DIY Custom fuel return system

Discussion in 'Engine DIY' started by mySIck, Apr 13, 2020.

  1. mySIck
    • 2019 Toys For Tots

    mySIck Well-Known Member

    Messages:
    2,179
    Location:
    FT. Bragg, NC
    Vehicle Model:
    Civic SI
    Body Style:
    Sedan
    Part one,

    here is a list of products you will need to complete your fuel return. (you WILL have to have a FlashPro or Ktuner for this). you can use what products you want but keep in mind it is possible to have leaks when changing brands from fittings and hose so I stuck with Vibrant thru out my whole system where it was possible.

    Fuel rail with gauge
    Fuel pressure regulator
    20' of nylon Braided flex hose AN-8, Part #11978
    10' of nylon Braided flex hose AN-6, Part #11966
    10' Push on Rubber Flex hose -6AN, Part #16316
    x2)Swivel hose end fitting X2 90 degree -6AN Part #21906
    x2)Swivel hose end Fitting 90 degree -8AN Part #21908
    Walbro 450 fuel pump
    Russell fitting Part# 641303
    Precision Fuel Filter PN:S15003
    Butt connector with Crimp, solder and heat shrink all in one (handpack PN:HP6640)
    AN-8 Fuel Cell Bulkhead adapter fitting with locking nut PNXXXXX

    You will also need,
    Hondabond Liquid gasket
    Dremel with cutting and sanding stone
    Drill with drill Bits
    8 pack of hose clamps
    Large clamp to hold pump to sending unit aprox 4"
    basic hand tools, you can also order a fuel door remover but is not necessary I found it was easy enough with a flathead screwdriver and hammer.
    Lots of zip ties
    Sharp scissors to cut Braided lines
    Parts I used:

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    Last edited: Apr 13, 2020
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  2. Honda-Fan
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    Honda-Fan Well-Known Member

    Messages:
    914
    Location:
    Dallas, Texas
    Vehicle Model:
    Civic LX
    Body Style:
    Coupe
    Oh, this is awesome!! Thanks, @mySIck !

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  3. mySIck
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    mySIck Well-Known Member

    Messages:
    2,179
    Location:
    FT. Bragg, NC
    Vehicle Model:
    Civic SI
    Body Style:
    Sedan
    Part 2,

    Getting started you will need to remove your back seats to gain access to the fuel sending unit. take off the hoses and power from the unit. I used a flathead and hammer to knock it loose. once the unit is out you will have to take it apart. the two rods have a little disk holding them on I pulled it off with needle nose pliers and put in a safe place. next you got to get the old pump unit out those squeeze tabs are a real pain I used a couple flatheads screwdriver's and a friends help for this part.

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    next is to remove the old pump and hose I cut mine out you will not be using them again.

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    this part of the sending unit will not be used anymore take the power connector out.

    now it is time to modify the sending unit. get a drill and large drill bit ready with your Dremel. I used the drill to start the cuts make sure you are CAREFULL the plastic is easy to split or brake so take your time.

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    I used the sanding stone to finish this. see the black fuel level also be careful with that to if you want to know how much fuel you have.

    now that you just finished sanding the bottom you will need to size up your fuel pump and filter. the filter will now hang below now.

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    once you have your placement it is time to drill 2 holes to hold the fuel pump in place and make sure it is in the meddle of the pump not bottom or top. i used 1 and it is holding A O.K but feel free to use 2 clamps if you like.

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    for the cap you will have to use the drill to cut a hole for the fuel feed (factory feed will now be the return).

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    I got really happy with the hondabond on this one. You can clean the top before but will need to be cleaned again before being put back in the tank.

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    Bottom side you the cap have ribs cut and sand them down flush onec finished install the AN-8 Bulkhead and at the top put the hondabond let dry.

    At this time you will need the Flex hose 16316 from pump to bulkhead and from old feed down the side held with clamps. make sure you clamp all ends and the old feed that is now your return will rune on the outside of pump. make sure you don't forget those little Disk that are easy to lose.

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    Ignore the electrical tape I will add a photo later with the proper way i did it for testing. You will need to cut the positive and negative and connect with Butt connectors as shown below.

    ***Pic Needed***

    check over all of you connectors are tight and get ready to put the pump back in the car and after that the hard part is over. Make sure no debris is present or any plastic hair is going to brake off in the tank.

    Part 3 continued below -
    https://9thcivic.com/forum/threads/custom-fuel-return-system.16363/#post-450750
     
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  4. webby
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    webby Administrator

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    thank you!
     
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  5. ron v
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    • Supporting Member

    ron v The Forum Idiot

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    Nice!!!!
     
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  6. mySIck
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    mySIck Well-Known Member

    Messages:
    2,179
    Location:
    FT. Bragg, NC
    Vehicle Model:
    Civic SI
    Body Style:
    Sedan
    Part 3 Running fuel feed lines:

    once you get your sending unit back in be careful of the wires.

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    your line is going to run this way following the fuel lines avoiding all moving parts and pinch points.

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    add your AN-8 90 degree fitting and make it tight.

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    hook remaining lines and make sure cap is on tight along with fittings. also make sure you lines don't have any kinks

    time to take the plastic shield coving the fuel lines off. you can use a trim tool or a pick and flathead to pop them out. there are also a couple 10 or 12 MM bolts under as well holding on the plastic cover.

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    Follow the fuel lines and make sure you use a ziptie ever 4-6 inches to secure the feed line. go above the subframe with the fuel lines keeping away from moving parts.

    at this time you need to remove the factory fuel rail and lines to the fitting near the firewall

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    Remove the green clip and add put on the Russel fitting

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    once you get your fuel rail removed it is time to add your new fuel rail and gauge with fuel regulator with AN-6 fittings on the regulator






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    run your AN-6 now to you factory fuel feed you just modified. I ran mine next to the head under the large wire pack that is connected to the valve cover. make sure your fittings are tight. next is to size up and cut the fuel feed line. I have the RBC intake Manifold so I ran mine underneath thru the middle to the fuel line. I gave mine about 8 inches of slack.

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    look over all your lines, fittings for any issues. since I went E85 on this I pulled all the gas out of my tank and added 3 gal of E85 for it to cycle thru the system before I filled my tank. on start up have a buddy present to help look for leaks check your pressure on the fuel rail.

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    I put mine to 50 PSI but ask your tuner where they want you to be. I really hope this is helpful to someone. I have a little edits to do and a couple pics to add. and if you have any questions I will be happy to help.
     
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  7. bigs251

    bigs251 New Member

    Messages:
    1
    So your feed line is going to the regulator and feeding into the driver side of the fuel rail and the one in the middle is going back to the tank?

    Sent from my SM-G988U using Tapatalk
     
  8. mySIck
    • 2019 Toys For Tots

    mySIck Well-Known Member

    Messages:
    2,179
    Location:
    FT. Bragg, NC
    Vehicle Model:
    Civic SI
    Body Style:
    Sedan
    Sorry for the late reply. I Have my fuel feed under the intake manifold going to the center of the rail.

    My return is coming off of the fuel pressure regulator. I used the factory fuel lines as my return.
     

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