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Thread: $EE Timing - Where is the Spark Advance Coming From?

  1. #1
    Fuel Injected! spfautsch's Avatar
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    $EE Timing - Where is the Spark Advance Coming From?

    I recently "rebooted" my tune back to eliminate some SD tuning I'd done a little haphazardly, and am experiencing some cam surge (that I've already eliminated in previous tunes). It's happening around 1100-1500 rpm between 30-50 map. What I cant figure out for the life of me is where the tune is getting a commanded 31 degrees of timing (see tables). I have detuned the idle speed timing correction and stall saver verbatim from steveo's tips. Also EGR adder table has been zeroed.

    spark-map.jpg

    Yet I'm seeing 31 degrees commanded all over the place when in cell 17. I know this is where the surge is coming from. I just can't seem to wrap my head around how to get commanded spark down into the 28-29 degree range like I'm asking for.

    surge-frame.png

    Edit: I'm also seeing a small number of frames with 31 degrees SA in cells 2 and 6.

  2. #2
    Fuel Injected! jthompson122183's Avatar
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    the infamous $EE "mystery spark" "ghost spark" adder? maybe What xdf are you using?
    Last edited by jthompson122183; 05-22-2017 at 04:15 PM.
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  3. #3
    LT1 specialist steveo's Avatar
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    - cell 17 is for decel
    - you are at 0% tps
    - it is using the 0% tps spark table
    - in that table, it's commanding 30 degrees

    this isn't so wrong

  4. #4
    Fuel Injected! spfautsch's Avatar
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    Quote Originally Posted by jthompson122183 View Post
    the infamous $EE "mystery spark" "ghost spark" adder? maybe What xdf are you using?
    This guy's. V

    Quote Originally Posted by steveo View Post
    - cell 17 is for decel
    - you are at 0% tps
    - it is using the 0% tps spark table
    - in that table, it's commanding 30 degrees

    this isn't so wrong
    Except that there are no cells even two detached from the next higher RPM + MAP with more than 30 degrees. 30 + 0 = 31? Baaaaah! :-)

    I've seen instances where it seems to have rounded up RPM when not at 0% tps, but I'm not wanting to break out the old hacking tools to disassemble. Just thought I'd ask in case anyone had a handle on it. I guess I'll refer to it as the "ghost spark adder table" and move on with life.

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    Carb and Points! Daemon's Avatar
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    Hello. I'm sorry for writing to the old thread.
    Has there been any new information about this during these 4 years?
    I have same problem with my 94' impala LT1.
    PCM has detected many knocks at WOT (with and without PE). In logs the ignition timing absolutely mismatched its tables.
    In table - 18, at fact - 30; in table - 22, at fact - 32, in table - 35, at fact - 38 degrees.
    All other adj tables are set to 0 (like a ERG (it's deleted), Minimum spark advance, Coolant temp correction, etc.)
    I seem to be stumped.
    I need help.. What should I do?
    1994 Chevy Impala SS
    1992 Chevy Caprice 9C1

  6. #6
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    Extra timing comes from a scalar to compensate for EST lag. It is something like a 1 degree added each xxxx rpms.

    You can also look at the wrong tables, 18 to 30, seems highly unlikely.

    Post a log and a bin and I can tell you more.

  7. #7
    Carb and Points! Daemon's Avatar
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    I can't just reduce table valves because it happens ... sometimes. And I didn't find any regularity.
    But I noticed that this usually happens at a high MAT value.
    1994 Chevy Impala SS
    1992 Chevy Caprice 9C1

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    Carb and Points! Daemon's Avatar
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    kur4o, thank you mate.
    Now I can't find it... I'm sorry. Maybe I deleted it :-(
    I couldn't find it in today logs too, they clear of that.
    If I found it again I'll post it at once.
    1994 Chevy Impala SS
    1992 Chevy Caprice 9C1

  9. #9
    Carb and Points! Daemon's Avatar
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    kur4o, hello, yes, I posted incorrect values. I found where I saw that. 18 to 30 - it's my mistake. I just was openned new log and forgot to close old log at experimental tables, I'm so sorry.
    Just I saw something that is not there. I fought with him before and I saw it again. I probably need a vacation
    Before I really had ghost spark adder and I had ~2-4* overshoot at WOT.

    I found "Unknown Spark Adder" in "Exterimental" at "EEX.xdf" with this comment:
    "This is an additional spark-per-rpm factor that can screw with WOT spark. Apparently setting it to zero is a good idea."
    After that I set it to 0 and they completely disappeared!

    An explanation of this parameter is given here. That's what you told me about - EST lag compensation. Do I need it?
    http://www.gearhead-efi.com/Fuel-Inj...ll=1#post57929
    http://www.gearhead-efi.com/Fuel-Inj...ll=1#post64050

    Thank you for your willingness to help.

    P.S. Interestingly, my engine didn't need a lot of spark advance all over the table. Efficient LT1 combustion chambers allow me to keep WOT at 33 degrees at a compression ratio of 10.6 with cast iron heads, mild cam and 160*F thermostat on regular gas.

    EDIT: I find it in last "EEXTRA" xdf: "12046 EST system lag time" with a comment:
    "POSS SPARK PE ADDER VS x12 low reference
    some adder or mult to closed tps spark and minimum spark advence vs rpm tables
    "

    EDIT2: That's needed. I think.
    I have dramatically improved engine responsiveness and power at high RPM after turning this on, on premium gasoline with a soft ignition table (F-Body firmware is taken as a basis).I have an extra spark of +4 at 6000.
    I attach my bin and a short trip log.
    At high RPM, there is a slight vacuum and the adjacent column of the table is used, I will subtract 1 from that later.
    Attached Files Attached Files
    Last edited by Daemon; 05-25-2021 at 04:56 PM.
    1994 Chevy Impala SS
    1992 Chevy Caprice 9C1

  10. #10
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    Thanks for the compehensive write up on the spark adder.

    What you see as added spark is actually the time needed to trigger the spark. I leave mine on and adjust the main spark at the problem areas. I too noticed that cammed cars don`t like much advance.

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