EFI-in tank pump conversion

[mrmustang]

Ok, so still in the mindset to add an EFI system (either Weber-EFI, or Holley Sniper style) to ERA 2080, as such, and going into this knowing I'll need a return line, I'm wondering if the FIA tank can be (in car) retrofitted for an in tank EFI style pump (Walbro ?) and return line easily?

Anyone have information on this type of retrofit? Anything else I'll need to know going in to this? Helpful tips and tricks? Maybe some visual aids (I'm a picture/visual type of guy)?


Thanks in advance,


Bill S.

[G_Edmonds]

I can’t imagine how this could be done in car. You’ll need enough clearance to remove the old unit, and fit the whole new unit (which is basically the depth of your fuel tank) under the trunk floor. That is, unless you have a trap door in the trunk.

[Grubby]

I discussed the Holley Sniper type in-tank fuel pump with Peter for a 427 build. He noted you would certainly need to modify the tank in a 289 because there is virtually no clearance between the top of the tank and the body. The clearance to the trunk floor in the 427 was a lesser issue.

I concluded you could have a recess welded into the top of the tank to install the Holley fuel pump and thus get the needed clearance. It needs roughly 1.25" inches (if mounted on a flat surface it sticks up that much). It should be an easy job for a good welder.

Most late model cars no longer use return lines and Holley offers several in-tank units that are near OEM quality and don't need it.

John

[spdbrake]

I think if I got another EFI setup I'd use an Aeromotive variable speed control pump. (uses feedback to slow down at cruise and idle). Keeps the fuel cooler and the pumps last longer. Plus you can ditch the current low pressure electric pump if you have one.
This is the smallest of the units.
https://aeromotiveinc.com/product/br...ed-controller/
https://aeromotiveinc.com/product/sy...l-efi-3-5-gpm/

The return line can be tapped in the filler neck with one of these Moroso kits.
https://www.summitracing.com/parts/mor-65385

Holley has started offering variable speed feedback pumps as well.

[C5GTO]

For the EFI in my Cobra, I used an external electric fuel pump and brazed a SS tube into the fill pipe for the return line.



Seems to work just fine and no gas tank mods required. The above was a recent modification as prior I had plumbed the return line into the tank vent. That configuration had issues as documented here: Gas tank becoming pressurized???

[eschaider]

Bill,

I don't know which brand EFI system you are looking into or which basic fueling model return style or returnless you are considering, so the following comments may cover some obvious ground.

The various in-tank fuel pump models available to you break down into two different families;

• The first is the return style employing a separate return line entering the tank at some convenient location on the exterior. Because you do not have an EFI tank, you will need to fabricate this entry.
  
• The second is the returnless style, where the pumps are installed in a vertical basket that enters the tank through its top surface and is sealed with an o-ring or other gasket and uses no returl line whatsoever.

There is any number of EFI providers that supply this type of pump 'basket' today. Many EFI system providers have incorporated design idiosyncrasies either intentionally or for lack of product design forethought that makes their fuel pump baskets favor their particular EFI product families.

I have a favorite provider for these types of components, that is EFI system and manufacturer agnostic. The provider is Fore Innovations. While they provide pump baskets that are bolt-in specific to the user's existing OEM fuel tank, it is also possible to use them with a weld-on flange for aftermarket fabricated fuel tanks. This is a link to their website and one of their Ford fuel tank multi-pump style hats. Click here => Fore Innovations

That particular pump basket is for a returnless style fuel system. Today that I am aware of the operating logic for that type of system is only available in OEM ECU's and MS3Pro ECU's from DIYAutoTune. All other ECU manufacturers will only provide systems with return-style fuel system logic.

If the election is to use a return style system, then the plug in the return line hole in the pump basket is removed and an AN fitting installed for your return line.

The Fore baskets will support any in-tank pump commercially available today. When you explore the pump options on his site, you will see the range of pumps available to you as the fuel system designer.

If you have a space consideration where the tank is too close to the trunk floor, you can build a mounting flange, with a recess allowing the basket to clear the flooring, that can be welded to the tank and use an angled fitting to attach the fuel line.

