Fitech EFI install input needed

Fuel and Air Systems

  1. Mstone68440RR

    Mstone68440RR Well-Known Member

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    This past Saturday I finally got around to starting the install of a Fitech EFI system on my Roadrunner. Drained the fuel from my tank and removed associated fuel pump, filter and lines. Installed to supplied filter and EFI pump along the frame rail, ran the EFI hose to the inline filter and carb with no issues. Previous owner had installed a Moroso fuel pump, regulator and 1/4” (?) return line using metal lines with a shirt piece of 3/8” fuel hose to one of the vent tubes at the tank.

    The original vent line to the tank is a tiny 1/8” (?) barbed stem, doesn’t seem adequate for the return line, not to mention the hose size diameter difference. I don’t think this is a secure transition from the return line, at 50 + psi?

    Any suggestions for the return at the tank, do I need to add a larger port for the return? Shouldn’t it extend into th tank a ways to prevent aeration close to the pick up?

    I am not opposed to upgrading the stock tank to a newer replacement if needed, mine has a few dings and dents as well as being old. All the stock replacements I find offer the same vent configurations. Curious as to how others have plumbed the return?

    Another issue was The was the throttle cable attachment to the the throttle body, neither the stock hardware I have, nor the Edelbrock Mopar adapter seem to provide the correct attachment and travel. I don’t see any offerings on the Fitech site, what worked for your application?

    Thanks in advance,

    Mark
     
  2. matthon

    matthon Well-Known Member

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    I went with the tanksinc tank, in tank pump, 'corvette' filter/regulator on the frame rail near the tank, makes for a short return.

    Stainless covered teflon fuel lines, an fittings.
    Return has little to no pressure, but kept it the same size.

    Lokar, I think, makes a FiTech throttle bracket, not cheap, but worth it, although extremely simple in design, could make it. Check summit.
    Comes with springs and a tab on the bracket with 2 holes, useless as the tb has a return spring built in.
     
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    • 1 Wild R/T

      1 Wild R/T Well-Known Member

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      On the throttle bracket I used a Holley Mopar bracket.. Had to modify it a little but it works perfectly....

      I also went with a Tanks Inc fuel tank with a Walbro in tank pump, I didn't use a Corvette filter, I did use two new 3/8" lines from the tank to the throttle body, supply & return, I used compression fitting to go from the steel lines to A/N style fittings IMG_2775.JPG IMG_2768.JPG IMG_2637.jpg IMG_2622.jpg
       
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      • vance.dykes

        vance.dykes Well-Known Member

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        replace the sending unit with a built in return . redo the vent line as the system will need a good vent system or you will have problems.
         
      • hanks73340

        hanks73340 Well-Known Member

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        I just recently installed the Fitech Go Street 400. Your gonna want to use the 3/8 lines both ways because of the PSI. You'll enjoy the performance when completed.
         
      • vance.dykes

        vance.dykes Well-Known Member

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        look at a factory fuel system they use a 3/8 feed and a 1/4 return there is a benefit from this as a restriction on the return to help the regulator steady on pressure.
         
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        • hanks73340

          hanks73340 Well-Known Member

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          You are correct. I forgot to mention the lines tappering to 1/4. I'm getting old.....:screwy:
           
        • matthon

          matthon Well-Known Member

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          I believe the factory uses a smaller return to be cheap, a larger one is not needed.

          Why would the regulator care what size the return is, it regulates to a set psi and bypasses the rest to the return.

          My pump runs 100psi + unregulated.
          The regulator keeps the line pressure to the tbs at 58psi, whether I'm idling in traffic or full throttle.

          PTFE is the braided stainless teflon fuel line.
          It is incredibly easy to put the fittings on, but I did buy something to cut it with to ensure an even and clean cut.

          Check for an RPM noise error code, if you get it you'll need to shield some wires, ground one end.
          Keep wires separated, don't run the alt charge wire alongside the FiTech wiring, etc.

          I put in a new fusebox as well as a positive hub and a negative hub to avoid multiple splices, provide a solid power source and ground.
           
        • vance.dykes

          vance.dykes Well-Known Member

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          hay e-z on the old stuff we are wise !!!
           
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          • vance.dykes

            vance.dykes Well-Known Member

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            OK so fitech ask for a 1/4 return on some of the systems and the factory and Holley and pro-flow all want a return you tell me why
             
          • matthon

            matthon Well-Known Member

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            It was more of a rhetorical question, but to be clear a return is definitely needed. Manufacturers typically list a minimum size return line as it has to be large enough to return the fuel at little to no pressure.
            It's more related to pump size than the tbs.

            Also, never use efi rated rubber hose with an in tank pump. It's not rated to be submerged and will turn into jello.
             
          • vance.dykes

            vance.dykes Well-Known Member

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            a return line is more for keeping the fuel pump cool. a return-less system has to be pulse generated and or built in regulator return in tank
             
          • Mstone68440RR

            Mstone68440RR Well-Known Member

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            Thanks for the pics, they will help a lot, I might even be able to modify my Edelbrock adapter, looks similar. I like the ideas of the corvette regulator and shorter return line to the tank. That will solve a few issues.

