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Ignition Cut for No Lift Shifting

Discussion in 'FAST Support Forum' started by fabr, Feb 10, 2017.

  1. fabr

    fabr Member

    Joined:
    Jan 23, 2017
    Is there a way to cut fuel using a load cell signal to the ecu to allow no lift up shifting? Additionally can I also control a throttle blip solenoid using a load cell signal to the ecm for a down shift with the sportsman?
     
  2. Fastmanefi

    Fastmanefi Member

    Joined:
    Jun 4, 2011
    Location:
    Sonora, CA
    You probably want an ignition cut rather than fuel cut because it's much faster. The XFI 2.X can produce the required signal as a digital output but the Sportsman cannot. You can cut fuel too with the addition of a solid state relay.
     
    Last edited: Feb 11, 2017
    fabr likes this.
  3. fabr

    fabr Member

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    Jan 23, 2017
    Thanks!
     
  4. fabr

    fabr Member

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    Jan 23, 2017
    Will the xfi 2x also provide a signal to the throttle solenoid to blip the throttle for downshift?
     
  5. Fastmanefi

    Fastmanefi Member

    Joined:
    Jun 4, 2011
    Location:
    Sonora, CA
    There is no throttle solenoid unless you add it.
     
  6. fabr

    fabr Member

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    Jan 23, 2017
    Yes,I understand that. Thanks.
     
  7. fabr

    fabr Member

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    Jan 23, 2017
    OK,I'm using an MSD HVC-L ignition and I can do an ignition cut for flatshifting using the ignition disable circuit it has as per MSD. Doing so would also kill the tach signal for the duration of the shift which would be in the 50-75 milliseconds range. My question now is would that possibly cause issues with the EZ or sportsman ecu's or issues with confusing the ecu after the MSD rpm output signal is restored? I would not be cutting power to the EZ or Sportsman ,just the tach signal would be lost momentarily.
     
    Last edited: Mar 7, 2017
  8. Fastmanefi

    Fastmanefi Member

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    Jun 4, 2011
    Location:
    Sonora, CA
    I never tried it, but I think it would work because all the ECU does is stop without an RPM signal.
     
  9. A A

    A A Well-Known Member

    Joined:
    Jun 22, 2014
    It won't affect anything even if the ECU is controlling timing, unless you are using an RPM module on the coil - which you shouldn't be using a coil RPM module anyway. Richard is correct.:)
     
  10. fabr

    fabr Member

    Joined:
    Jan 23, 2017
    Thanks for the reply but would you clarify what you mean by the ECU stops when it loses rpm signal.Do you mean that it would shut down all injection functions and instantly restart upon the rpm signal being reintroduced which would be very beneficial or would it take time to restart injection or the ECM which would not suit my needs?
     
  11. Fastmanefi

    Fastmanefi Member

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    Jun 4, 2011
    Location:
    Sonora, CA
    Yep. The ECU is running at full speed and doesn't stop. The injection and timing output just wait for the crank signal to start up.
     
  12. fabr

    fabr Member

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    Jan 23, 2017
    Great! Thanks very much!! Ummm,you did mean rpm signal didn't you instead of crank (trigger) signal?
     
  13. Fastmanefi

    Fastmanefi Member

    Joined:
    Jun 4, 2011
    Location:
    Sonora, CA
    If its a Sportsman or XFI (which you mentioned above) I assumed you were using it for the timing control. But if its an EZ I would wonder why run an EZ on a race motor since idle control becomes and issue with a radical cam and a totally self learning EZ.
     
  14. fabr

    fabr Member

    Joined:
    Jan 23, 2017
    I have the EZ now,didn't know of the possible idle issue with low vacumn (I have 6 inches at idle but almost immediately upon cracking throttle I have 10 inches)when I bought it since FAST fails to tell a person about that but honestly,I am seeing no idle issue at all at this time anyway. I can and will step up to a sportsman if I begin to encounter problems but in the meantime I can achieve my goal of minimizing dog ring wear in my very expensive Fortin sequential transaxle utilizing a Geartronics Easyshift ECU controlling ignition cut of the MSD HVC-L ignition. The only downside to that is the momentary loss of tach signal from MSD to FAST EZ which will actually be a benefit since the fuel will also be cut during the shift.

    I do understand the greater flexibility/tunability of the sportsman and I may well have to step up to it but for now I can accomplish my goals and if/when I step up to a sportsman I can still use the same Geartronics setup without any wiring mods whatsoever.

    That said,would anyone give me a nice trade in deal on my EZ for a sportsman? It's got less than 2 hours run time.LOL!!
     
    Last edited: Mar 8, 2017
  15. Fastmanefi

    Fastmanefi Member

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    Jun 4, 2011
    Location:
    Sonora, CA
    I have done several EZ to Sportsman swaps. FAST helps out with this swap because they want happy customers.
     
  16. fabr

    fabr Member

    Joined:
    Jan 23, 2017
    Would you pm me with what you/we could do?
     
  17. Fastmanefi

    Fastmanefi Member

    Joined:
    Jun 4, 2011
    Location:
    Sonora, CA
    Please call me and we can discuss the details. My phone is on my website.
     
  18. fabr

    fabr Member

    Joined:
    Jan 23, 2017
    Will do. Might be next week sometime. Thank you.
     

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