As I have mentioned in other postings, the MS3Pro EFI system can be purchased to work with an OEM Ford engine and under-dash wiring harness making the installation both more straightforward and less expensive while using a 100,000 mile OEM harness that will outlast yours and several subsequent owners, ownership of the vehicle.

BTW in the FWIW bucket, the MS3Pro plug-and-play systems come with an excellent base tune using the OEM Ford returnless fueling model. This is the MS3Pro system that both supports the returnless fueling model and also comes with the base tune as a stepping-off point. Click here => MS3Pro for Mustang GT

Here is a video of the install in a OEM vehicle that is litterally plug and play, click here => Mustang 1999-2004 MS3Pro Install

The video is 7:45 mins long.

This next video is the follow-on first start video after installing the EFI system in video #1. This video is 10:51 mins long.

Here is the video of the first start experience right after the install, click here => First Start Experience

You'll need the pump basket from Fore, the OEM wiring harness out of a 99-2004 Mustang GT, an FPDM (fuel pump driver module) and the FRPS (fuel rail pressure sensor) out of the same Mustang GT you got the wiring harness from, a set of aftermarket fuel rails and an MS3Pro PnP ECU from DIYAutoTune.

There are stunningly good 10 to 15-minute Youtube videos that do an excellent job of showing how the system is tuned. Of course, it comes with both tuning and data logging software so you can test, modify and check the results of your tuning efforts.

I hope this helps in your search.

[mrmustang]

This is for an ERA 289-FIA, the gas tank is mounted just behind the rear bulkhead, and not under the trunk floor area.

I have a new in the box Holley Sniper-550-510 that SWMBO gave to me as an early birthday present last night after dinner out with friends.

Will await a response from Bob at ERA and see if he has suggestions, or if perhaps there is a bung already in the FIA tank for a return line, which seems to be my major concern, as I must use a return line for this unit.

Uncertain what direction I'm headed at this time, but would hate to return the unit.


Bill S.

[eschaider]

Bill,

It's free — by definition, there is nothing that can compare!

I am unfamiliar with FIA fuel tank geometry.

Basically, in-tank pumps are the more desirable approach. The pump inlet(s) must always be submerged in fuel or the engine will stumble. Some smartly designed baffling around the fuel pickup, like we do on oil pump pickups, should take care of that for you.

If the tank geometry is tall and thin then you will necessarily end up building and installing some sort of in-tank mounting brackets to secure the fuel pump(s). If it is flat and wide you might want to look into the fuel hat approach that bolts to an OEM-style flange on the top of the tank.

[mrmustang]

I'm hoping that Bob will chime in with at least some helpful hints, maybe he(they) have a replacement sending panel that will have both a fitting for a return line, and still be able to have a working fuel level gauge. Trying my best to not have to drill tap a new orifice to the tank, as that would require draining and removal of the tank, Also hoping that Bob and Peter do not mind me posting these two pictures to this thread for clarity.

Having never had to remove or inspect a 289 FIA tank, it appears from the attached fuel filler diagram that there is a spacer of significant height (yes, I know it is on a lower area of the tank) to potentially allow space for a return line set up of some kind.

The tank itself is a 19 gallon, well baffled unit, so the current fuel feed is perfect.


Bob, Bob, Bob, anybody, anybody


Bill S.

[eschaider]

Bill,

The easiest way to plumb a return line is to use an AN bulkhead adapter through the side of the tank. Pick your location and drill for the size fitting you want. Use a gasketed washer from an industrial supply like McMaster or Grainger. Here are two examples from McMaster;





Either gasket is rated to seal 1000 psi or more, so properly sized, there is not likely to be a leak.

An alternative approach depending on the internals of the filler neck extension, would be to drill and tap an o-ring boss port on the filler neck below the cap seal and above the bottom of the filler neck. Use an AN fitting size that would fit in the space available, probably a -8 or -10 (preferred). Put the appropriate o-ring on the fitting, for its size, and screw it into the neck.

Either way does not require welding.

[strictlypersonl]

There is room to add a boss and fitting for a return (similar to the center pickup) at the back/bottom of the tank at either side. On the 427, we run the return line over the rear suspension and down, through the corner of the rear bulkhead and forward along the inside of the chassis rail.

