MSD grid

Discussion in 'PSI Superchargers Tech Questions' started by jrracing, Aug 23, 2016.

  1. jrracing

    jrracing Member

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    Having an issue this year not sure if it's the grid or something else, car back fires when you kill the motor 2 or 3 loud pops as motor shuts off. It's on a screw blown car with mag 44. Had command model last year with no issues like this before. Also if we pull to much timing out the car miss fires on #2 and 8 like it's hitting the Rev limiter. Any help would be great. Thanks
     
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  2. Mike Canter

    Mike Canter Top Dragster
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    Well if you shut the power off to the Grid then it can't be the Grid causing the backfiring that would have to be caused by unburned fuel igniting from something hot such a valve or header pipe. When you say you pull too much timing out you have problems on a couple of cylinders just how much timing are you pulling out and do you have a large or small mag cap?
     
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  3. Cadillac Lowery

    Cadillac Lowery New Member

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    Hello,
    I would pull the cap and check the rotor phase and rotational play. If it's not he phase My guess is it's about time for an overhaul on the mag or atleast replace the plastic square inside. My point is the mag may have some excess play causing a misfire as its wondering a bit much when you try to retard it and shut it off.
    Mine is ran directly out of the front of the cam and I have to service it often. Sometimes the shafts / keys and sometime the plastic square block (that's the best, cheap and simple). best of luck.
    Ps- I was unable to find my old pass word and have recently got a new email as the old got hacked.
    I've bought and sold a few things l, asked questions and replied to questions when I had some experience to offer although I'm a small tire turbo guy, lol.
    Great site, thanks!
     
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  4. jrracing

    jrracing Member

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    We run the 481x so base timing is 32 degrees if we pull more then 15 degrees out it will miss fire on a couple cylinders. We don't kill motor with the grid we use the mag switch with solenoid to shut the motor off, should we use the switch for the grid??
     
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  5. Top Drag

    Top Drag Wally Stelmach TD5560

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    This may sound dumb, but check your header gaskets. Sometimes a small leak will allow air in pipe and re-burn any fuel left. Very common in the old days on cars lifting throttle. Still see it today on roundy- round cars. Hope this helps.
     
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  6. Will Hanna

    Will Hanna We put the 'inside' in Top Alcohol
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    I have seen what you describe happen when someone wires a capacitor between the grid power switch and the grid. It would hiccup when you killed the switch, then run until the capacitor is drained.

    A kill solenoid is not necessary and is another potential component to fail with a grid. Killing power to the grid will kill the engine.
     
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  7. Mike Canter

    Mike Canter Top Dragster
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    Yes just shut power off to the Grid and keep it simple. Don't need special mag switches or solenoids. If you are running a MSD big red capa,capacitor only put it on the power wire and not on the switched wire for the Grid. If you put the cap on the switch power wire it will not shut off right away
     
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  8. hdanes4

    hdanes4 Member

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    When you kill power to the grid do you hook up the orange wire from the 4 pin connector or the 12 volt switched wire. And what amp switch do you use. Thanks for the help.
     
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  9. jrracing

    jrracing Member

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    Thats kind of weird you say that because #2 and #8 header flanges leak and that seams to be the 2 cylinders we are having issues with..
     
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  10. jrracing

    jrracing Member

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    We have no capacitors on the car but we do have a kill solenoid maybe we will eliminate that
     
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  11. Cadillac Lowery

    Cadillac Lowery New Member

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    In regard to the amount of timing you pull, I have a 44 amp with the big cap, small tire twin turbo Hemi and have pulled 24 degrees without an issue, normally its only 15-20 but as long as the rotor phase is correct it's fine.
    Good luck!
     
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  12. Jason Green

    Jason Green Member

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    Use the small (16-18ga) red wire and switch it on and off.
     
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  13. turbo69camaro

    turbo69camaro Member

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    With the big cap i run 32 base timing have mag phased @ 22 and pull 30 out on 2 step no cross fire issues ditch the mag kill solenoid it can caused its own set of issues
     
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  14. jrracing

    jrracing Member

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    Thanks for the advice the kill solenoid is going to be eliminated and we will see how things go.
     
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  15. Witchdoctor

    Witchdoctor Member

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    My question is if you remove the big red mag kill button and shut the car on/ off with the grid, when you go to start the car and spin it to build oil pressure and then pull the mag button on the car starts. If you only have the grid wont the car start right when you go to spin it over? I'd like to build some oil pressure before starting it.
     
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  16. Mike Canter

    Mike Canter Top Dragster
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    You turn the Grid on by a switch after you spin it over,,
     
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  17. Witchdoctor

    Witchdoctor Member

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    Ok thanks. I thought the grid had to boot up for a few seconds and flipping the grid switch to start the car may not be a good idea.
     
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  18. Mike Canter

    Mike Canter Top Dragster
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    I first thought that but it comes up in a preset mode that allows it to start while it is booting up. If you turn it on and watch the Amber/green LED it will first be yellow but the motor will still fire up and by the time it is running the LED turns to green. We start our cars that way with no problems.
     
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