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Thread: FMEM Limits Overboost or Underboost?

  1. #1
    Tuner in Training
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    FMEM Limits Overboost or Underboost?

    Hey guys,

    I keep getting the turbo FMEM and turbo 2 FMEM limits, and I can't seem to figure out why. From what I've read it's either an over or underboost condition, but I'm not sure what parameters I'm supposed to be looking at for desired vs actual, nor what tables actually control this.

    2018 3.5L F150.

    Running the EFR Full Race turbo setup, larger FMIC, Exhaust.

    This setup uses pneumatic WG instead of the electronic ones, so I know I'm loosing some control in that realm, but I'm hoping I can just get rid of the underboost error completely and raise the overboost up to a static limit (not changing with RPM/Flow)? Or what's the best solution around this to keep the throttle open all the way to redline?

    Right now I'm only seeing' ~17-19psiG (~12-14psiA since we're at elevation).

    I'm not sure what to look at in the log, nor what tables to manipulate. I thought I completely eliminated the FMEM in the airflow limit switches, but that doesn't seem to work.

    Any help would be greatly appreciated.
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  2. #2
    Advanced Tuner LastPlace's Avatar
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    If you have removed the ecm's control of the turbo chargers, why not start by removing any limits that control those functions.

    If I remember correctly, that is pretty much the approach the tuning school uses for ecoboost.
    Last edited by LastPlace; 09-11-2019 at 02:53 PM.

  3. #3
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    I would love to, and i thought removing the airflow limits for fmem, injector, popcorn, ect would eliminate them, but that didnt work. So im not sire how to kill then off? What still has control over them?

  4. #4
    Advanced Tuner LastPlace's Avatar
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    If I remember right, they max all the limiters out and "tune" (screw up) the throttle body modeling to remove the throttle body's ability to close (controlling boost).

    Seems like their method would work for your project.

  5. #5
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    Right.....that sounds completely good and well in theory.....but what are the actual tables I need to modify? (Like the table numbers so I don't screw this up).

  6. #6
    Advanced Tuner LastPlace's Avatar
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    Quote Originally Posted by CK@UPP View Post
    Right.....that sounds completely good and well in theory.....but what are the actual tables I need to modify? (Like the table numbers so I don't screw this up).
    https://thetuningschool.com/collecti...-ford-ecobbost