[mrmustang]

Originally Posted by strictlypersonl

There is room to add a boss and fitting for a return (similar to the center pickup) at the back/bottom of the tank at either side. On the 427, we run the return line over the rear suspension and down, through the corner of the rear bulkhead and forward along the inside of the chassis rail.

Bob,

I'm thinking the return would need to be placed higher up so that the fluid was not under any pressure when returning to the tank. Clearly, I'm not expect when it comes to anything fuel injected, but I believe my thinking in this case is sound.


Bill S.

[xb-60]

Well, I learnt a long time ago that one shouldn't expect to be an expert at everything

[strictlypersonl]

Originally Posted by mrmustang

Bob,

I'm thinking the return would need to be placed higher up so that the fluid was not under any pressure when returning to the tank. Clearly, I'm not expect when it comes to anything fuel injected, but I believe my thinking in this case is sound.
Bill S.

As long as the return line is below the fuel level, even if the outlet is higher than the fuel, there is reverse pressure against the returning fuel. But, compared with a fuel injection's base pressure, that pressure head is irrelevant. Bottom Line: The fuel can be returned at any location into the tank.

[mrmustang]

Originally Posted by strictlypersonl

As long as the return line is below the fuel level, even if the outlet is higher than the fuel, there is reverse pressure against the returning fuel. But, compared with a fuel injection's base pressure, that pressure head is irrelevant. Bottom Line: The fuel can be returned at any location into the tank.

Thanks Bob, I'm going to hold off on the EFI conversion of ERA2080 for now, as something else has popped up that is already prepped for the Sniper I have sitting in a box. A new thread will be started accordingly.

Thanks to all who have responded.

Bill S.

[eschaider]

Your instincts were spot-on, Bill. I attempted to post this earlier today, but the website was uncooperative.

In the FWIW bucket, for a long time, today included, a school of thought has argued to place the return line near the bottom of the tank where it is impacted by the "g" forces acting on it from braking, turning and acceleration. When you do this, you place a variable pressure feedback in the return line that is equivalent to the amount of fuel in the fuel tank multiplied by the "g" forces acting on it. The pressure feedback is greatest when the tank is full and least when it is near empty.

Some fuel system architects take an agnostic, 'it doesn't really matter,' point of view. In the bigger picture, it will not turn the engine's fuel delivery system upside down. Still, it will place a variable back pressure on the system's fuel pressure regulator, changing the differential pressure across the injector without notifying the ECU.

The impact is essentially indistinguishable if you are tuning a drag race application. If you are tuning a daily driver or a road race car, then the driveability factor is impacted by the changing back pressure in the return line, and it can not be tuned around because it is a variable based on how much fuel is above the return port in the tank, whether the car is turning left or right, accelerating or braking.

The changing backpressure against the pressure regulator diaphragm modifies the measured pressure differential across the injector. The differential pressure across the injector is essential because it is what the ECU uses (along with several other metrics) to calculate injector pulse width. The injector pulse width calculation is critical to delivering the required fuel volume necessary to meet the target AFR the tuner has commanded for the engine under varying load conditions.

Is it the end of the world? Not at all. The engine will run either with or without the return line back pressure. The back pressure will, however, create a richer than desired fueling condition that the engine would operate better without. It is and becomes a part throttle engine responsiveness and driveability issue.

When you buy EFI fuel pump baskets from the major EFI system and component manufacturers, they will position the return line plumbing on the top of the fuel pump basket hat sometimes for simplicity, sometimes for correct fueling and sometimes for both.

I have included two pics of pump baskets below. One is from AEM, and another is from Fore Innovations. Both pump baskets include the return plumbing at the top of the hat. If you look at any other providers, they do the same thing, for all the reasons we have already covered.

If the fuel system designer does not use one of the commercially available pump baskets and places the pumps external to the tank, the fuel return should still be at the top of the tank. The most commonly expressed concern for this placement is the aeration of the fuel.

Fuel aeration is a red herring! Did you ever try to put the fizz back into a flat beer — it can't be done with the equipment any of us have at our disposal. The same thing with gasoline that you are attempting to add 'fizz' back into — it doesn't happen!

