BluePrint Engines

Visit our community sponsor

Thanks Thanks:  0
Likes Likes:  0
Results 1 to 4 of 4

Thread: EFI Fuel supply & return pressure regulation question

  1. #1
    Swapping out hot wheels:)
    Join Date
    Apr 2011
    Location
    Raleigh, NC
    Posts
    72
    Post Thanks / Like

    EFI Fuel supply & return pressure regulation question

    I have a 4.6L SOHC from a 97 Mustang GT that I'm trying to figure out the fuel lines on. I'm using an in-tank pump with return line. There seems to be two devices in the original lines (see circles in pic). There is a fuel rail pressure regulator and I'm guessing either a check valve or return line pressure regulator to hold back pressure on the rail before returning to the tank? Is that right? I'm thinking of 6AN braided hose to make the connections to the supply/return lines but the return device becomes an issue - do I need it? What do I replace it with (since I can't get the #%$@ thing apart)?
    FuelLines.JPG
    2025 May: MK5 Complete kit, Blueprint 347 EFI, 4R70W (current build)
    2019 Nov: '35 Hot-rod Truck, 306, EFI, 3-link (screwed by NC DMV)
    2015 Mar: MK4 Complete kit #8617, 302 create, carb, 3-link
    2014 Sep: MKII Kit #4215, 302 create, carb, IRS, Sold as roller
    2011 Mar: MK3 Base Kit #5400, 4.6L Fuel Injection, Daily driver

  2. #2
    Swapping out hot wheels:)
    Join Date
    Apr 2011
    Location
    Raleigh, NC
    Posts
    72
    Post Thanks / Like
    UPDATE: Doing some more web surfing, I think I found the answer. I believe that the return line on this engine normally has a check valve on it (righ circled item). The story is this maintains pressure on the rails when the engine is off. When you want to start it back up, you quickly have enough pressure on the injectors to start the engine. Without this I would have to cycle the key a few times in order to bump the pump enough to build pressure. Not having this valve might also cause lower fuel pressure at higher RPMs. Of course it's a very hard item to find. I'm checking to see if the new fuel pump I installed has a check valve in it (later model Mustangs did). Bottom line - I need to make sure the rails have pressure on them to get a good engine start. The left regulator makes sure the pressure is correct and the right check valve keeps it there.
    2025 May: MK5 Complete kit, Blueprint 347 EFI, 4R70W (current build)
    2019 Nov: '35 Hot-rod Truck, 306, EFI, 3-link (screwed by NC DMV)
    2015 Mar: MK4 Complete kit #8617, 302 create, carb, 3-link
    2014 Sep: MKII Kit #4215, 302 create, carb, IRS, Sold as roller
    2011 Mar: MK3 Base Kit #5400, 4.6L Fuel Injection, Daily driver

  3. #3
    Swapping out hot wheels:)
    Join Date
    Apr 2011
    Location
    Raleigh, NC
    Posts
    72
    Post Thanks / Like
    REDIRECTION: So even more web surfing and study of the Chilton book...maybe that's not really the return line, its probably the supply line. Also, I contacted the fuel pump supplier - they have a check valve on the supply port, not the return port (actually makes much more sense). I believe this is the real story: The pump supplies fuel to the supply with the check valve to prevent back flow when the pump stops. The on-rail pressure regulator is at the end of the line and relieves into the return line that runs unimpeeded back to the tank. This puts the correct pressure on the line while running and maintains pressure when the engine is off. Since the new pump has a check valve, the inline valve at the engine is not needed. Hope this might help anyone else trying to work with a 4.6L.
    2025 May: MK5 Complete kit, Blueprint 347 EFI, 4R70W (current build)
    2019 Nov: '35 Hot-rod Truck, 306, EFI, 3-link (screwed by NC DMV)
    2015 Mar: MK4 Complete kit #8617, 302 create, carb, 3-link
    2014 Sep: MKII Kit #4215, 302 create, carb, IRS, Sold as roller
    2011 Mar: MK3 Base Kit #5400, 4.6L Fuel Injection, Daily driver

  4. #4
    Senior Member
    Join Date
    Feb 2011
    Location
    Fort Lauderdale Fl.
    Posts
    3,296
    Post Thanks / Like
    I believe your correct in everything yuou have stated here...Steven
    FFR Daytona Type 65 Coupe
    67 427 Cobra
    57' Belair
    72 Pinto Wagon ,306" 1/4 miler
    34 5 window coupe Ford
    2003 Mustang GT
    99' ZX9
    85 Goldwing

    All toys still in the Scuderia!


    Every Saint has a past..................every sinner a future

    Don't take yourself so seriously........no one else does.

    You never see a motorcycle parked outside a Psychiatrists office.

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  

FFMetal

Visit our community sponsor