crank trigger pickup problems

Discussion in 'PSI Superchargers Tech Questions' started by jody stroud, Nov 26, 2011.

  1. jody stroud

    jody stroud ZOMBIE Top Dragster

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    Have any of you guys had trouble with mutiple bad crank trigger pickups. Tried Leahy, Spud Miller, and now I'm on a MSD. Is there some secret that I don't know?
     
    #1
    jody stroud, Nov 26, 2011
  2. Mike Canter

    Mike Canter Top Dragster
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    That's funny Jody because if I remember correctly you have bragged on how Greta the Leant and the Spud ones are. Seriously the odds that you lose all three due to defective sensors is pretty slim. One thing that can wipe them out is the degree wheel making contact with the sensor due yo crankshaft flex. Look at the working end of all the sensors with a lighted magnifying light for any evidence of contact. One hit at high rpm will kill it. I have always placed the sensors in to nine o'clock or three o'clock position to minimize contact from flexing. Also I run the sensor out at Max gap to minimize contact. Have you tested all the sensors with a ohm meter and if so how many ohms do all read. If the resistance is good on all sensors then the only other thingvis that the magnets in the degree wheel are weak do a comparative test on all the magnets with a small screwdriver tip and service they all have the same amount of pull. If that degree wheel is off center can cause problems. Rotate the motor and check the airgap at all magnet positions and see if they are all the same. I know you have my cell number so call me with all you find out.
     
    #2
    Mike Canter, Nov 27, 2011
  3. Andy C

    Andy C Member

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    wiring

    I had a simular problem... changed the wire to the pick up... problem went away.
     
    #3
    Andy C, Nov 27, 2011
  4. texas racer

    texas racer New Member

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    i agree, sounds like at some-point, the wheel contacts the pickup..
    rotate the motor by hand and check it air gap on the 4 magnets .
     
    #4
    texas racer, Nov 28, 2011
  5. jody stroud

    jody stroud ZOMBIE Top Dragster

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    Yeah, thanks guy's...I'll check the clearance. Should be good though, I run appox.050. And I didn't see any contact marks on the pickup or degree ring. Can you damage one by overtighting the clamp? I sometimes...in an effort to insure steadfastness tend to over-tighten things.
     
    #5
    jody stroud, Nov 28, 2011
  6. Mike Canter

    Mike Canter Top Dragster
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    Jody, do me a favor...get hold of an ohm meter and check the resistance across all those crank trigger sensors including any know good ones. They should read 65 to 85 ohms if they are good. That will tell us alot.
     
    #6
    Mike Canter, Nov 29, 2011
  7. Frank Kramer

    Frank Kramer New Member

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    I'm running my Leahy crank triggers at 3 o'clock with .085 gap.

    Frank
     
    #7
    Frank Kramer, Dec 1, 2011
  8. summitcb

    summitcb Member

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    I run a MSD mag 20, MSD small crank trigger pick up.

    At .085 gap would not fire, change to .050 and fires right up, also battery needs to charged up to spin motor over fast enough to light the mag and thats with a 16v battery.

    Does the Mag 44 fire easier than a 20.

    Steve
     
    #8
    summitcb, Dec 1, 2011
  9. jody stroud

    jody stroud ZOMBIE Top Dragster

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    Always cranks fine..with 16 volts and block mounted starter with a mag 44. My car just popped and quit in the waterbox. Then ..back at the pits it cranked with the ingnition OFF (I run a Power Grid) and shut down when I flipped the power on. Changed pickups and everything went back to ..My.. normal.
     
    #9
    jody stroud, Dec 1, 2011
  10. summitcb

    summitcb Member

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    I had a different issue this season, which I thought was a bad crank trigger. Was testing transbrake switch and back up switch. Shut the car off, had laptop still conected to the Power Grid 7730 box. Tried to restart and couldn't figure out why motor would fire but not run. Turns out the safety rpm setting was tripped and since it was set to 1200 rpm motor would not run. I had shut the power off to the ignition system but with the laptop connected the power grid controller is still on and did not reset. Disconected 7730 from laptop, cycled the power to the car removing the saftey rpm controller and everything worked again. To say I had a few confusing minutes would be an understatement, with out the excellent monitoring software that comes with the 7730 I may never have figured it out. Of course in the between time I changed the crank trigger pick-up, tried firing off the mag and started pulling out what little hair I have left.

    The safety setting on this box should almost become manditory for any fast car, lost a friend this year and if he had it in his car he may still be here. He passed out after the launch and shift and never lifted hitting the trees at over 200 mph. This safety feature would have idled the motor shortly after the end of the run and the crash would have been well under 100 mph. Might have or might not have made the differance, never going to know.

    Steve
     
    #10
    summitcb, Dec 1, 2011
  11. Blownalky

    Blownalky Top Sportsman

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    Agree on that safety feature, best little "Value Added" item I have seen in years.
     
    #11
    Blownalky, Dec 2, 2011

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