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Thread: E38 idle tuning

  1. #301
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    Hi Joe
    I think it is but don't seem to be able to see what is driving it.
    I have smoothed the main spark tables, the idle tables and the Coast Down in the areas where it seems it could be occuring and it still will move 20 degrees instantly than come back.
    Here's a couple screen shots
    I have changed the cal some from before
    EFI Live Scan 2B 3Dec2018.pdfEFI Live Scan 2A 3Dec2018.pdf

  2. #302
    Joe (Moderator) joecar's Avatar
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    ok, I'll take a closer look tonite when I get home.

  3. #303
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    That would be awesome Joe Thanks
    Here are the latest logs and cal. It is getting better but still not right.
    In my goofing around it wants to die as soon as I step on the clutch, LOL. People say this tuning thing is easy. There is so much intertwined.
    Attached Files Attached Files
    Last edited by TurboCamaro; December 5th, 2018 at 06:29 PM.

  4. #304
    Lifetime Member hymey's Avatar
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    Quote Originally Posted by TurboCamaro View Post
    That would be awesome Joe Thanks
    Here are the latest logs and cal. It is getting better but still not right.
    In my goofing around it wants to die as soon as I step on the clutch, LOL. People say this tuning thing is easy. There is so much intertwined.
    2006_Z06_12605731_3Dec2018.ctz
    Kym_3Dec2018_0011.efi
    Kym_3Dec2018_0010.efi
    With the later os, the hard limit in the tune for idle has been increased from 60 to 200. This has been in efilive for sometime. It used to only be in HP tuners. So I would not drill a hole unless the cam is very big. Log your P and I throttle airflow values. These are very handy.

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  5. #305
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    Sorry for my ignorance but what are you meaning by "hard limit in the tune for idle"
    Unfortunately we already put a hole in the blade on this one trying to get the surging out of the idle.
    It is a pretty serious cam shaft: 239/251 .675/.675 on a 111.5LS
    This was supposed to be a road race deal now wants to drive it on the street. I would have spread the centers a bit.

  6. #306
    Lifetime Member hymey's Avatar
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    Quote Originally Posted by TurboCamaro View Post
    Sorry for my ignorance but what are you meaning by "hard limit in the tune for idle"
    Unfortunately we already put a hole in the blade on this one trying to get the surging out of the idle.
    It is a pretty serious cam shaft: 239/251 .675/.675 on a 111.5LS
    This was supposed to be a road race deal now wants to drive it on the street. I would have spread the centers a bit.
    That's OK if you drill a hole. It won't matter, regardless what anyone says. The fitting in the manifold is basically a hole. If you block that , that changes the idle aswell.

    The hard limit Is the highest throttle opening the pcm can allow during idle and coast conditions.I don't have my laptop on me , only when I am tuning....

    If the idle is correct. Small throttle openings is IGN timing, pulse width ( you will need to be in open loop with that cam and speed density) injector timing helps, you can move this around for drivability. Idle airflow numbers play a huge part in drivability. It will all fall into place if everything is correct.....

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  7. #307
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    Thanks
    I have quite a bit of injection timing in it, 450deg I think, have moved it around some.
    When you talk idle airflow numbers are you specifically talking minimum airflow or others as well.

    I can see the ignition timing moving, swings +20Deg, but don't see where it's coming from. I have the spark idle compensation reduced quite a bit and allow the RPM to move some before it compensates.

    When you say open loop do you think AFs are affecting this as the trims seem to be OK.

  8. #308
    Lifetime Member hymey's Avatar
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    If the timing swings dig a bit deeper there.

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  9. #309
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    Thanks
    Any ideas what I may be missing.
    I ensured the idle base spark, Coast Down Spark and Main Hi Oct & Lo Oct Spark are flat in the areas it is surging. The Spark Idle compensation are significantly less than the amount the spark is moving. Are there pids to see Spark Idle Compensation and if it is using the Idle, coast or main spark tables. Or other?

  10. #310
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    Quote Originally Posted by TurboCamaro View Post
    Thanks
    Any ideas what I may be missing.
    I ensured the idle base spark, Coast Down Spark and Main Hi Oct & Lo Oct Spark are flat in the areas it is surging. The Spark Idle compensation are significantly less than the amount the spark is moving. Are there pids to see Spark Idle Compensation and if it is using the Idle, coast or main spark tables. Or other?
    I took a quick look at your log and cal. I believe the timing fluctuation is from the difference in timing between your base idle/coast down tables (~12-15 degrees) and the high octane (40 degrees). Any time you are on the gas it will jump to 40 and then drop to 12-15 when you left off. I usually try to match the high octane and coast down tables so there are not huge jumps in timing when you let off the gas and are moving. I also leave the timing correction close to stock, as it works pretty well to control idle speed. I made some changes to your cal, see attached.
    Attached Files Attached Files
    00 Silverado Z71, LQ9 w/ LS3 heads, BTR cam, Whipple 2.9@8#, 4l80E

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