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Thread: Holley Dual Sync Distributor Wiring

  1. #11
    Join Date
    Dec 2009
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    Connecticut
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    Thanks for the update/testimonial. These are the parts I often suggest and, this is the satisfaction most Sniper EFI users experience.
    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

  2. #12
    Join Date
    Oct 2016
    Location
    Middle River, MD
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    249

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    Quote Originally Posted by 30rat View Post
    I finished the Holley Dual Sync Distributor install tonight, and here's my review:
    The Sniper EFI was a straightforward install other than upgrading the fuel system,
    which was just time consuming depending on which way you go with it.
    Night & day difference in throttle response & power with EFI. I give it an "A".
    The Holley Dual Sync Distributor is also a simple install, once you get the 558-493 Adapter Harness.
    Simply plug it into the ignition harness, purple to purple, green to green, red to switched +12V.
    If running an MSD box, plug in the 10-pin connector and connect the white wire to the MSD white wire.
    The 30_Rat (Instagram name) fired right up, and I can't wait to hit the strip with it. My grade is an A.
    Quote Originally Posted by Danny Cabral View Post
    Thanks for the update/testimonial. These are the parts I often suggest and, this is the satisfaction most Sniper EFI users experience.
    Great to read. Congratulations on the smooth installation.
    My harness should be here today, but as luck would have it, the Dual Sync is showing as backordered.
    Looking forward to a smooth install with the Holley Dual Sync, and running the Timing Control myself.

  3. #13
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    Quote Originally Posted by rel3rd View Post
    My harness should be here today, but as luck would have it, the Dual Sync is showing as backordered.
    I wish you hadn't cancelled your original Holley Dual Sync distributor order. However, I wish you the best with your Sniper ECU controlled timing upgrade.
    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

  4. #14
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    Oct 2016
    Location
    Middle River, MD
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    Quote Originally Posted by Danny Cabral View Post
    I wish you hadn't cancelled your original Holley Dual Sync distributor order. However, I wish you the best with your Sniper ECU controlled timing upgrade.
    Well, it seems the HolleyInjection.com site is now a dead link...at least it was yesterday.
    If you Google them, and click on their website, it goes directly to Holley.com.
    Anyway, no biggie, it's supposed to ship in 1 week, and thanks for the wishes.
    Unfortunately, another more serious issue has popped up. I'm starting a new thread here in a minute. Nothing at all related to distributors, timing, or harnesses.

  5. #15
    Join Date
    Oct 2016
    Location
    Middle River, MD
    Posts
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    I thought I already posted this, but as usual, I'm a little confused.
    The original poster said harness from dual sync, purple wire plugs into Sniper EFI harness. Green wire to ground and red with white stripe to +12V ignition.
    But just above says purple to purple, green to green. So does green go to ground, or somehow get connected directly to green on the Sniper EFI harness?
    FWIW, I have the same harness. Where purple wire is terminated (by itself) to the small two terminal plug, but green wire is loose, unterminated, by itself.
    I know the red one is 12 volt with key-on, but unsure of the green. Thanks in advance.
    Last edited by rel3rd; 12-25-2016 at 08:54 AM.

  6. #16
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    This YouTube video should be correct for wiring the Holley Dual Sync Distributor, 558-493 Adapter Harness & MSD CDI box:
    https://www.youtube.com/watch?v=ld9ml6e6P6Q (This Sniper EFI YouTube video has the correct wiring diagram @ 2:33 minutes.)
    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

  7. #17
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    Oct 2016
    Location
    Middle River, MD
    Posts
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    Unfortunately, the green wire is loose, with no terminal on it, or with the actual plug itself. I guess I could hardwire it to a connector by using an old MSD harness. Or may try re-purpose a terminal from my ever growing spare MSD parts box.
    Last edited by rel3rd; 12-25-2016 at 11:25 AM.

  8. #18

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    The Holley 558-493 Adapter Harness I received had loose wires as well. The connector that was installed on the purple was a male like the one off the ignition wire harness. I simply cut the connector off the purple wire and soldered & heat shrinked the wires.

  9. #19
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    This information is for anyone who wants to make or modify the Holley 558-493 Adapter Harness for a custom length fit, or wants individual parts for quick disconnect capability:
    The MSD 2-pin connector (LINK) is a TE Connectivity, Commercial Mate-N-Lok, Free-Hanging #1-480318-9 Plug Housing & #1-480319-9 Cap Housing.
    The other connector at the opposite end of the Holley adapter harness, is Delphi Metri-Pack 150 series, black ten cavity #12065425.
    You'll need a TPA (#12177082), three female terminals (#12160223), three wire seals (#15324976) & seven cavity plugs (#12059168).
    FYI: These Delphi Metri-Pack connectors are color coded with corresponding slots.
    If plugging into an existing connector, the color of the connector isn't a "choice".
    http://www.powerandsignal.com/docs/D...%20Catalog.pdf (Delphi Connection Systems Catalog - Page 2.17)
    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

  10. #20
    Join Date
    Sep 2015
    Location
    Palm Bay, FL
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    I realize I'm posting just a bit past this thread's prime, but I wanted to provide some updated information.

    The Holley 558-493 Adapter Harness, correctly manufactured, will have a 10-pin connector that plugs into the Holley Dual-Sync Distributor, a 2-pin connector that plugs directly in to the 2-pin crank signal connector on the Sniper, and only 1 loose wire which is connected to a switched 12-volt source to provide power to the distributor. A picture and ordering information is below, four are currently in stock:
    http://www.efisystempro.com/ignition...ibutor-558-493

    The Sniper installation manual, also mentioned above, has been updated and now contains the correct wiring diagram for the Holley Dual-Sync Distributor installation:
    http://www.efisystempro.com/image/ca...on-manual2.pdf

    The harness ships without any additional instruction, and if one is not paying close attention to the wiring diagram above, might plug the 10-pin female connector on the 558-493 into the 10-pin male I/O connector on the Sniper harness. That's not going to work. The Sniper includes a short sub-harness with a 10-pin female connector that plugs into the Sniper 10-pin male I/O connector. From that come the purple/green wires into a 2-pin connector that mates to the 2-pin connector on the 558-493.

    One final note. Best practice is to twist the purple/green wire pair on the 558-493 (as shown in the picture above.) I notice that the ones that are shipping now are not twisted, but it's a trivial matter to do so.
    Chris Myer
    800-880-0960 x654
    chris@EFISystemPro.com

    Check our www.EFISystemPro.com website for live stock status on
    all Holley items, including the full line of Holley HyperSpark Distributors!

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