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Thread: Power Off Problems

  1. #1

    Default Power Off Problems

    When I cut the key switch power off, I'm having a delay. I don't have this problem with my HP unit, just the Dominator, and it's wired all the same. Is there a fix?

  2. #2
    Join Date
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    Default

    Quote Originally Posted by tnfastbusa View Post
    When I cut the key switch power off, I'm having a delay.
    What is the Switched +12V red/white wire connected to?
    http://documents.holley.com/techlibr...10555rev17.pdf (Holley EFI Wiring Manual)

    Also, if this is an electronic transmission control application, read below:
    http://forums.holley.com/showthread....9158#post59158 (Transmission Switch Power)
    May God's grace bless you in the Lord Jesus Christ.
    '92 Ford Mustang GT: 385" SBF, Dart SHP 8.2 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.

  3. #3

    Default

    An on/off switch, and I'm not using any transmission stuff. I have two different units, and the same switches. I even swapped them out, and the same thing. I'm getting a delay when the power is cut to the Dominator ECU. It doesn't shut off until 1 to 2 seconds, then it will shut off the engine.

  4. #4
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    Quote Originally Posted by tnfastbusa View Post
    An on/off switch... I'm getting a delay when the power is cut to the Dominator ECU. It doesn't shut off until 1 to 2 seconds, then it will shut off the engine.
    As a test, temporarily connect the Switched +12V red/white wire directly on & off the battery itself.
    If it works properly, then your ECU is fine, and we know it's your wiring or something on that circuit.
    May God's grace bless you in the Lord Jesus Christ.
    '92 Ford Mustang GT: 385" SBF, Dart SHP 8.2 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. #5

    Default

    This suspiciously sounds to me like something feeding back. E.G. conversions on (3-wire) Delco alternators used without resistors or diodes in the excitation/lamp circuit.

    I'm with Danny. Disconnect the "switched red" going to the EFI, and otherwise monitor the switch circuit with a meter to see what's happening.

  6. #6

    Default

    I can take the red/white wire straight to the battery (with it running), and still a delay when pulled. Nothing wrong with the wiring; I have two bikes with the exact same wiring, and the Dominator ECU still does it. I can even take the HP ECU off the other bike, and stick the Dominator ECU on the other bike, same thing.

  7. #7
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    Quote Originally Posted by tnfastbusa View Post
    I can take the red/white wire straight to the battery (with it running), and still a delay when pulled.
    Then you'll have to call Holley Tech Service (Link). Maybe your ECU is defective.
    May God's grace bless you in the Lord Jesus Christ.
    '92 Ford Mustang GT: 385" SBF, Dart SHP 8.2 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.

  8. #8

    Default

    Just talked to a friend, his is doing the same thing, but his is the HP ECU. Just crazy. I guess it's not causing any problems, it's just when you cut the power, there's a 2 or more second delay.

  9. #9
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    This is a problem with some other item in the system causing a delay.

    The way to sort it out, is to remove one item at a time and keep trying it.
    I would start by removing power to the fans one at a time.
    Then move to the alternator.
    Pull power from any devices that "Spin", as they are usually the problems.

    Also, if your alternator is not connected directly to the battery, it can keep things running quite easily. (This is often the issue people have with their shut off switch, as they often forget the alternator has to be on the battery side of the switch, and not on the power to the car side of the switch.)

    Once you find the problem item, you can add a diode to the power wire to prevent it from backfeeding & maintaining power.
    -Scott
    Don't forget to check out progress on my Race Car:
    Project Blasphemy - 8.07 @ 171
    Low 8 Second Street Car

  10. #10

    Default

    I was having the same issue, and narrowed it down to the electric fan feeding voltage back through the circuit. I would get a voltage spike of 17-18 volts for a second, before the engine would shut off. I solved the problem by installing a solid state relay, and controlling the fan via PWM.

    Mike
    1967 Camaro. 5.3L L33 swap, Holley Dominator EFI. 10.65 @ 128 so far.
    Rick's Tank with dual Walbro 450s, Holley 120 lb/hr injectors.
    LS1 intake, stock DBW TB, LJMS custom cam/BTR springs/Tick pushrods.
    TH400, FTI Converter, Fab9, 3.25 gears/Wave-Loc diff, 275/60/15 M/T ET Streets. 125 HP dry nitrous.
    Waiting to install Holley Turbo Manifold Kit: Forced Inductions Billet S485/Vibrant 18x12x6" A2A. Looking to go 8s this year.

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