MSD Digital 6 high rpm miss

Discussion in 'Electrical Systems' started by PaRoadDawg, Nov 14, 2006.

  1. PaRoadDawg

    PaRoadDawg Veteran Member Lifetime Gold Member

    1,089
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    Apr 10, 2002
    Shippensburg, PA
    Anybody else have a high rpm miss with their Digital 6? Mine starts coming in at about 5500. The rev limiter is set at 7000 rpm. Any suggestions or feedback would be greatly appreciated. It's a brand new unit, a brand new battery, the only thing I can think of is that the alternator is dropping amps up that high hence an electrical gremlin.
     
  2. clean79

    clean79 Veteran Member

    371
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    Jun 10, 2001
    Katy, TX
    Never heard of that before,

    could it be something else ?

    I would call MSD they have always been real good about helping you with their products.
     
  3. Rick WI

    Rick WI Veteran Member

    10,408
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    Jul 9, 2001
    Madison, WI
    I don't know if I'd suspect the alternator as they will either work or not work. In other words if it's not putting out the volts down low it won't up high either. Easy enough to check with a meter.

    I'd check the wires, rotor and cap though as a first step. I'll assume the plugs are in good order. That would be a simple list of things.
     
    Last edited: Nov 14, 2006
  4. PaRoadDawg

    PaRoadDawg Veteran Member Lifetime Gold Member

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    Apr 10, 2002
    Shippensburg, PA
    The rotor, cap, plugs, and distributer body are new. The only thing it might be is the wires. They're about 4 years old. Is there any way to check them or is it just something you have to replace and cross your fingers?
     
  5. gregh

    gregh Moderator Lifetime Gold Member

    My Mallory Hyfire VI-AL with a digital rev limiter started screwing up this summer. I had the rev limiter set to 6750 & it suddenly kicked in at 4700. I cranked it all the way to 9000rpm & it still wouldn't let me go over 5500.

    Mallory fixed it but I've been running for 3-4 months with out it & can't tell the difference so I sold it on Ebay.
     
  6. muscl car

    muscl car Veteran Member Lifetime Gold Member


    this sounds almost like the problem marv had with his nova a year or so ago and he checked everything and even tore the motor apart looking for the problem .his sbc would start breaking up around 6000rpm and i think it was eventually the valve springs that was the culprit . i would maybe talk with marv and find out what he did to figure out his high RPM miss
     
  7. Rick WI

    Rick WI Veteran Member

    10,408
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    Jul 9, 2001
    Madison, WI
    Sometimes a visual will spot tracking, burning or arcing. The only other way is to ohm them but it's not going to say too much as you don't have a baseline. If they read 5000 ohms though they are shot, that would be a VERY high reading. New high performance wires will ohm out in the 100 to 200 range. Accel yellow wires I have seen in the 1000 range.

    4 years is long for wires so would not be a total waste to replace.
     
  8. Turbo70Camaro

    Turbo70Camaro Veteran Member

    1,674
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    Jan 7, 2005
    so cal
    Did you gap the plugs, MSD recommends it to be alittle wider then normal.

    Jake
     

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