Msd# 8973 help???

Discussion in 'PSI Superchargers Tech Questions' started by frank70, May 18, 2009.

  1. frank70

    frank70 NOSTALGIA DRAGSTER

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    :confused: I have just installed a MSD Pro Mag Controller #8973 on a blown alky motor with a 44 amp mag. I do not have a crank trigger on the car which MSD says is not a problem, it will work with or without, However i have no spark. I have checked at least 5 times all of the wires to make sure they go to the proper places. I have continuity on all wires and good ground's. The unit has power and will comunicate with the laptop. I have all the settings set on default as i just wanted to get the motor to light and run. Runs fine without the box but when I plug the box in I have no spark. Has anyone run across this problem before? Is anyone running one of theses boxes without a crank trigger? All I want to use the box for is a launch retard and nothing else, so all the other wires are not used. Should be very simple LOL!!!, But I am lost!!! Any info. would be great!!! Oh yeah, the box is new, just got it last week!!!
    :eek:
     
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  2. mbaker3

    mbaker3 New Member

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    Ask Will

    Ask Will Hanna, he really likes these 8973's and has become the one on here that can steer you in the right direction.

    Isn't that right, Will?:D:D
     
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    Last edited: May 19, 2009
  3. Will Hanna

    Will Hanna We put the 'inside' in Top Alcohol
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    8973 tech support

    Long story short, here's my advise: take it off. That box is a big pile of crap that kills motors and causes many headaches. Some will tell you it's the greatest thing since sliced bread. I highly recommend against it, along with some other well known top running alcohol racers that have had problems with. Marty Thacker, Larry Snyder and Ken Perry have all attributed blown motors to this box. They started hurting motors for no reason, disconnect the box, problem goes away. Use it if you must, but that's my .02.

    If timing managment is a must, get a six shooter set up.
     
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  4. Mike Canter

    Mike Canter Top Dragster
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    Frank. just ignore Will and his rants about the 8973. Everybody can figure them out but Will (lol).

    The first thing to do is to check the Data Editor and make sure that there is no Start Retard turned on. Make sure you have zero degree in the selection.

    Since you don't have a crank trigger then how have you wired up the 8973 to the ProMag. What color wires to what?
     
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  5. frank70

    frank70 NOSTALGIA DRAGSTER

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    When I called MSD they said to wire it this way:
    Red from Harness(#8164) to violet out of box
    Black from Harness to Green From box
    Clear from Harness to Bown/White From box
    On the mag side I have:
    Clear from Harness to Violet on mag
    Then instead of going to the crank trigger with the other wire 2 wires, you go into the other side of the mag with:
    Red from Harness to Orange/Black on Mag
    Black from Harness to Purple/Black on Mag
    Then Ground from Harness to Motor Plate

    I have the start retard function set at 0 degress. Everything else is set at default. Not running a Crank trigger makes this an even simpler system due to the fact I can not have anything out of phase, which is why im lost. Unplug the box and the thing lites right off!!! Would really like to make this work, really need to soften the leave on this car!!!
     
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  6. Mike Canter

    Mike Canter Top Dragster
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    With a laptop hooked up to the 8973 and the 8973 turned on lool in the upper left quadrant of the computer screen under Monitor and see if there are any faults. While you or somebody else watching the "Monitors" try and start the car and see if any faults show up.

    If nothing then pull the coil wire out of the rotor and put a sparkplug in the end of the coil wire. Lay it down on the metal part of the motor and then crank the motor and see if you get a spark on that plug.
     
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  7. frank70

    frank70 NOSTALGIA DRAGSTER

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    Thanks Mike i will give that shot and see what happens!!
     
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  8. Bob Kraemer

    Bob Kraemer New Member

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    Not that I know anything thing about the MSD 8973, but I have tinkered with electronic fuel injection software.
    Are you sure you saved your "changes" before proceding?
    Have you made a change "saved it", closed it out and gone back to make sure the changed was saved?
     
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  9. frank70

    frank70 NOSTALGIA DRAGSTER

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    Mike, I Tried to see if it would show any faults and it did not. Got ahold of MSD and they are going to send me another box. They seemed to think that since everything else works there must be a problem with it and I sure hope so LOL!! Thanks for the advice. Ill post again this weekend and let ya know if that worked!!
     
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  10. Mike Canter

    Mike Canter Top Dragster
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    If no errors showed up and it is wired correctly then it is probably bad. This is not the first one have run across that was received bad. It happens with the Digital 7 ignition boxes also. I wonder if they are all tested before they leave MSD.
     
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  11. Charles Terrell

    Charles Terrell New Member

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    mag harness is in backwards

    the mag harness is in backwards the ground end should be inside the car
     
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  12. frank70

    frank70 NOSTALGIA DRAGSTER

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    Charles, The way I have it is the way the instructions say to have it. I just read my original post to see if i typed it right and I did. Called MSD to verify, they say it is correct. Do you know somthing I dont? Msd is not always known to be correct so maybe you do. What wires are backwards? Also the grind from the mag cable is suppose to go to chassis ground, which I cant think of a beter place than the motor plate!! Are you running one without a crank trigger? Not saying your wrong but I am curious how you have yours hooked up!!!
     
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  13. frank70

    frank70 NOSTALGIA DRAGSTER

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    Mike, I hope your right. Ive been banging my head against the wall in the shop for 3 days trying to figure out what I done wrong!! MSD says they check all there boxs 4 times before shipping, however I have heard all kinds of stories about stuff being bad out of the box with theme. So if anything was wrong with the wiring it would be shown under the faults menu? Thanks for all the advice from everyone!!!!
     
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  14. Charles Terrell

    Charles Terrell New Member

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    Trust me I tune 5 different cars with this box. The end with the ground should be at the msd box. You can call me @ 434 203 1572
     
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  15. Mike Canter

    Mike Canter Top Dragster
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    Frank, the MSD diagram that comes with the 8973 shows the black ground cable end to be at the end that plugs into the 8973 as Charles states.

    I believe the wiring should be as follows

    The end of the 8164 harness with the black grounding wire goes towards the 8973

    Generator end
    Black/Red plug from Harness(#8164) to botton of the generator plug
    Clear wire plug from Harness to violet/green plug on generator (the upper plug)


    8973 End
    Clear wire plug from Harness to brn/wht plug on 8973
    Black/red plug on harness to green/violet plug on 8973

    Then Ground from Harness to Motor Plate or chassis

    Do you agree Charles or anyone else out there?
     
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  16. Charles Terrell

    Charles Terrell New Member

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    That's it Mike.I agree just looked at mine that's exactly how it is.
     
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  17. TWD

    TWD Blown alky

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    There may be two more things to check.
    I think the minimum advised starting speed is 200 rpm. We have an older unit that's fine at lower rpm, but maybe they built in some sort of safety to keep it from firing below 200 rpm in the mean time.
    If I'm correct you can also read the rpm from the laptop when cranking it over. If that reads ok, at least your trigger is connected the right way.

    HTH,
    Marcel
     
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  18. Mike Canter

    Mike Canter Top Dragster
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    There is no built in safety. The Mag generator just needs to turn fast enough to generate power. If this was the case then it would not start when used without the 8973.
     
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  19. nitro4100

    nitro4100 New Member

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    Charles check your PMs
     
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