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Thread: Part throttle stutter Mustang

  1. #1
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    Part throttle stutter Mustang

    2017 mustang 3.7 mu52 injectors e85.

    At partial throttle in any gear above 1 around 2-3k i get a shutter / stumble. this happens even with the stock tune with only injector information weather im e85 or running 93. i have attempted to adjust DD tables. i have turned of the shuffle switch. i have changed best drive ability minimal load to 5. my LTFT look decent and my STFT arn't outrageous when its happening. i dont see any detected misfires but i see a lot of throttle position fluctuation. pedal ~30% throttle position at 90 then drops then picks back up. i have cleaned the throttle body to be safe it doesn't stick and if your above 3k it doesn't do it no matter where the pedal is. I do notice that when issue is happening i seem to be using tables mp9 and 14 and fuel economy drive is the vct source. any tips on maybe disabling it?

    any help is greatly appreciated. i am trying to fix drive ability issues before trying to go all out.
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    Last edited by Mercilus; 4 Days Ago at 08:27 PM.

  2. #2
    Advanced Tuner veeefour's Avatar
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    I think you might have a wrong injector data.

  3. #3
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    Best place to get injector data for those injectors is a stock 13-14 GT500 file. The inferred rail pressures go to a higher fuel flow as well.

    MAP based car, its all dependant on SD for MAF value and fuel injector/ pressure data.
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    "We can never be right, we can only be sure that we are wrong"- feynman

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    Quote Originally Posted by murfie View Post
    Best place to get injector data for those injectors is a stock 13-14 GT500 file. The inferred rail pressures go to a higher fuel flow as well.

    MAP based car, its all dependant on SD for MAF value and fuel injector/ pressure data.
    Ok i will try this. I was using fords data from their site.

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    The injector data isn't 100% correct comparing it to the GT500 files I have. The reason you're getting the oscillation is because of your spark tables.
    Your spark tables would be easier to go through if the RPMs were the same so you won't have to use a calculator to get your values. If you have 3500 and 4000 on borderline, and 3750 on MBT, you'd have to calculate to get where borderline is at for 3750 RPM. I would copy Borderlines RPM axis on to MBT axis, then compare it to your previous file and move your MBT columns to where they need to be. If 4000 moved over one column move the column values over.

    As load increases, timing on both borderline and MBT should decrease.

    At the same time as oscillation, timing is being removed to prevent knock because your borderline is too advanced and that's also why your spark source will occasionally go into torque control.
    Borderline should be less advanced than MBT beginning around .30 load. On your datalogs, I seen this happening more in 5 and 9, so I checked the tables on your file. You need to check all your tables for this because this is just parts of what needs changed on these three tables.. The blue needs to be re-arranged so timing decends as load increases. The red is too advanced.
    check spark.png

    This torque source should not be going into oscillation if you had the switch disabled.

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    You're also getting torque control at idle because your have driver demand way to high. This car will never idle at 45 ft lbs.
    All of your driver demand needs to be adjust. You want to have a somewhat realistic number, and a little higher than engine brake torque. Some of your other gears have 1000 ft lbs in them.

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    Ok i will work on this. I wanst sure if changing the factory tables would be safe.also when the ocillation occurs its constantly adding timing iant it? If you look at -4 on the scale in the table its ahowing as adding 4 degrees.

    Maybe im looking at it wrong? Thank you for being patient with me as im still learning what all is changeable. This is also why the vct tables throw me off but the 5.0 vct tables make perfect sense.

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    Quote Originally Posted by Thatwhite5.0 View Post
    You're also getting torque control at idle because your have driver demand way to high. This car will never idle at 45 ft lbs.
    All of your driver demand needs to be adjust. You want to have a somewhat realistic number, and a little higher than engine brake torque. Some of your other gears have 1000 ft lbs in them.
    Thatwhite5.0 that is how it comes factory.

