?? For seasoned tuners (re; hesitation)

Discussion in 'Mazdaspeed 3/6 ECU Tuning' started by VoodooJef, Jan 27, 2018.

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  1. VoodooJef

    VoodooJef My friends call me Captain Zen Greenie Member

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    I`ll forego the qualifiers. We are adults here.

    Self tuned w/ VT and the car runs really great, makes tons of power, and has so far been reliable as I could have asked since built motor. One odd thing it does, and I can`t recall when it started, is it seems to stutter or hesitate if I just mat it. Not a misfire type situation at all, rather it starts to accelerate, hesitates, then rips my face off like it`s supposed to. Almost feels like it`s caught in the CL/OL transition. Nothing particularly noteworthy in the logs. The tune isn`t specifically aggressive as far as timing goes. It seems to only do it at lower engine speeds (lower being 2500-3K)...if I floor it at 4K in 4th, for instance, it just hauls ass but if I`m in 2nd or 3rd and I`m scooting away from a stop sign it`ll do it.

    I`ll dig into it once the weather warms up and eventually figure it out but anyone have any ideas to cut my troubleshooting time down?
     
  2. Trithemius

    Trithemius Expert N00b Silver Member

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    This sounds exactly like a symptom I used to have. Do you have a check engine light involving cam/crank position correlation, or timing over or under retarded? My issue turned out to be an improperly timed intake cam, just a few degrees off. It ran great up top, but if I entered boost at 3000 rpm, it would bog and pull ignition timing back until 3700ish and then pull hard. Retimed just the cams, and all was good. Maybe timing slipped a touch? I'm just going off what I've personally experienced. Those friction washers are kind of scary to think about.
     
  3. VTMongoose

    VTMongoose John/MD1032 Platinum Member

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    More details are needed. "Nothing noteworthy in logs" - The type of activity you are referring to would surely be visible in logs. You should log the behavior with the following parameters and report back:

    APP
    Calculated Load
    IAT
    BAT
    Vehicle speed
    MAF Volts
    Boost pressure
    Throttle position
    Actual AFR
    Engine RPM
    HPFP Actual pressure
    IDC
    WGDC
    KR
    Intake valve advance
    Spark advance

    Please also post the following details:
    - Year and model of car
    - Disposition of any SWAS defeat measures in place
    - Air bypass valve make/model
    - Turbo make/model and compressor housing used if it's a Garrett or precision unit

    This is as likely to be a hardware problem as a software problem.
     
  4. VoodooJef

    VoodooJef My friends call me Captain Zen Greenie Member

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    no CEL at all, all good there. Not saying it couldn`t be, just no evidence.

    Also, it very well may be SWAS influenced. It seems to only do it if I have SWAS enabled (though not enough digging at this point to see a true consistency), and the car has shown previously to be very sensitive to swas input.
     
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  5. Littleloogy

    Littleloogy Recovering Speed Addict Platinum Member

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    My car is doing the same thing thing. I am thinking it is in my gear 1&2 load tables. It behaves just like SWAS, but I was under the impression VT disabled those characteristics if you checked the box. Almost feels like the car is hitting high load and the ECU is doing everything it can to reduce it.


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    Littleloogy, via a mobile device, Jan 28, 2018
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  6. VoodooJef

    VoodooJef My friends call me Captain Zen Greenie Member

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    I can say from true tested experience that even VT doesn`t completely disable SWAS. Steve has gone on record saying they (as well as everyone else tuning the platform) didn`t want the responsibility of disabling a factory safety feature. Once I hit about 400ft/lbs swas was a constant nuisance, and with it disabled in VT it came back around 425ish ft/lbs. I do have a switch wired in for it but it`s blatant when I forget to turn it off if I`m getting on it hard.
     
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  7. Littleloogy

    Littleloogy Recovering Speed Addict Platinum Member

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    Damnit. I can understand as to why VT would be hesitant. I guess I will be making a cool “Go Baby Go” switch. Thank you for the good info @VoodooJef hope this fixes my issue.

    Regarding your issue, have you been able to confirm that SWAS was the cause in your case?


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    Littleloogy, via a mobile device, Jan 29, 2018
    #7
  8. VoodooJef

    VoodooJef My friends call me Captain Zen Greenie Member

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    No, I haven`t gotten to A/B for these symptoms yet. I can tell you definitively that swas interferes and what to look for, just haven`t gotten to log these particular symptoms yet. I am 100% sure that at least in my case it`s not a load cap thing. Maybe I`ll take the long way to work today and see if I can catch it in a log.
     
  9. VoodooJef

    VoodooJef My friends call me Captain Zen Greenie Member

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    70 degrees out today and no hesitating. I`m guessing there is a load table that`s set close to its headroom limit being affected by the cold weather.
     
  10. SharksInSpace

    SharksInSpace Planets and shit. Silver Member

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    give me your weather.
     
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  11. VoodooJef

    VoodooJef My friends call me Captain Zen Greenie Member

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    it`s a fluke. Not that we`re still frigid cold or anything but we`re low 50`s during the day. Probably still warmer than where you are.

    #effthecold
     
  12. Littleloogy

    Littleloogy Recovering Speed Addict Platinum Member

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    Agreed. We hit high 60’s today. California Politics suck ass, but the temps are kickass!


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    Littleloogy, via a mobile device, Feb 1, 2018
    #12
  13. rfinkle2

    rfinkle2 Greenie Member

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    Post a log when you get a chance.
     
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  14. VoodooJef

    VoodooJef My friends call me Captain Zen Greenie Member

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    Hasn`t been cold enough to make it happen again to get a log of it.
     
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