If the fuel system architect elects to use external pumps, it is very easy to put the return line anywhere they desire without welding. You use an AN style bulkhead fitting with gasketed washers from McMaster, Grainger, or one of the other industrial supply sources. The gasketed washers will withstand 1000 psi and more, so there are no leaks to worry about and no welding to do on a tank with gas fumes potentially still inside it.

Here is a link to a Fore Innovations fuel basket / hat,

Go to this URL => https://www.foreinnovations.com/Cobra_fuel_hat_p/55-800.htm and click the "Larger Photo" button in the middle of the page below the picture to see the top side fuel return used by Fore Innovations. You will clearly see the return port on top of the fuel pump basket.

The pic below is the Aeromotive approach to plumbing the return fuel line. Again you will find it on top of the fuel pump basket.

Is it a show stopper if you do not plumb it to the top — absolutely not! Will it improve your tune and the car's driveability at other than wide-open throttle? Absolutely, yes!

The in-tank pump, while difficult to implement in an FIA style tank, is the preferred pump location for feed, temperature control, vibration, and noise. Unless there is something I am missing about the FIA tank, your implementation will need to be outside the tank. It still works fine; Detroit plumbed their early systems this way for ten years or more before moving the pump inside the tank.

[sunman]

The Aeromotive pump above has a tube connected to the return fitting down into a fuel well baffle. Check out their install instructions.

“Fuelab tech tips: return line plumbing”, fuel aeration demonstrated.
Youtube video google it up.
Ed maybe link it.

Sniper EFI instruction manual, page 13, note 6 says it all with picture.
Google…

Kegs of beer are pressurized with CO2 for a few days and the gas dissolves into the liquid, forced carbonation. You can carbonate drinks at home with a Soda Stream.

Hey, two beer warning!!! We’re bout out

[mrmustang]

Part 2, and a slight drift elsewhere, in regards to the installation of the Holley Sniper EFI system, can be found HERE


Bill S.

[sunman]

Bill call Holley and Fuelab and let us know what they say about submerged return vs top of tank gasoline spray aerator.
Fuelab answers the phone with a tech guy.
Fix the title sell it again.
Good time for mrmustangco/ERA to do an EFI tank mod.

[eschaider]

In the end, the final decisions about how a member decides to build his car and its various systems come down to his own preferences and research. As the man spending the money, you need to do what you think is right for your build.

The Holley and Fuel lab information is compelling. Here is an old picture of the triple pump fuel basket/hat without the pre filter socks installed yet. It uses three 255 lph FGT fuel pumps with a fuel pump controller. As you can see, there is not a return tube protruding to the bottom of the pump location in the assembly.



I am not encouraging anyone to do something I have not studied and done myself. If you, as the builder, think you should have a return tube that positions the return fuel at the bottom of your tank — YOU are the final "decider" for your build. You should, by all means, do what you think is best for your build. You pay the bills; therefore, you are, by definition, the final authority on any build-related decisions for your car.

The information I offer on this site is “stuff” I have already done — which had expected/anticipated results without disappointments. You should take build paths and decisions that you feel are right for you and your car, notwithstanding what anyone says — certainly myself included.

Forums like Club Cobra are most beneficial when the members can share their experiences, so everyone does not need to travel the same and sometimes expensive discovery paths. Where possible, I share the discovery logic and testing that lead me to my decisions. You don’t have to do the same things; I am just sharing what I discovered that worked for me and could be helpful for others saving them the time and expense I paid for the knowledge.

In the FWIW bucket, a return-style fuel system without a pump controller will bypass nearly all the fuel the pump can produce at idle and part throttle. The use of a pump controller matches fuel delivery to engine demand much more closely than a pump running full tilt and dumping the excess at idle and part throttle back to the tank.

The presence/use of a pump controller, while a more sophisticated fuel system design and because it does not run pumps flat out, produces a more appropriate fuel delivery and a cooler in-tank experience for the gasoline and the pump.

In the end, again, you are the builder and the "decider"; you should do what makes you feel most comfortable so the build will meet your expectations.