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Thread: Concerned and aggrivated

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    Lifetime Member Whippled 496's Avatar
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    Default Concerned and aggrivated

    First let me say that I am not making this post just to hear (see) my self talk.....I have been having this problem as well as many others have from day one of installing my COS.

    This is the OS I am running: 03190003

    I love the versatility and abilities this COS gives me with my SD tune save one HUGE problem.......extremely large Lean spikes on throttle tip-in. I see anywhere in the range of 1.35 - 1.55 BEN factors when hitting the accelerator. When i go WOT, it will actually bog for a fraction of a second until it can recover (5 or so frames later). I was about to purchase the road runner but am waiting for a resolution to this....because to be honest.....the thought of crossing over to other software has crossed my mind lately. Everyone i talk to on the other side does not have these issues when running a SD tune. Lean spikes of this magnitude are a REAL concern to me. I could always go back to closed loop, but i bought this software, spent many hoours learning and tuning, and want to be able to tune my truck the way i should be able to. The first major concern of the COS (which is now a stickey in this section) was the ECT issues at start-up...this was resolved very quickly and updates were posted. I think this situation warrants the same attention. This problem has been brought up many times, most of which were done in private meassages and I would really like to at least see some discussion on a resolution.

    I am providing a copy of my tune and a log for that tune so you can see what I am talking about. I know this is not a tuning parameter that is incorrect, this has been confirmed as a COS issue. Please help me to resolve this. Acceleration enrichment tables have been discussed as a resolution to this issue. I understand that this tune is not "spot on" by any means, but this does not account for the terrible lean spikes observed (and felt).



    Thanks,
    Jimmie
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    Last edited by Whippled 496; April 1st, 2008 at 11:55 PM.
    2014 GMC 2500HD RCLB SLE
    LML / Allison

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    Just to be fair Jimmie, the other guys have the same problem. ;-) Dewey and Holty both experience it. Dewey tunes around it (raises VE dramatically in the transition area), Holty just deals with it.

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    Lifetime Member Whippled 496's Avatar
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    Quote Originally Posted by dc_justin View Post
    Just to be fair Jimmie, the other guys have the same problem. ;-) Dewey and Holty both experience it. Dewey tunes around it (raises VE dramatically in the transition area), Holty just deals with it.

    Okay, I was told they did not have these issues. Thanks for the clarification Justin. I dont want to "Deal" with it, i want it to be correct. I dont know a "work around" that would prevent this spike, but i am not a seasoned tuner either. I am welcome to suggestions as a temporary fix, but i feel there should be a change in the code to prevent this all together. Crossing my fingers.....
    2014 GMC 2500HD RCLB SLE
    LML / Allison

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    Here's a visual example of this problem.


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    Joe (Moderator) joecar's Avatar
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    W496,

    What Justin said, this is a common thing... some people get creative with the VE table.

    Thinking Out Loud (TOL)... could the lean spike be "softened" by:
    - ramping CFOL up earlier...?
    - enabling PE at a lower MAP...?
    - zeroing the RPM delay (oh, I see the delay is zero anyway)...?

    Justin, do all the PE delay bypasses have to be met for the PCM to bypass the delay,
    this is how it works, right (I just drew a blank and I need more coffee... )...?

    Cheers,
    Joe

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    Quote Originally Posted by joecar View Post
    W496,

    What Justin said, this is a common thing... some people get creative with the VE table.

    Thinking Out Loud (TOL)... could the lean spike be "softened" by:
    - ramping CFOL up earlier...?
    - enabling PE at a lower MAP...?
    - zeroing the RPM delay (oh, I see the delay is zero anyway)...?

    Justin, do all the PE delay bypasses have to be met for the PCM to bypass the delay,
    this is how it works, right (I just drew a blank and I need more coffee... )...?

    Cheers,
    Joe
    Unfortunately, it's not something that can be solved with the current calibrations. Check the screenshot I posted. Commanded AFR of 11.25 (on the dyno). Spiked up to 15:1 before starting to settle back down.

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    Joe (Moderator) joecar's Avatar
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    I see, it spikes regardless.

  8. #8
    Lifetime Member Whippled 496's Avatar
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    I have tried some VE table creativity but it does not do much to help and ultimately results in an extremely rich idle........so i changed it back. It would seem that if (as Joe mentioned) this is a "common" issue, it would have been addressed by now. Please help Ross/Paul!!
    2014 GMC 2500HD RCLB SLE
    LML / Allison

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    the VE table looks way out of whack for a whipple combo , the problem you are experincing is due to a couple of factors , one is the software never had a tps enrichment table like a pump shot , and the other is the amount of air the whipple forces in on the throttle crack.

    having tuned a huge number of whipple combo's I can tell you the low rpm VE under boost should have a huge lump in it whereas yours is a flat line - not what the engine is seeing.

    on toad tunign makes the VE table look very differnt to what the VE table looks like under steady state load on the dyno.

    Also when doing a boosted application like you have we alwasy use a boost referenced pressure regulator so we get a psuedo pump shot from the regulator on large map changes.

    it is not EFILIVEs CO3 issue but a GM coding issue really

    I have attached a example of what I would expect the VE tables to look like , do not use in your car as it wont be right but more for your interest
    Attached Files Attached Files

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    I agree about the steady state tuning to an extent. The graph I posted up was after a few hours of steady state tuning that truck on a dyno dynamics. Had VE nailed down at all load points from 1200-4400rpm (yeah, that was "fun" in boost at full load, 2nd gear). Problem is still very apparent.

    Are we certain that there is no accel enrichment in the PCM? I've read a GM-produced LS1 document that stated otherwise. PDF was posted here at some point a while back...

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