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Thread: Fuel Pump Speed Control. Why doesn't the EFI support this?

  1. #1

    Default Fuel Pump Speed Control. Why doesn't the EFI support this?

    I'm flabbergasted that Holley EFI doesn't provide support for fuel pump speed control out-of-box. This seems like an absolute no-brainer feature for the EFI computer to provide; please consider this a feature request. No need to have the increased noise, pump wear & tear and fuel heating/vapor lock issues if the EFI unit can intelligently just throttle the fuel pump. I'm assuming this has been discussed here before? Adam

  2. #2

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    Hi Adam, they do "provide support" for it in a way. You can create a custom PWM Output to run the fuel pump (via a speed controller), but then you can't reuse pin 2 on connector J1A for anything else. Which is a pain when you don't have many Outputs to spare. Also if you still want the five second prime before startup you need to use up yet another Output to achieve that.

    I can see why they use a straight +12V output though, if that was PWM by default they would get a ton of complaints from people hooking it up to a non-solid state relay and wondering why it didn't work. I just wish I could unlock the unused output at A2 so I could use it for something else?

    How is everybody else setting up their PWM fuel pumps? I have my primary pump on a PWM table with "Throttle Position" vs "RPM" on the X & Y axis, but I'm wondering whether "Fuel Pressure" or "Ethanol Content", or some other factor should have a say in the matter? My secondary fuel pump was going to be a straight +12V Output triggered by a drop in fuel pressure, but now I'm not sure if I will even run a second pump? Maybe I could use the secondary pump to do the five second prime?
    Andrew

  3. #3

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    I have a twin pump setup. Car runs on one pump, the second pump turns on past 50% TPS, 3000 RPM, or 5 PSIG of manifold pressure.
    89 Mustang GT
    Dart Block 363 with Borg S475 Turbo
    Holley Dominator EFI with 7" Digital Dash

  4. #4
    Join Date
    Dec 2009
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    https://www.holley.com/products/fuel...ess_fuel_pump/ (Brushless 2-Speed Fuel Pumps & Controller)
    May God's grace bless you in the Lord Jesus Christ.

    '78 BRONCO: 508" stroker, TFS heads, 11:1 comp ratio, Dominator MPFI & DIS, cold air induction, Spal dual 12" fans/aluminum radiator, dual 3" exhaust/Magnaflow mufflers, Moroso vacuum pump, Accusump, engine oil & trans fluid coolers, 100HP progressive dry direct-port NOS, A/C, LenTech Strip Terminator wide-ratio AOD/2500 RPM converter, 3:1 Atlas II, modified Dana 44/60-lockers-4.10s, hydroboost/4-disc brakes, ram-assist/heim joint steering, Cage long radius arms, traction bars, 4" Skyjacker lift, 35" mud tires

  5. #5
    Join Date
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    Chicago IL
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    Quote Originally Posted by Danny Cabral View Post
    https://www.holley.com/products/fuel...ess_fuel_pump/ (Brushless 2-Speed Fuel Pumps & Controller)
    Those are not a PWM controlled pump. They are 0%, 50% or 100%, nothing else. You either have +12V to turn it on 100%, or you have +12V and an additional Ground to make it run at 50%. Not other variations. On the dual pump version, you do it per each pump.
    -Scott
    Don't forget to check out progress on my Race Car:
    Project Blasphemy - 8.07 @ 171
    Low 8 Second Street Car

  6. #6
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    Quote Originally Posted by S2H View Post
    Those are not a PWM controlled pump.
    Yes, I know. It's basically a 2-speed pump. I was just presenting another option.
    May God's grace bless you in the Lord Jesus Christ.

    '78 BRONCO: 508" stroker, TFS heads, 11:1 comp ratio, Dominator MPFI & DIS, cold air induction, Spal dual 12" fans/aluminum radiator, dual 3" exhaust/Magnaflow mufflers, Moroso vacuum pump, Accusump, engine oil & trans fluid coolers, 100HP progressive dry direct-port NOS, A/C, LenTech Strip Terminator wide-ratio AOD/2500 RPM converter, 3:1 Atlas II, modified Dana 44/60-lockers-4.10s, hydroboost/4-disc brakes, ram-assist/heim joint steering, Cage long radius arms, traction bars, 4" Skyjacker lift, 35" mud tires

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