[HWYSTR455]

Just to say, there is a formula that helps determine the size of sump required for a particular HP level. The Tanks Inc sumps are based off SBC/LS type engines, and generally are only good to like 600-650 before they can run out of fuel. Pretty sure I've posted that formula here before.

I think there are 2 different sumps that Tanks uses, one is like .6 gal, the other one is slightly larger at I think .8 gal, would have to go through my notes.

You're pump, HP level, running PSI, fuel lines, and 'operating conditions' all play a part in the calculation of the sump size.

I've posted info regarding the senders too, the crappy ball float Tanks usually sends with their' tanks is junk. Not only can there be issues with additives, but because of the size of the ball, the arm needs to be so short, all the granularity is removed from the sender.

I've used the float/arm type that has the rectangular/oval float with success. If you want to get tricky, you can use wire to limit how that float 'spins'. It can in use stand 'upright', and give funky readings, but if you realize what's going on, you can live with it. The arm length can be about 3" longer using that float.

There's a couple float/floatless options, to name two, one is a type that uses resistance, another uses a vertical float inside a tube.

The resistance one is ordered to 'length', so you have to measure carefully, mounting to floor, and order appropriately. They only make those in 1/2" increments, and you need to take into account that the floor of the tank can get damaged in use. Usually, to be safe, you end up not reading the last 1" - 1.5" of gas in the tank.

The float in a tube type you order to length too, and basically the same conditions apply as the floatless resistance one. It can stand a little more damage than the floatless, but the float can hang in the tube.

Both you don't want to leave sit for long periods of time with less than a half a tank, crud can booger them up (it's a technical term). Best to fill the tank before you park for long period, or run it dry and leave the cap off.

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[Scott65]

In my case, IF the pump were performing as expected, it's more capacity than I require currently.

[Tom Vaught]

Originally Posted by Scott65

In my case, the tank is FULL. There's no possibility of slosh. Its something to do with the pump. Bad pump, cracked line, who knows. I'll figure it out eventually. Of note, it puts up good pressure under light load. Put your foot in it and it drops pressure by 50%...

How large of a feed wire are you using to drive the fuel pump?
Tom V.

[Tom Vaught]

64 GTO fuel tank fuel tray capacity:

"EFI-style internal baffling with 4.3 liter internal fuel tray to prevent fuel pump starvation."

Since you have a Firebird your Fuel Tray Capacity numbers will be different vs my 64 GTO tank.

Some simple math:

946 cubic centimeters of liquid = 1 quart
4 Quarts or one gallon = 3784 cubic centimeters.
A liter = 1000 ccs or in this case the 4 quarts = 3.784 liters.

My 64 GTO EFI Fuel Tank holds 4.3 liters of fuel in the Fuel Tray
A liter again is larger vs a quart.
So my fuel tray capacity is 1.136 Gallons of fuel not 6 tenths of a gallon or 8 tenths of a gallon of fuel in the fuel tray, as you have posted, but actually 1.14 gallons of fuel.

So a generic statement on the Tanks inc fuel tray capacity might steer some people wrong on the path to fixing an issue with the fuel system.

Tom V

[Scott65]

12 gauge wire, about an 18 inch long run. I do know it's pulling 20 amps while running. Not sure what it should be, I'll have to dig for that info, it may be a clue.

[Scott65]

That amps draw is at idle, 270kpa, or ~39 psi.

[HWYSTR455]

Interesting Tom, I'm going to have to look now, I'm curious which I have. The A-body I recall has a little bit bigger of one than the 2nd gen F, but I've never actually measured them. Those numbers I spit out were straight from memory, which isn't as good as I'd like to be anymore!


.

[Tom Vaught]

Originally Posted by Scott65

12 gauge wire, about an 18 inch long run. I do know it's pulling 20 amps while running. Not sure what it should be, I'll have to dig for that info, it may be a clue.

When we had issues with the fuel supply on our 740 HP 4.6L Mustang 4 valve Boosted (Vortech) engine, I ran a 10 gage wire from the battery (battery was in the trunk) to a 40 amp relay and then to the Kinsler Fuel Injection supplied Electric Fuel Pump and used the factory fuel pump wire to control the relay.

Fuel supply issues then disappeared.

Tom V.

18 inch or 18 foot run of wire? Battery in the trunk?

[JLMounce]

Originally Posted by Scott65

12 gauge wire, about an 18 inch long run. I do know it's pulling 20 amps while running. Not sure what it should be, I'll have to dig for that info, it may be a clue.

