Page 2 of 2 FirstFirst 12
Results 11 to 16 of 16

Thread: Fuel Pressure

  1. #11

    Default

    I’ll try that thanks. Had a Walbro 307, changed it and ever since I'm having that issue. I might put the old one to see it the new pump is the issue as the old pump always held pressure.
    Thanks guys.

  2. #12
    Join Date
    Jan 2010
    Location
    Brisbane, Australia
    Posts
    1,491

    Default

    Yes, the new pump has no check valve, and once it stops, the pressure bleeds back through the pump.
    Regards, Gary

  3. Default

    FWIW: I have in-tank Walbro 255 LPH (with Racetronix Turbo GN Sender) and it bleeds down after (Key-On/Engine-Off) pump prime. Not immediately to 0 psi, but slowly back down to 0 eventually in a matter of about 5 mins. Shoots right back up to 43 as soon as cranking starts, and never seen any issue from it. HTH

    HP EFI V4, 388cid Stealth Ram, 1000 CFM 58mm throttle body, Holley Dual Sync Distributor. LS Coil Near Plug, 1 bar MAP, 48 lb/hr Holley EFI injectors, 43 psi

  4. #14
    Join Date
    Dec 2009
    Location
    Connecticut
    Posts
    22,456

    Default

    Yep, my Walbro fuel pressure happens the same way. It's completely normal.
    May God's grace bless you in the Lord Jesus Christ.
    '92 Ford Mustang GT: 385" SBF, Dart SHP block, TFS TW 11R 205 heads, 11.8:1 comp, TFS R-Series intake, Dominator MPFI & DIS, 36-1 crank trigger/1x cam sync, 160A 3G alternator, Optima Red battery, A/C, 100HP progressive dry direct-port NOS, Spal dual 12" fans/3-core Frostbite aluminum radiator, Pypes dual 2.5" exhaust/off-road X-pipe/shorty headers, S&W subframe connectors, LenTech Strip Terminator wide-ratio AOD/2800 RPM converter, M4602G aluminum driveshaft, FRPP 3.31 gears, Cobra Trac-Lok differential, Moser 31 spline axles, '04 Cobra 4-disc brakes, '93 Cobra booster & M/C, 5-lug Bullitt wheels & 245/45R17 tires.

  5. #15

    Default

    My issue was a bad line from the pump to the sending unit in the tank.

  6. #16

    Default

    6.) Question: I’ve installed my new Aeromotive bypass regulator. Fuel pressure seems to adjust fine and holds great when the engine is running, but when I shut the engine off, pressure drops quickly to zero. Shouldn’t the pressure hold like it did with a stock regulator?
    Answer: No, Aeromotive EFI bypass regulators may not seal perfectly when the pump is off. They are engineered for the highest possible performance when the engine is running. https://aeromotiveinc.com/tech-help/...fi-regulators/
    Just an FYI if someone is reading this and has an aftermarket regulator. My MagnaFuel regulator behaves the same way. Annoying, but normal.

Page 2 of 2 FirstFirst 12

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
About us
Holley has been the undisputed leader in fuel systems for over 100 years. Holley carburetors have powered every NASCAR® Sprint® Cup team and nearly every NHRA® Pro–Stock champion for four decades. Now, Holley EFI is dominating the performance world as well as our products for GM's LS engine. Holley's products also include performance fuel pumps, intake manifolds & engine dress–up products for street performance, race and marine applications. As a single solution, or partnered with products from other Holley companies - Hooker Headers, Flowtech Headers, NOS Nitrous, Weiand, Earl's Performance Plumbing, or Diablosport - Holley products can give you the edge you need over the competition.
Join us