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Thread: The importance of a good Scantool

  1. #1
    Forum tyhee Site Admin GMPX's Avatar
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    Default The importance of a good Scantool

    Hi all,

    Just thought I'd give you a screen shot demo of a feature in the EFILive scantool that we believe is only available in EFILive.

    We have created some special PID's that not even the GM dealers get with the Tech2!!.
    It allows you to monitor all the parameters that make up the final spark timing values. The results are interesting......

    The first screen shot shows a cold start on a cammed LS1.
    Things to look for -
    1 - Scan Spark, this is the timing figure you see reported by all other scantools.
    2 - Base Spark, a special EFILive PID, this is the timing value the PCM has read from the current timing map it is using (eg, High Octane, or closed throttle in gear, etc).
    3 - Cat Spark, a special EFILive PID, this is the amount of timing the PCM is subtracting from the base timing figure for Cat Converter lightoff. Unfortunately GM changed the code for spark summing over the years and some programs 'subtract' the timing figure from the base spark (like this example), others 'add' the timing figure, in those cases the values in the Cat Converter Lightoff table would be -6, -2 etc, not positive numbers.
    4 - Idle Spark, a special EFILive PID, this is how the PCM attempts to control idle speed using timing (it adds and subtracts timing).
    5 - Also shown but no values are being used are the special EFILive PID's - ECT Spark, IAT Spark, Trq (Torque Reduction) Spark, Bst Konck (Burst Knock) spark.
    6 - Run Spark, yet another special EFILive PID, this is the final timing figure the engine will see once all corrections have been applied.



    So from this image you can see with any normal scantool you would be seeing a timing figure of approx 14degrees, you would then be asking yourself, BUT, i have over 20 degrees in the timing map it is running in!!.
    Now, using these special PID's you can see the reason why....

    Base Spark = 23.3degrees.
    minus Cat Lightoff retard = 23.3 - 10.2 degrees = 13.1degrees
    plus Idle Spark = 13.1 + 1.2 = 14.3degrees

    Well, well, there is our actual timing value (Run spark).
    Unfortunately the spark sums are calculated alot faster than the scantool can grab data from the PCM, so you can see differences of 0.2, 0.4 degrees in the final result simply because a parameter was updated faster than the scantool could grab it.
    In any case, it just opens up the window to exactly what the PCM is upto......
    But wait there's more, we have in development some more special PID's just like these that will help take the mystery out of Idle and Fueling.

    Cheers,
    Ross

    Of interest here's some other shots from the same car -




  2. #2
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    Wow!!! That is fantastic! Thanks Guys!
    A little treat keeps the peasants happy. :wink:

    Cheers,
    joel

  3. #3
    Forum tyhee Site Admin GMPX's Avatar
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    I've attached a zip file so you can have the same setup for the spark PIDs' as shown on my first post when you get your copy.

    Cheers,
    Ross
    Attached Files Attached Files

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    Senior Member AllCammedUp's Avatar
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    You are the man, Ross. Thanks a lot for taking the time to post up this info!
    Whitney Roberts

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    Yes indeed, this is very neat. I wonder if the competition does this...

  6. #6
    Forum tyhee Site Admin GMPX's Avatar
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    Apparently in the next release :roll:

    Cheers,
    Ross

  7. #7
    Senior Member AllCammedUp's Avatar
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    Quote Originally Posted by GMPX
    Apparently in the next release :roll:

    Cheers,
    Ross
    Yeah, but probably only after they saw this thread....
    Whitney Roberts

  8. #8
    Forum tyhee Site Admin GMPX's Avatar
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    Well, I've been wondering about a small issue I have right now where as I take off (part throttle) my timing drops to 4deg for about 1 - 2 seconds then comes good. It happens everytime and just feels crap to drive.
    With our current set of spark PID's I have discovered it is Torque reduction doing it.....but the Torque reduction spark value we currently show is actually made up of 3 or 4 other spark adders/subtractors within the traction control and torque management areas.
    So I am now testing a few new spark PID's to get to the bottom of this issue. They are -

    Traction Control Spark Retard
    Transmission Torque Reduction Spark Retard
    Brake Torque Reduction Spark Retard

    Once I can see of those 3 what is responsible I then need to hunt down why the PCM thinks it needs to do this and what table is pulling all that timing out.
    Then you guys get it all in an update at some stage

    Cheers,
    Ross

  9. #9
    Senior Member AllCammedUp's Avatar
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    RIGHT ON!
    Whitney Roberts

  10. #10
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    Quote Originally Posted by GMPX
    Well, I've been wondering about a small issue I have right now where as I take off (part throttle) my timing drops to 4deg for about 1 - 2 seconds then comes good. It happens everytime and just feels crap to drive.
    With our current set of spark PID's I have discovered it is Torque reduction doing it.....but the Torque reduction spark value we currently show is actually made up of 3 or 4 other spark adders/subtractors within the traction control and torque management areas.
    So I am now testing a few new spark PID's to get to the bottom of this issue. They are -

    Traction Control Spark Retard
    Transmission Torque Reduction Spark Retard
    Brake Torque Reduction Spark Retard

    Once I can see of those 3 what is responsible I then need to hunt down why the PCM thinks it needs to do this and what table is pulling all that timing out.
    Then you guys get it all in an update at some stage

    Cheers,
    Ross
    What vehicle type are you talking about here?

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