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Thread: CASE Relearn

  1. #1
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    Default CASE Relearn

    I installed a cam back in September and upgraded to a 02 OS system a few months back. While browsing the forum here and at LS1tech I was reading about a CASE relearn.

    My question is with the new cam and upgraded OS would a crank position sensor relearn be the smart thing to do?

    I eventually plan to run my RR full time in the car, but for now I am still using the stock PCM.

    R/

    Frat

  2. #2
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    You shouldn't need to do the CASE even after a full flash as all the cal details are retained. I am no expert but if you needed to re-learn I think you'd know by now (presumably the car would either not run, or run like a bag of spanners if it needed doing).

    Rgds

    Jim

  3. #3
    Joe (Moderator) joecar's Avatar
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    A CASE relearn is needed if:
    - crank sensor is replaced,
    - PCM is replaced,
    - stall converter is installed (change of "rotational mass").

    Otherwise as Jim stated, the PCM stores CASE info in non-volatile memory which is not altered by reflashing.

  4. #4
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    Thanks for the feedback, guys. I appreciate it.

    By the way.... whats a "bag of spanners"?

    Thanks again.

    R/

    Frat

  5. #5
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    Quote Originally Posted by joecar
    A CASE relearn is needed if:
    - crank sensor is replaced,
    - PCM is replaced,
    - stall converter is installed (change of "rotational mass").

    Otherwise as Jim stated, the PCM stores CASE info in non-volatile memory which is not altered by reflashing.

    Joe, you mention a stall being added.. You think not doing this could casue idle problems? I have some idling gremlins I cannot get out and I have a 4k stall and a CASE has never been prefomred that I am aware of..
    EFILive newbie

    1999 Camaro SS A4 | LME Forged 347 | Yank SS4000 Stall | 226/234 Cam | Patriot LS6 Style heads 2.055 / 1.57 57cc 11.3 SCR | FLP Long tube headers

  6. #6
    Joe (Moderator) joecar's Avatar
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    Joel,

    From what I've previously read from GM drivability class material, it seems that the PCM uses CASE info in it's misfire detection algorithm (PCM uses crank sensor position error limits to analyze the rate of change of crank motion, and if it's outside computed "envelope", then it flags a misfire...)...

    The engine's rotating mass "moment of inertia" (which includes the TC) has a direct influence on the rate of change of crank motion...


    How this relates to idle: I don't know what the PCM does if it detects misfires at idle... ...I have no idea.

    How this relates to TCC lockup: the PCM momentarily unlocks the TCC when misfires are detected.

    So, for the TCC, it would be a good idea to do a CASE relearn anyway.

    Joe

  7. #7
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    Quote Originally Posted by Fratsit
    By the way.... whats a "bag of spanners"?
    Frat
    What my car sounds like after I've been tinkering with it

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    Frat

  9. #9
    Joe (Moderator) joecar's Avatar
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    Talking Bilingual Translation...

    spanner (UK) == wrench (US)

  10. #10
    Lifetime Member Biggsy's Avatar
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    spanner (AUS) == loser/idiot (world)

    Quote Originally Posted by joecar
    A CASE relearn is needed if:

    - stall converter is installed (change of "rotational mass").
    OK, did not know that. I changed my torque converter to a 3000rpm stall a few months back. Its physically smaller/lighter than the original one. So you're saying I should do a CASE relearn?

    I haven't noticed any difference since the install (except severe lack of traction to the road! )

    What problems should/could happen?

    Dave.
    Last edited by Biggsy; February 5th, 2007 at 07:45 PM.

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