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    Running E85 you have much more octane. Octane is the determining factor of where the MBT and borderline should cross. The fact you are getting knock while using e85 and still NA, its most likely false.
    The knock logic usually enables around .35 load. As that's usually when there's enough air in the cylinder, that the energy produced from the knock can cause damage. Having borderline drop below MBT here is usually being overly cautious, or you are planning on running 87 octane. Setting up like that the knock advance would start to advance right away and you probably wouldn't leave the MBT value until a higher load, or if the advanced was limited too much to maintain MBT.

    The other factor is just the general design of the combustion chamber.
    Borderlines going to be a very dynamic thing, not dependant flat on load or rpm. That's why you want your knock sensors to figure it out for you. Detonation is the dynamic phenomenon, MBT only changes slightly when you are using different fuels and targeting different lambdas.
    You don't want to go too aggressive with the borderline tables, but you don't want to be too soft either other wise the knock sensors have too much work to make up. All the correction tables for borderline are to help spark be closer to where the knock sensors may see detonation.
    If you are at MBT, that's the best you are going to get, going more or less is just going to get less torque.

    So apply white5.0s logic of timing descends as load increases to the MBT tables, with a slight increase as RPM climbs and put the borderline tables just slightly less than where you are picking up knock with your knock sensors, after verifying you are not getting false knock. Detonation at less than MBT is what you are looking for. If you are at MBT, the knock sensors well still reduce timing if they sense knock, putting you into "borderline."

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    Quote Originally Posted by murfie View Post
    Running E85 you have much more octane. Octane is the determining factor of where the MBT and borderline should cross. The fact you are getting knock while using e85 and still NA, its most likely false.
    The knock logic usually enables around .35 load. As that's usually when there's enough air in the cylinder, that the energy produced from the knock can cause damage. Having borderline drop below MBT here is usually being overly cautious, or you are planning on running 87 octane. Setting up like that the knock advance would start to advance right away and you probably wouldn't leave the MBT value until a higher load, or if the advanced was limited too much to maintain MBT.

    The other factor is just the general design of the combustion chamber.
    Borderlines going to be a very dynamic thing, not dependant flat on load or rpm. That's why you want your knock sensors to figure it out for you. Detonation is the dynamic phenomenon, MBT only changes slightly when you are using different fuels and targeting different lambdas.
    You don't want to go too aggressive with the borderline tables, but you don't want to be too soft either other wise the knock sensors have too much work to make up. All the correction tables for borderline are to help spark be closer to where the knock sensors may see detonation.
    If you are at MBT, that's the best you are going to get, going more or less is just going to get less torque.

    So apply white5.0s logic of timing descends as load increases to the MBT tables, with a slight increase as RPM climbs and put the borderline tables just slightly less than where you are picking up knock with your knock sensors, after verifying you are not getting false knock. Detonation at less than MBT is what you are looking for. If you are at MBT, the knock sensors well still reduce timing if they sense knock, putting you into "borderline."
    I underatand that but im not hardly seeing any positive knock thats an issue. Im having the opposite. When it starts stumplig the knock sensor starts adding alot of timing. On my most recent one it was seeing 5.5 degrees added to timing (one I just pulled) with 0 spark retard across the board. I monitor knock from poaitive 5 to -10. I have redone all my spark charts and it is better but there are a few areas still demanding alot of timing at part throttle possibly due to the fact im this specific area on the 3.7 ford yanks alot of timing. I'll post pictures in a minute of the positive timing its adding.

  11. #11
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    You will probably find you are going to be at MBT a lot more than borderline on E85. Ford doesn't make the engine very detonation limited for reliability purposes.

    If you are having issues with oscillation source, make sure you don't have some torn differential, motor or trans mounts. Also make sure your MAP sensor signal is not to noisy, just like a MAF you want that signal petty smooth during steady state conditions. If it's noisy this could be triggering expressive tip in and tip out events and that will trigger the oscillation source. When that happens timing is what ever the ecu thinks it should be to help.