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Engine shutting down over 5000rpm on higher boost

Discussion in 'EFI Tuning Questions and Engine Management' started by maca, Jul 24, 2017.

  1. maca

    Joined:
    May 9, 2016
    Hey all
    My combo. I am running a 360 magnum with a GT42 turbo on E85. I am using a MSD6al-2 programmable with a Billet MSD dizzy. For fuel I am running a Fitech throttle body injection.
    I tuned it on a dyno and apart from having to close up the plugs to .025 blowing the spark out it ran great. I ended up with a low boost setting of 430hp @ 8psi and a high boost setting of 620hp @ 15psi

    At the drags on low boost its fine but on high boost it gets to just over 5000rpm and it feels like the engine completely shuts down and then comes back and revs to 6500rpm when I change gear.
    Then its fine. It only does it in 1st. 2nd and 3rd are fine and it revs clean to 6500rpm. When it does it, it drops from around 55300rpm to around 4300rpm before it comes alive.
    I have data logged the fuel and its fine and doesn't lean out.
    Any suggestion?
     
    Last edited: Jul 24, 2017
    maca, Jul 24, 2017
    #1

  2. Forcefed86

    Joined:
    Nov 24, 2005
    Try .019 gaps and see if it improves.
     
    Forcefed86, Jul 25, 2017
    #2

  3. maca

    Joined:
    May 9, 2016
    I will give it a shot but its more like total engine shut down for a fraction of a second. I would expect if the spark shut down it would be like hitting the limiter and when it fires back up I would get the poping and flames out the exhaust.
    But I will give it a go.
     
    maca, Jul 25, 2017
    #3

  4. blown385

    Joined:
    Feb 17, 2007
    Could something be triggering a two step ?


    Is the two step set in the 4300 area ?

    Example ........ if your at 6000rpm and you trigger a 4300rpm limiter , the engine will not fire again until 4300rpm .
     
    blown385, Jul 25, 2017
    #4

  5. maca

    Joined:
    May 9, 2016
    Not sure if the msd has a 2 step setting but i will find out. After it comes alive again it then revs cleanly to 6500rpm.
     
    maca, Jul 25, 2017
    #5
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