FAST EFI FUEL PUMP WITH 2 TANKS---HELP!!!
 

Ok guys, I need your help with my EFI fuel pump setup. Here's what I'm working with...

I have a 78 Ford F150 that I'm putting a 460 in. I wanted to convert it to fuel injection so I purchased the FAST EZ EFI throttle body fuel injection setup. I purchased the master kit, which included the EFI fuel pump. The problem is the system is set up for 1 gas tank and my truck has 2 gas tanks. The instructions state that the fuel pump needs to be mounted as close to the gas tank as possible, no more than 20" away. This means that my rear tank will be too far away for my fuel pump to operate without damaging or burning it up.

So my solution is this (and this is where I need your help and advice, so if I'm wrong, please correct me)...I need to install a separate (secondary) fuel pump and mount it back by the rear tank to pump fuel up to the FAST fuel pump. I will mount the FAST fuel pump in front of the "Y" junction that switches to the different tanks. If I do this then I don't want the rear secondary pump running while I'm not using that tank. So my solution to this is to wire the secondary pump to turn on when I switch the toggle switch on the dash from the main tank to the Auxiliary (rear) tank. Am in on the right track here? Will this work?

Another question regarding the PSI on the secondary fuel pump....what psi fuel pump do I run since this pumps ONLY job is to pump fuel from the rear pump up to the FAST EFI fuel pump, which will then take over duties of supplying the throttle body???? The FAST Fuel pump is to be set at 43 psi (with a fuel pressure regulator). I don't need a 43 psi secondary pump do I? Will any psi fuel pump work as long as it's not more pressure than the FAST fuel pump? What if I used an electronic fuel pump that was only 4-7 psi, that is used for carburetors? Would that work or do I need a EFI fuel pump that pumps the same amount of psi as the FAST fuel pump?

As for the return style fuel system, I need to run a return fuel line to both tanks so I don't pump returned gas into a full tank that I'm not using. So my train of thought here is to install a "Tee" in the return fuel line and run it to both tanks. So if one tank gets full from return fuel, it will be forced to feed into the other tank....Am I on the right track here? Will this work????

I have been asking these questions to the staff at FAST and they aren't much help because he states that he's never experience a dual tank setup installation so he's not sure how to do it. Also, it's my assumption that they don't want to advise me on how to install it and then have something go wrong with the risk of being held legally liable. Not that I would do that, but they just have a CYA attitude, which I don't blame them. So this is why I need your help....Thanks..

I plan to go EFI with my 70 but haven't decided whether to go with FAST system or MSD Atomic.

I'd run a separate FAST pump for the aft tank... not simply a lift or "priming" pump. Its not the pressure that would be my concern... it's the volume.

Return lines.... I don't think the tee will work correctly and force feeding either tank could result in overfilling... again, it's the volume of fuel. I suggest a fuel solenoid valve that switches the return line to feed the tank that is being used.

u need a 6 valve switcher,check holley.com

I would just mount it as close to the fuel tank selector valve as possible and just try it? See how it runs.

HIO Silver---the MSD Atomic is not a return fuel system, the FAST is. Had I realized this I probably would have purchased the MSD system simply so I didn't have to plumb a return fuel line...

So you're advising to run another Fuel pump with the same fuel volume as the FAST pump ?

Run a fuel solenoid valve? Would I wire this into the "Y" junction or the toggle switch on the dash? How do I hook this up?

400 .040 Over---What is a 6 valve switcher and what does it do? What's it used for? Is this for my return fuel line issue?

J Ballan---I already spoke with FAST and they stated that if the fuel pump is farther away than 20" from the tank, it will damage it. These type of fuel pumps are "pusher" pumps, not "puller" pumps. They work off of gravity to be fed, then pushes the fuel up stream...Since this system cost me $2300, I don't want to just hook it up and see what happens.

Yeah, I know the Atomic is PWM and thus does not require a return.

Ideally, I'd run two complete fuel pump systems - one for each tank and switchable. The in-cab tank selector switch would select the tank, activate the correct pump, and switch the return line.

Use a three-port fuel solenoid to serve as the tee .. one inlet, two switchable outlets like this one: 3 Way Fuel Solenoid Valve 12v SVO WVO Bio Diesel | eBay

OR... let gravity do all the work and run the auxililary and main tanks in parallel and not switchable.

You have to run two pumps I "had" a Holley Projection on my truck... with duel tanks and they wanted one on the front one on the rear with the duel tank feed return feed,You can piece it together by getting a new injected truck plunger and a Subaru external pump....

Holley 534-37 - Holley Dual Tank Fuel Pump Kits - Overview - SummitRacing.com to say but I didnt use my front tank...

I was very disappointed with the fuel mileage 7-8 but it ran great.

Then changed it to a diesel now Im getting 14.5-15.0 with the turbo feels just like my V8...Just smells funny!

I hear ya. Most pumps are better pushers than pullers. IMHO getting the fuel up and out of the tank would be the hard part, an extra 20'' or so wouldn't be a big deal. Asuming the lines are in good shape so it wont suck in air and cavitate the pump.It would also keep things simple. This is just my opinion, I've been wrong before. Just ask my wife. Ha ha.

Had someone suggest this.....hook up a fuel pump to the rear tank and plumb it to the main tank, so it fills the main tank, activated by a toggle switch. And just set up the FAST fuel system to run off one tank like it's designed to, which would be the main tank. This sounds alot less complicated to set up. Your thoughts????

That would work fine and it would be fairly simple to do.

Hmmm... a transfer pump? That would work but I'd be leery of forgetting to shut it off and burning up the pump.

So how would ya know when to shut it off? By the level in the main tank or do both tanks each have a sender?

Both tanks have a sending unit, so I can read the fuel level on both tanks....
Had a question about the 3 Way Fuel Solenoid Valve 12v SVO WVO Bio Diesel....will this work with regular gasoline? I assume it will since you suggested to use it, but when I looked at it on Ebay, it didn't say anything about use with gasoline.

Ah. cool...

The 3-way....It cites it is compatible with gasoline (below).. Petrol=gasoline :
"
Valve details

• Precision made brass valve body with stainless steel internals.
• Operated by 12 volts dc 1 amp .
• Fitted with viton seals, compatible with hot diesel, hotVegetable Oil and hot bio diesel (and Petrol)
• Max temperature rating of fluids 120 deg C.
• Size 78mm high, 83mm long, 24mm wide, with fittings.
• Weight 150g each with fittings.
• 2 off M3 mounting holes in base of the valve."

Oh ok, thanks for clearing that up....

Although installing a fuel pump to pump gas from the rear tank to the main tank just to transfer the gas to the main tank would be a super easy installation; however, installing it with the 3 valve solenoid and 2nd high pressure EFI fuel pump for the rear tank doesn't seem to be that hard to install either. I might go this route, but need to think about this a little more first....Keep the advice coming. You're input is helping alot...

For the less than the extra cost of the second pump, plumbing ect. you could add a 38 gallon rear tank and do away with the second tank. That's what I would suggest. Simpler and more reliable.