheeler cut them to fit the straps od the gas tank along with the top of the tank for extra protection.
 
If the 94 is like my 87 there will be a low pressure pump in each tank pumping up to a fuel tank selector/collector (operated by fuel pressure from the in tank pumps) and then trough to a frame mounted high pressure pump which runs the fuel rails - when I emptied mine I disconnected the lines from the fuel collector/tank selector and pumped into 20L jerry cans by leaving the key ion the run position.
Siphoning works well provided you can get someone else to do the priming suction for you :) :)
 

Fellro

Moderator
Staff member
If everything is working properly, the pumps shouldn't be running constant in the run position... You can use a jumper at the relay though to power them . Simply unplug the relay and hook up a jumper in the place of the relay. I can't immediately say which are the power wires, but one is full time live, one is the power out to the pump supplied when the relay is on, but one is a ground for the relay, and the final is th e power to trip the relay. The wing for the relay often is on the top or side of the relay telling you how the power is routed through it.
 
I've never had to empty a tank with a pump inside it, but could there be a way
to put low air pressure into the tank to force the gas out ?
There's just something about electricity inside a tank of gas fumes the scares me.'hiding_smilie' 'hiding_smilie'
 

Fellro

Moderator
Staff member
The pump would be enough restriction to not work that way. The pumps are sealed, so I don't worry about that too much. Since they are factory, and the liability goes back to them even after these years, or at least the pump manufacturer, so I don't worry about trouble that way too much. I just let the pump do the work for me...
 

O'Rattlecan

Redneck Prognosticator
26,687
797
Belton, MO
are we talking about a $10-20 item or something that costs more? At this point of the build I just want to FINISH. Extra work doesn't sound appealing at this time, and time saving things sound great.

Ryan
 

LEB Ben

Arrogant A-hole At-Large
34,919
1,124
outside your house
Siphon...I've used regular old garden hose or fuel hose down in to Thunders tanks before...take a few deep breaths on the other end...drop the hose in to a 5-10 gallon bucket...and enjoy the buzz.

OR....

I've seen some mechanics at shops take a cheap generic electric fuel pump and hook it to the siphon hose.

This. I have a couple cheapy Mr. Gasket electric fuel pumps mounted on the inner fenders of my rigs I use for tasks like this. Surprisingly useful.
 

LEB Ben

Arrogant A-hole At-Large
34,919
1,124
outside your house
If your going to siphon , don't suck, put a rag around the fill and blow into the hose.
The pressure will then force the gas up the hose and start the siphon.

But then you don't get a buzz...
 

Fellro

Moderator
Staff member
I'm not pulling the bed, screw that. I'll just use as siphon.

Ryan

????
If the factory pump is still good, I see no reason to pull the bed. Let the pump do the work. I wouldn't get too concerned anout the little bit remaing. Fresh fuel and some Sea Foam and you will be fine.
 

O'Rattlecan

Redneck Prognosticator
26,687
797
Belton, MO
Aren't the pumps accessible from the top of the tanks? So I either have to drop the tank or pull the bed, right? I was just being a grouch coming back the way I did - sorry about that.

Ryan
 

Beach66Bum

Moderator
Top Poster Of Month
Aren't the pumps accessible from the top of the tanks? So I either have to drop the tank or pull the bed, right? I was just being a grouch coming back the way I did - sorry about that.

Ryan

that's correct Ryan.

I have seen a truck bed where the owner cut an access hole out from the bed to get at the pump :rotz:
 

Fellro

Moderator
Staff member
I have pulled the pump out of the front tank numerous times without dropping the tank or raising the bed. Back tank, not so much. It is easier when the exhaust isn't in the way, you can go across the drive shaft. It makes it easier when I know what has to happen though.
 

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