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Thread: Transient Tuning

  1. #1
    Tuner Blown383's Avatar
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    Transient Tuning

    Does anyone have any pointers on tuning transient fuel on Mustangs? I've got a serious lean tip-in issue when the engine is cold that I have been fighting with for a while. I have managed to tune out my lean tip-in when the engine is hot. Throttle is crisp and responsive only if the motor is hot. This goes hand-in-hand with rich tip-out. I've tried adding to the startup tables but it doesn't seem to help. I also can't figure out if all of the decel stuff needs to be increased or decreased to reduce tip-out fuel. I believe I have a grasp of x-tau transient fueling theory but I'm still scratching my head. All mods are in sig. Any pointers are appreciated.
    2007 Ford Mustang GT/CS: RGR 322 3v - JPC Intake - Vortech YSi-B - Magnum T56 XL - Built 8.8 - Full Suspension
    2008 Ford Shelby GT500: VMP Gen 2 - ATI 15% - SCJ TB - Full Bassani Exhaust - Full Suspension - Upper Pulley - Meth Injection - JLT 127mm

  2. #2
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    Best bet is to post a log and the tune. Ill gladly take a look.. Guessing you are blowing through that HPX MAF, what size tube is it in?

  3. #3
    Tuner Blown383's Avatar
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    Want me to post a log with SCT or an HPTuners log? What parameters? It's a 75mm VMP housing in blow-through.
    2007 Ford Mustang GT/CS: RGR 322 3v - JPC Intake - Vortech YSi-B - Magnum T56 XL - Built 8.8 - Full Suspension
    2008 Ford Shelby GT500: VMP Gen 2 - ATI 15% - SCJ TB - Full Bassani Exhaust - Full Suspension - Upper Pulley - Meth Injection - JLT 127mm

  4. #4
    I have similar problem with 47lb injectors, I guess they have different spray pattern and fuel is trapped on the walls.
    Only on cold engine.

    http://www.hptuners.com/forum/showth...spot-when-cold

    Transient fuel tables are added last time to 3v calibrations, but haven't played with them yet.

    Can someone explain how they work?

    Gain at startup and time at startup has only functions of ECT, so looks one of this table should be modified.
    Eastern and Central Europe American Muscle and Harley-Davidson tuning
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  5. #5
    I tested transient also. Its not possible to get rid of rich spot at throttle off, even with manifold volume 30 and all decel tables zeroed.
    As i could tune quite good accel, no way with decel. Maybe in this table could be negative values it would work. i gave to test it on another car, this that i test now has 60lb and this are slow, so maybe pulse width...
    Last edited by caniggia; 12-04-2014 at 02:03 PM.
    Eastern and Central Europe American Muscle and Harley-Davidson tuning
    www.hd-customs.pl
    http://www.facebook.com/hdcustomspl

  6. #6
    In this situation i deleted decel tables and lowered min pulse to even 0.8 and got rich decel for only 0.2-0.4 sec to 13.5 from 10. Lowered intake manifold to 7 and multiply accel gain by 2.0 and time for 1.2.
    Got perfect running car, but on afr i see lean spot on quick accel for about 0.2 sec to afr 15-16 and then normal to 12-13, tomorrow i check cold, should be ok, today morning was better with some first adjustments.

    Btw, this siemens 60lb are rated to min pulse 1.3. In injector data i wrote they have better idle with 1ms limit, 0.8 seems even better.
    I dont know who is preparing this data at factory...

    This is on turbo car, this one was not that bad as second cammed turbo with 47lb that i'll try next.
    Eastern and Central Europe American Muscle and Harley-Davidson tuning
    www.hd-customs.pl
    http://www.facebook.com/hdcustomspl

  7. #7
    I tested this car finally and also another turbo with 47lb partially today.
    60lb rich decel was fixed by min pulse (this injectors I'll change and never use again), lean spot fixed best bu adjusting manifold to 5l and DELETE accel gain table (that's strange, I know). After this fuel trims got totally crazy, so I had to bring this table back and lower values, so it's not really perfect, but acceptable. Maybe it's also problem of 60lb as they get very short impulse at tip in.

    47lb is working great now also cold after only adjusting manifold to 6l.

    I don't get how transient fuel tables works and looks they have nothing to do on tip in.
    Eastern and Central Europe American Muscle and Harley-Davidson tuning
    www.hd-customs.pl
    http://www.facebook.com/hdcustomspl

  8. #8
    lean tip-in, rich tip-out is usually cured by dialing in the load w/failed maf table. if you cant log the proper , you can usually add 20% to the table till its gone.

