frustrated engine breaks up off idle

Discussion in 'High Performance Modifications' started by Mwilson, Dec 25, 2017.

  1. Mwilson

    Mwilson Veteran Member

    Installed new MSD Digital 6 Plus & Pro billet distributor no other changes
    per instructions and it idles great, start retard great, 2-step great but any acceleration or reving over 1,000 rpm and it starts popping & breaking up. All header tubes are hot plugs and wires fairly new as well went in with the motor a few weeks ago. car ran great with standard coil & hei

    red - ignition
    white - not used
    orange - positive coil
    black - neg coil
    violet & green - distributor
    heavy red - battery
    heavy black - battery
    blue - transbrake/two step
    pink - N20 activation timing retard
    green loop cut per instructions
     
  2. 80sz

    80sz Veteran Member

    2,238
    175
    Feb 2, 2014
    Buffalo,n.y.
    I don't like the ground to the battery. I'd have it on frame. Does timing advance with revs?
     
  3. Mwilson

    Mwilson Veteran Member

    I have it locked at 36 deg, I will try grounding to chassis as well
     
  4. mrdragster1970

    mrdragster1970 Veteran Member Lifetime Gold Member

    .


    Always ground directly to battery, or a lug that is directly to the battery.
    Never ground anything to the chassis.

    It sure sounds like you have a limiter engaged at 1000.
    Check all the limiter circuits for something left on.

    .
     
    Blown Camaro likes this.
  5. CorkyE

    CorkyE Veteran Member Lifetime Gold Member

    8,975
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    Nov 4, 2004
    Ringgold, GA
    I'm not familiar with that box, sound like mrdragster might be on to something. I accidentally set my 2nd limiter below the first, caused me a bit of ssue. Also since your just setting it up now, make sure the blue and pink wires aren't connected or grounding.
     
  6. Mwilson

    Mwilson Veteran Member

    its not quite the same miss as hitting the limiter its more random, it will physically rev up to about 3,000 but missing badly. I did disconnect the blue and pink & no changes. Also my red led is blinking and it says it needs to be a steady light
     
  7. Mwilson

    Mwilson Veteran Member

    there is a dial for V8 no start retard #2 setting or V8 20 deg start retard #6 setting I have tried both
     
  8. 80sz

    80sz Veteran Member

    2,238
    175
    Feb 2, 2014
    Buffalo,n.y.
    Msd grounded to batt caused a problem with my digital gauges. Made them erratic. Its running good but possible off 180?
     
  9. mrdragster1970

    mrdragster1970 Veteran Member Lifetime Gold Member

    .


    No clue about digital gauges, I'm old and still use the old style gauges.
    All I know is I never ground anything to the chassis for any reason, and have zero issues since.
    I run a computer, and lot's & lot's of electronics in all my race cars, a stable ground is key.

    Plus people forget, power in, power out.
    You must have the same load capability, and low resistance for the ground, you do for the power.

    OK, so it's jacked over 1000.
    1st, remove box to make sure you didn't screw up the dist, wires, plugs etc etc.
    If it runs smooth, add box with zero features engaged, if it stumbles, the box is broke or set up wrong.
    Add a new feature until it stumbles if it's not the box.

    AH, the joy of racecars :(

    .
     
    Blown Camaro likes this.
  10. Mwilson

    Mwilson Veteran Member

    now its not firing at all it just quit while It was running, no spark. tested per MSD instruction by jumping the 2 wires going to distributor and then removing the jumper it says the coil wire should fire but mine doesnt.
     

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