Yeah, something isn't right with that. I believe you are running a Walbro 340lph pump correct?

Here's the flow and voltage/amp draw chart for that specific pump.

http://www.tanksinc.com/pdf/5_Series...Flow_Chart.pdf

If you're running this at 39psi, you shouldn't be drawing anywhere near 20amps.

If the pump is actually seeing that type of amperage it's not flowing well at all which is again probably why you're starving for fuel. Since you state this is occurring at idle when demand is low, I would be looking at a possible wiring issue or an issue or a failing pump.

If you were seeing normal amp draws for around 40psi of pressure at idle and it spiked when you laid into the throttle, I would definitely be looking at fuel starvation.

How old is the pump you're using. Are you using it as a dead head PWM type setup or is it a recirc system all the time?

[Scott65]

Pump is new, issue was there at installation. The 39 psi is at idle, vacuum referenced return style regulator. I'm not at all concerned about the wiring, its sound. 18inches of wire Tom, from a 40 amp relay fed by 8 gauge wire from battery disconnect(switched main power) Yes the battery is in the trunk.

[Tom Vaught]

The Bosch 044 pump was flow tested at Kinsler and at 70 psi could flow 300 liters per hour. It also did that at only 10 amps of current draw. 20 amps???? Wow.

Tom V.

https://kinsler.com/Shop/product/bos...ump-in-line-2/

[krisr]

If I read correctly it's the 450LPH Walbro pump Scott? Those things pull ~18A so yeah 20A rounded up. I don't think you have a voltage supply issue, 12GA wire should be fine, just make sure your +VE and -VE wires are the same size and the -VE returns to the battery. Does the fuel return back to the tray near the pickup of the pump? Something sounds totally off as that pump should be good for around 700hp without breaking a sweat @ 60psi. Even more at 40psi. We just setup 2 of them (1 is staged using a hobbs switch) in a friend of mines Turbo LS car because 2x Bosch 044's weren't keeping up. Totally fixed his problem but we mounted the pumps at the rear most point in the fuel cell.

What filter/strainer is on the pump? is the pump wedged into the bottom of the tank potentially blocking the inlet?

[Tom Vaught]

The 450 Liter Per Hr Walbro pumps are 30+ years newer technology (2019 vs 1986) when I used the Bosch 044 pump in the Boosted Mustang.

And it does require AMPS to do Fuel Pump work. Looking forward to seeing what the results of your investigation comes up with.

Tom V.

[Scott65]

Mine is a 400lph Walbro. It's possible that it's too tight to the bottom of the tank... I didn't want it sitting too high. I'll do some flow testing when I get the chance, before I drop the tank and pull the pump. I'll update when i do.

[Tom Vaught]

We had to play with the hanger to get it right when we installed the 400 LPH Walbro fuel pump in my Tanks,inc fuel tank.

Tom V.

[Scott65]

I understand Tom. The screen being pinned forces a choice of only a couple spots, dictated by the bolt hole circle alignment...

[Tom Vaught]

I had actually had discussions, with the fabrication shop I work with, to remove a 5 inch diameter piece of metal where the current single 400 LPH GAS fuel pump mount is.

That would allow me to install two of the 450 LPH EFI pumps in the tank and clock them so that the fuel sender would work properly for my 64 GTO. Problem is I want Ethanol compatible fuel pumps designed with the right flow capability.

Still checking to see how many real Ethanol resistant fuel pumps are out there. So far the 450 pump is the lowest flow rated E-85 pump of the 3 I have found.

Tom V.

[Scott65]

If I can't prove beyond doubt this pump is ok, I'm gonna change to the E85 450 myself.

[Tom Vaught]

I had two vehicles for several years that ran great. A "last year" Windstar and a "almost last year" Ranger Supercab. The gas pumps went to E-15 gas in Michigan and with-in a year both vehicles had Fuel Pump failures after many years of perfect driving. $1000 to get each one back on the road to where I could sell them.

Not doing that same deal with my 64 GTO (on the road) with a "non ethanol" fuel pump.

How long have you been driving your vehicle with the fuel pump you have in there now?

Tom V.

[Scott65]

It's made about 4 short trips around town for testing. Most accounts say the Walbros are tough. Many people saying they use the popular 255lph pumps in ethanol (E85) service and get reasonable life from them. I would hope our E10(max) stuff wouldn't cause an issue in less than 100 miles(conservative on the high side). But who knows...