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Thread: Knock Learn Factor... while VE tuning

  1. #1
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    Knock Learn Factor... while VE tuning

    Did some VE tuning recently and noticed my KLF went to 0... I assume due to defaulting on low timing table. I matched the tables for tuning, but afterwards KLF will take awhile to get back to 1. How do tuners account for this? Do they just keep the tables equal for a bit? Or is there a trick so KLF does not go to 0 when failing the MAF?

    2001 C5 coupe

  2. #2
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    It does goto 0 and as far as I know people usually just temporarily copy the tables over. I never left the tables equal, just set them back, after all, the KR will recover...
    99 TA, Texas Speed LS376, PRC heads, 233/239 cam, Fast 92mm, 95mm TB, card style MAF, Tick TR6060, Strange 4.11 12 bolt axle & clutchpack diff, Strano springs/dampers, Vette 18" wheels, Vette disks, CTS-V calipers, 16lb flywheel, long tube headers, no cats.

  3. #3
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    So KLF is stuck at 0.45 even after filling the tank... I take it maybe it needs a few tanks.

    What if no error reported is checked during VE tuning... would KLF still zero out?

  4. #4
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    Bumping this... I have been stuck at 0.45 KLF for months and many fuel tank fills. I have matched high and low tables so no effect, but would like to have a low table just in case.
    This happened after VE tuning... which it did ramp from 0 to 0.45, but been stuck once reaching 0.45.

    What can I do to get it back to 1.00?

  5. #5
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    It does NOT use the fuel level, nor anything else, except driving conditions, to change the KL value. I don't know where this odd idea plastered across the net came from!

    The only way the KL figure will climb is if you spend significant time in the KL "learn" figures set by your tune. If you don't drive enough whilst being "in the window" it won't climb. I don't know what your settings are but this is where they are for reference;

    Capture.JPG

    If your figures are not in these limits it does not learn, particularly usually the default MAP affects it, because its usually different in a tuned car. Also btw I am not so sure it will learn if the tables are equal either.

    BTW, if you could spend consistent time in the learn area, e.g. cruising at "some speed", lol, it will take at least half an hour to learn back to 1, perhaps even an hour of that. ...
    Last edited by dermotw; 06-29-2017 at 04:05 AM.
    99 TA, Texas Speed LS376, PRC heads, 233/239 cam, Fast 92mm, 95mm TB, card style MAF, Tick TR6060, Strange 4.11 12 bolt axle & clutchpack diff, Strano springs/dampers, Vette 18" wheels, Vette disks, CTS-V calipers, 16lb flywheel, long tube headers, no cats.

  6. #6
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    I've never seen my KLF move from 0.75
    No idea why..


    Edit:
    Quote Originally Posted by dermotw View Post
    it will take at least half an hour to learn back to 1, perhaps even an hour of that. ...
    Now I know why ^
    Last edited by Mr. Smith; 08-15-2017 at 12:00 PM.

  7. #7
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    Hmm thats weird folks, mine climbs ok... Allegedly it climbs purely based on time running with no KR detected (assuming all the conditions in the table are met). It does seem like there is some sort of time delay as well though... it climbs in small steps, e.g. .78 > .80 > .82 etc. and I don't know what it bases the steps on! Maybe the same table it uses for decay?

    EDIT: heres a couple of pictures; 1st, recovery, as you see it takes 30 mins and it only climbs when I'm cruising at 60mph or so really. the marker is at a point where it's not climbing...

    Capture.JPG

    2nd, example of KR changing the KL value, actually there are 3 KR bursts, the 3rd is under 1 degree and does not even affect it. With my own table settings, you see that it recovers quite fast, but that might not be true for another vehicle. Note the different scales! You can see it takes repeated KR to 'drag' the KL back down.

    Capture.JPG
    Last edited by dermotw; 07-01-2017 at 03:59 AM.
    99 TA, Texas Speed LS376, PRC heads, 233/239 cam, Fast 92mm, 95mm TB, card style MAF, Tick TR6060, Strange 4.11 12 bolt axle & clutchpack diff, Strano springs/dampers, Vette 18" wheels, Vette disks, CTS-V calipers, 16lb flywheel, long tube headers, no cats.

  8. #8
    Senior Tuner kingtal0n's Avatar
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    If I understand correctly, the low octane timing table is blended into the high octane table depending on Knock Learn value? 1.0 being fully in the high octane table?

  9. #9
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    Yes, 1 = Hi, 0 = low, and 0.5 would be halfway between....
    99 TA, Texas Speed LS376, PRC heads, 233/239 cam, Fast 92mm, 95mm TB, card style MAF, Tick TR6060, Strange 4.11 12 bolt axle & clutchpack diff, Strano springs/dampers, Vette 18" wheels, Vette disks, CTS-V calipers, 16lb flywheel, long tube headers, no cats.

  10. #10
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    Hey! Thanks much for the response... I don't get email notifications of a post so I missed this.

    My car is basically a track car that's sometimes driven on the street, but spend plenty of time in the KL parameters. And just a very mild tune for E30.
    I've attached the tune if anyone is curious. Been pegged at 0.45 since my OP.
    Attached Files Attached Files

  11. #11
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    UPDATE: back to 1.00... boy that took awhile!
    I don't log much, so not sure when it happened but sometime between my last post and now... from 0.45 for months to suddenly 1.00. I was loading a tune revision yesterday and noticed it.