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Thread: Rough Idle After EFILive Flash

  1. #1
    Lifetime Member samh_08's Avatar
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    Default Rough Idle After EFILive Flash

    I simply read the stock tune from a 2011 Silverado E38, added 10% to the 'Torque Model' tables and flashed the tune into the ECM after licensing it.

    My question is, being we dont necessarily have access to every table in this ECM, do we lose anything by flashing an EFILive tune over a stock cal?

    I noticed it right away when I started so I let it be cause I had to drive 100 miles anyways today, but it was still idling much rougher after the trip.


    Ideas, info?
    Thanks!

  2. #2
    Joe (Moderator) joecar's Avatar
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    Re-flash the tune and see what it does.

  3. #3
    Lifetime Member samh_08's Avatar
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    Today it has been good, completely different than yesterday. I'll leave it be for now but Im still curious about my question above..

  4. #4
    Lifetime Member Chevy366's Avatar
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    Quote Originally Posted by samh_08 View Post
    I simply read the stock tune from a 2011 Silverado E38, added 10% to the 'Torque Model' tables and flashed the tune into the ECM after licensing it.

    My question is, being we dont necessarily have access to every table in this ECM, do we lose anything by flashing an EFILive tune over a stock cal?

    I noticed it right away when I started so I let it be cause I had to drive 100 miles anyways today, but it was still idling much rougher after the trip.


    Ideas, info?
    Thanks!
    Something that I have noticed and complained about a few times, it seems as if EFILive does something to the EPROM that clears more than it use to. When I say "use to" I mean from several years back, you could flash a tune and see no real difference in idle, or idle would respond quicker and idle normally, now it seems that the idle has to relearn more parameters and will run rough for several drive cycles before it calms down and idles correctly, at least that has been my experience lately. The more you let it idle the faster it relearns idle it seems. SRT can show ready and it will still idle rough, I thought maybe it was O2 sensors not ready but not the case.
    I have logged data before but did not see anything that just stood out. I know mine will throw a P0300 code every time I reflash on first idle, I clear that and it will not reappear but will still idle rough for days or several drive cycles.

    No help I know, but at least you are not alone.
    2005 1500 HD , Custom OS3 SD tune .
    2006 Trailblazer
    Dinosaurs and Plants gave their lives so that we may drive , long live fossil fuel .

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    Lifetime Member macca_779's Avatar
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    But if the idle settings are good any learning will be negligible.

  6. #6
    Lifetime Member samh_08's Avatar
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    Quote Originally Posted by macca_779 View Post
    But if the idle settings are good any learning will be negligible.
    So a completely stock pickup's idle settings aren't too close?

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    Quote Originally Posted by samh_08 View Post
    So a completely stock pickup's idle settings aren't too close?
    I full flashed an E38 and stock idle was spot on... LS1B is another story, but I've been able to modify the settings so mine is spot on after a full flash. I wonder if this is related to an incorrectly calibrated MAF (cal changing with age and cleanliness)
    14 GMC Sierra
    5.3L CC SB 4x4
    Basic tuning....

  8. #8
    Lifetime Member Chevy366's Avatar
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    Quote Originally Posted by samh_08 View Post
    So a completely stock pickup's idle settings aren't too close?
    I doubt that seriously, don't you?
    Quote Originally Posted by Wheelz View Post
    I full flashed an E38 and stock idle was spot on... LS1B is another story, but I've been able to modify the settings so mine is spot on after a full flash. I wonder if this is related to an incorrectly calibrated MAF (cal changing with age and cleanliness)
    Does the same thing with a Speed Density tune, no MAF? Have completely built a new tune from scratch, same thing and by Script method, same thing.
    2005 1500 HD , Custom OS3 SD tune .
    2006 Trailblazer
    Dinosaurs and Plants gave their lives so that we may drive , long live fossil fuel .

  9. #9
    Lifetime Member samh_08's Avatar
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    Quote Originally Posted by Chevy366 View Post
    I doubt that seriously, don't you?
    To be honest, I've only tuned modified vehicles so I guess I just assumed factory was very close. Apparently not the case?

    On a side note, should I be doing a 'full flash' the first time I flash an EFILive tune coming from stock?

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    Quote Originally Posted by Chevy366 View Post
    I doubt that seriously, don't you?

    Does the same thing with a Speed Density tune, no MAF? Have completely built a new tune from scratch, same thing and by Script method, same thing.
    I would recommend adding air in 5-10% increments to B1829 for revs below 800, and maybe adjust B1832 as well if it's struggling to start without throttle input. If it struggles when the A/C starts try adding air to B1825 and B1826. Just small percentage amounts and see how much it changes. Those tables should have similar effects to the ones I changed on my LS1B to make it idle correctly after a full flash

    It took me all day to get my LS1B to idle right when I went speed density, but I didn't let I learn. I trial and error added airflow till it would idle on its own, and my idle desired airflow values (B4307 in my tune) are almost double what they were from factory (but I also elevated idle speeds slightly).

    Also I've noticed the VE table's correctness influences idle quite a bit in SD. If you change your VE values it using to idle, expect your idle to have to relearn or manually tweak the values.
    14 GMC Sierra
    5.3L CC SB 4x4
    Basic tuning....

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