            I don’t have the budget to get a new EFI tank with a submerged pump until later this year, so I will try to make my tank work until then. The tanks inc tanks look nice, anyone using the float less sending unit? Happy with the readings?

            I plan to add sub frame connectors later this year as well, which will probably mean rerouting the fuel lines anyway, so I can tackle that project at the same time I replace the tank.


            Thanks for the all the input and advice
             
          • biomedtechguy

            biomedtechguy Accelerati Rapidus Maximus FBBO Gold Member

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            If I can jump in here, I have the 6bbl/Hemi factory 3/8" tank to mechanical fuel pump line, and the factory 1/4" vapor return line. If I were to go 3x2 Throttle Body DPI or use the FiTech 3x2 TBI system, would the 1/4" vapor return line suffice as a fuel return line? Is the 3/8" line big enough to feed the EFI system?
            Thanks.
             
          • 1 Wild R/T

            1 Wild R/T Well-Known Member

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            Well since that system is only rated for 600 HP and according to Walbo the 3/8" line @58 PSI with the right pump will support 1000 HP... I'd say your fine...

            Return side is probably fine too, only concern is it may be a little restrictive and cause fuel pressure to rise... But you can also modulate the fuel pump speed to reduce flow... So it should be fine..
             
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            • biomedtechguy

              biomedtechguy Accelerati Rapidus Maximus FBBO Gold Member

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              If not for having just dropped $1,400 parts and labor to Promax to have them rework my 3 Holley 2bbl carbs, install all of their parts, the upper and lower stainless steel braided fuel lines, and run them on their dyno mule, I would have likely already switched to the FiTech 3x2 system, which I found out about only a week or so after sending out my carbs.
              The other thing is I plan on building a 6XX HP and hopefully 650 torque stroker motor, and I am leery about running the FiTech at full capacity, so I may look at the much more expensive, but also much more flexible F&B 3x2 DPI system when that time comes.
              The Promax modded Holley carbs are not going to hold me back on power with the stroker motor, and that may well be the fuel system I stay with, especially since I've learned some important tuning capabilities.
               
            • 383man

              383man Well-Known Member

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              The thing to remember on the return line and even more on an EFI system running 58 to 60 psi is you don't want it to small. Bigger is better to a point because the regulator must return the proper amount of fuel to the tank to maintain the correct fuel pressure. And on an EFI it can return a good bit of fuel at times so if the line was to small and was a restriction the fuel pressure would be to high. If the lines to large then thats fine because the regulator just needs to make sure all the fuel it bypasses to the tank gets there without backing up causing a restriction that would raise the fuel pressure if the fuel was not returning fast enough. So if the return line is to big it wont hurt a thing but if to small it will cause the pressure to go up.

              We just put the Holley Sniper on my sons Dart about 3 months ago and we put a new fuel tank in it that looked just like the stock tank and bolted right in but it had the fuel pump in the tank and that is by far the best way to go with an EFI setup. Ron
               
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              • vance.dykes

                vance.dykes Well-Known Member

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                yes as 1 wild r/t has said that would work perfectly.
                 
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                • 451Mopar

                  451Mopar Well-Known Member

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                  First, before connecting fuel lines to the fuel rails, connect the supply and return together and turn the pump on to flush the lines out. You don't want any debris from making the lines to get into an injector or the regulator.
                  If you put a fuel pressure gauge before the return line, with the lines connected, it will tell how much pressure is created by restriction in the return line. The higher volume the pump is, the larger the return line needs to be to reduce pressure. Return line size is more important when setting up a carb fuel system where the fuel pressures are around 7psi, not 40+ psi. I have used 3/8" supply and return, and 3/8" supply with 5/16" return. I haven't used 1/4" return, but I think it may work with a 225 LPH pump? I think the orifice hole size of the regulator is less than 1/4"? I think there is some notes about using an external regulator if running larger fuel pumps, but I tested my FiTech with a Walbro 450 LPH pump through the stock regulator (3/8" supply and 3/8" return on that one), and it controlled the pressures fine at 4-Bar (58-psi) on a 1200 PA system. I think current draw on that pump was around the 15-Amp max for the FiTech, so this size pump should be ran through a relay. I ended up using the Fi-Tech 340 LPH in tank pump. I think it was maybe 13-Amps, and compatible with the PWM control.
                  The regulator is referenced to manifold pressure, so if running a 4-bar regulator (58 Psi) you will have 58psi when the manifold has zero vacuum/zero pressure.
                  The regulator is maintaining a constant pressure across the injector, so the regulator in EFI will not be constant like in a carb application.
                  Under vacuum, the fuel line pressure will be slightly lower, and under boost, line pressure increases.
                  The current draw on the fuel pump increases with pressure, so if using boost, the fuel pump current is likely to be too great >15-amps for the internal driver requiring a fuel pump relay.
                   
                • bigmanjbmopar

                  bigmanjbmopar Newb with a view

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                  How does the unit work on your dual plane? any issues?
                   
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