no spark 7531

Discussion in 'PSI Superchargers Tech Questions' started by big wheel, Oct 18, 2009.

  1. big wheel

    big wheel New Member

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    any ideas on a no spark when you hook up crank trigger on 44 msd 7531 with a lehey on one side and a msd trigger on the other ? neither will spark on crank triggers. have run for 3 years. magnets seem to have a strong pull and both have been ohm out.110 on msd 47 on lehey. batterys on both starter packs full charged. crank speed? 125 psi ....suggestions about to burn,have had problems in past..thngs un plugged out of phase low crank speed .i have set pick ups wide and close. any takers
     
    #1
    big wheel, Oct 18, 2009
  2. Mike Canter

    Mike Canter Top Dragster
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    Do you have any Start Retard added in the 7531? It will not work with Start Retard. Make sure it is zero'd out. Also that rotor has to be pretty close on static phasing for it to work. So if you set the degree wheel on what ever timing such as 26* then the crank trigger magnet better be right across from the middle of the pickup and the rotor better be right at number one terrminal on the cap. If that is all good then take all the plugs out so the motor spins faster on the starter and spin it like that and see if you get spark then. If you get spark with no plugs in the car then it is a problem with the cranking speed being too low. If you are using a 12 volt starter with a 12 volt battery then you either need to switch to a 16v or a 24 v battery to get cranking speed or get a bypass switch from Leahy or MSD and start it on the mag then flip the switch to put it on the crank trigger.
     
    #2
    Mike Canter, Oct 18, 2009
  3. Danny Humphreys

    Danny Humphreys Member

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    I had a similar problem, the spark is incredibly weak for some reason with the 7531 w/ leahy pickup. i couldn't see it. Turned all the lights off and could barely see it. threw a little gas in and it fired right up, have you tried starting it? If it still won't start, start it on the mag (bypassing the 7531 andf crank trigger by plugging the top of the mag into the bottom) to make sure it's not some other issue.
     
    #3
    Danny Humphreys, Oct 18, 2009
  4. big wheel

    big wheel New Member

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    well took the day off.mike this is bennie. 48 volt starter.but had all plugs in engine except no 1, new engine . spun rear main at rock. trying to go to texas next week , it would not spark at dragstock 1st qual but we tharshed and it would off mag not crank trigger. then it started no problem found. guess tommorow try moving trigger while cranking to see if that will help it has in the past, i added another trigger a lehey .msd had on for years to have a back up...this system is good but it will give you headache every now and then..will agrees
     
    #4
    big wheel, Oct 18, 2009
  5. Mike Canter

    Mike Canter Top Dragster
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    Hey Bennie. Well if it has run with this setup and runs off the mag and not the crank trigger and you have tried two crank triggers then it pretty well leaves to the air gap or the phasing. Try a gap of .080. Have you tried the plug in the end of the coil wire yet. If you get spark doing that but not out of the end of a plug wire then it is a rotor phasing problem which can be caused by the trigger not being positioned correctly.
     
    #5
    Mike Canter, Oct 19, 2009
  6. big wheel

    big wheel New Member

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    well if all fails give up and go to state fair. mike the flaming river give me the fits. just like the pilot that was tapping on the gauge and made a land dart landing. bad timing light.guess i go to texas! thanks mike
     
    #6
    big wheel, Oct 19, 2009

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