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Thread: Knock after COS #3 install, but never had knock before

  1. #1
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    Default Knock after COS #3 install, but never had knock before

    Hi, I followed the operating system 3 tutorial and I also leaned out a few cells for highway cruise. I am getting knock now whenever I go WOT. I have never gotten knock before. The car is stock. Any suggestions would be greatly appreciated.

  2. #2
    Lifetime Member 5.7ute's Avatar
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    Post your tune file so we can have a look.

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    My memory stick died on me so I can't post the file until tomorrow. All I did though was put in the cos # 3 and then put the stock z06 tune in there. I then followed the tutorial on how to set the b3647 (closed loop commanded afr) table and then I leaned out some cells in under 50 map and under 2000 rpm and I added 1.5 degrees to the high octane table in low air flow under 2000 rpm. I don't see how this hurts WOT so I figure there must need another table to update when changing over to this OS. Thanks for the help.

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    Lifetime Member Tre-Cool's Avatar
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    Check table A0014 and make sure it's set to 1.00 for all the values.

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    Yes, that table is all 1s the whole way down. I think the tutorial had me change that. I was wondering if it could be that the tutorial has you change almost all of the b3647 table to 14.63 if that could be effecting the transition into PE mode? Just a thaught. Thanks for the help, Brian

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    Lifetime Member Chevy366's Avatar
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    Quote Originally Posted by CRU SS N
    Yes, that table is all 1s the whole way down. I think the tutorial had me change that. I was wondering if it could be that the tutorial has you change almost all of the b3647 table to 14.63 if that could be effecting the transition into PE mode? Just a thaught. Thanks for the help, Brian
    Your on the right track , PE is lean , try for 12.4 to 12.8 .
    Someone said that you can set the {B3647} to handle PE with in it , the PCM will use the richer of the two tables so make sure PE is leaner than the {B3647} values in the upper kPa (90-105) .
    With COS3 14.63 in {B3647} you are in semi-open loop mode (O2 sensors controlling fueling at idle).
    Forgot to add use the {B3647} values in the AutoVE tutorial , With Tuning software open click on "Help" open the AutoVE tutorial and scroll down you will see the {B3647} table I am referring to .
    Last edited by Chevy366; June 7th, 2007 at 06:18 AM.
    2005 1500 HD , Custom OS3 SD tune .
    2006 Trailblazer
    Dinosaurs and Plants gave their lives so that we may drive , long live fossil fuel .

  7. #7
    Lifetime Member GMPX's Avatar
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    Make sure A0002 is not showing as out of range.
    Best thing to do, type in 99, hit enter. Then retype 100 and hit enter, save the file and reflash. I've seen a few tunes with weird knock problems where that value was left out of range.

    Cheers,
    Ross
    I no longer monitor the forum, please either post your question or create a support ticket.

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    ok, thanks. Is there any way to know by looking at the current table if it is out of range before I change it? Thanks, Brian

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    I looked into why I was getting knock on the cos 3. It appears that my a0001, a0002, and a0009 tables were out of range. I fixed the a0001 and a0002 by typing in 99 and then 100 again, but I can't fix the a0009 table as it shows the last column as blue like it did the other out of range values in the a0001 and a0002, but in the a0009 when I decrease the values down to 499 from the 500 max they don't show up as blue anymore, but it still reports that a0009 is out of range. I would appreciate any help. Thanks a lot, Brian

  10. #10
    Lifetime Member Chevy366's Avatar
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    Quote Originally Posted by CRU SS N
    I looked into why I was getting knock on the cos 3. It appears that my a0001, a0002, and a0009 tables were out of range. I fixed the a0001 and a0002 by typing in 99 and then 100 again, but I can't fix the a0009 table as it shows the last column as blue like it did the other out of range values in the a0001 and a0002, but in the a0009 when I decrease the values down to 499 from the 500 max they don't show up as blue anymore, but it still reports that a0009 is out of range. I would appreciate any help. Thanks a lot, Brian
    The {A0009} is Boost VE and is made up of the Main VE {B0101} 105Kpa and adding 300% to the last column and using the linear-fill button .
    When I did my COS3 , I got the "Out of Range" after flashing my .tun into the COS , so it was the first thing I did .
    Under load the default {B3647} values in the COS3 tutorial will produce knock , as you said to lean .
    Post your .tun so we can see .
    Last edited by Chevy366; June 11th, 2007 at 07:05 AM.
    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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