    I log load, tp relative, rpm and go for a drive around town and try and hit all the rpm and load under various tp.

  9. #9
    load with failed maf is completly not working in any mustang calibration I tested. You can make there 0 and max 1.99 and it has no difference in anything, even if maf is disconnected, I wrote another topic about that. Anyway, I have then dialed in.
    Eastern and Central Europe American Muscle and Harley-Davidson tuning
    www.hd-customs.pl
    http://www.facebook.com/hdcustomspl

  10. #10
    I read your write up and the lwfm does not work that way. Its not actually speed density. Lwfm is used in all 3v calibrations and is used during throttle transitions when the maf cant respond fast enough.

    once your maf and injector data is 100% correct, then lwfm works properly.

  11. #11
    I always have them dialed in anyway, so i dont look there for the problem.
    If its like you say, i still belive there is hidden speed density table... But its not topic about.

    Now i'm courious how transient tables are working.
    Eastern and Central Europe American Muscle and Harley-Davidson tuning
    www.hd-customs.pl
    http://www.facebook.com/hdcustomspl

  12. #12
    Proper tuned car when drives without maf makes car always 20% rich at low load and 20 at high, maybe this is the problem...

    Facts for now:
    Manifold volume changes how fast pcm reacts on quick throttle change and this is correct, smaller manifold should react faster.
    So low values makes fast enrichment and richer mixture, higher oppostite.

    Transient fuel works in normal driving, looks also in steady state, i havent seen any change how fast reaction is in tip in or out even zeroing and maxing tables, but after pcm reacts, maxed tables caused that car was flooded even at start without touching throttle, once started, was unable to drive.

    Slow injectors are causing rich decel and some problems on tip in also, because pcm directs very short pulses before normal pulse or sometimes short are between normal, i checked this today with oscilloscope.
    Last edited by caniggia; 12-06-2014 at 01:12 PM.
    Eastern and Central Europe American Muscle and Harley-Davidson tuning
    www.hd-customs.pl
    http://www.facebook.com/hdcustomspl

  13. #13
    Advanced Tuner f.creek-ranch's Avatar
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    older but...
    I have the same problem with eforce on 4.6. lean tip in in cl and rich tip out. 41lbs injectors.
    LWFM only works, if anticipation is set active.
    try to figure it out....
    watch for fuel pressure....
    Last edited by f.creek-ranch; 10-20-2019 at 04:29 PM.

  14. #14
    Advanced Tuner f.creek-ranch's Avatar
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    got the problem.....

    stock pump set from 269 kpa to 300 at low load.

    Higher the voltage, max flow and multiplicator for the pump.....no more lean tip in and good transient .

  15. #15
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    Did you correct the ISC Drive/Neutral Idle Air functions and correct the Airflow Multiplier Drive/Neutral tables? Those four things are usually the biggest cold start issues assuming your MAF and injector data is correct. Also ensure your lowest spark value isn't' limiting you on corrections.

  16. #16
    Advanced Tuner f.creek-ranch's Avatar
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    Cold start is a problem by o2?s or response.

    Now I have set O2 activation to 650? C and timing for it to 320 sec. I have disabled O2 heaters and change fuel base cold table.

    Closed Loop is now enabled at 4 minutes at 5? C. This helps a lot by leanout at cold start.

    The main problem is actual the lean light tip in in closed loop.

    I will try it with much more transient and the timing for it, but I think ist a dead table.

    tip out is even strange....getting very rich....

    set deceleration fuel cut off , disabled load to 0,4 and hope the cut off will fix it.
    Last edited by f.creek-ranch; 11-16-2019 at 11:13 AM.

  17. #17
    Tuner in Training
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    Sorry to bother guys but I have a Mu52 injectors on a 4.6 3v and I’m having the exact same issue on cold starts. When the engine is cold it has lean spots with throttle input. But once the motor is warm the lean spots disappear . Have you guys figured this issue out ?

  18. #18
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    It's not transient that you need to address. Transient accounts for fuel that is stuck to the runner walls.

    Chances are good you need to adjust your Load With Failed MAF (LWFM). Read this thread, see if you can get anywhere: https://forum.hptuners.com/showthrea...mp-WOT-Surging