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Thread: 3 questions

  1. #1
    Lifetime Member eboggs_jkvl's Avatar
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    Default 3 questions

    The attached file has three things happening that I need stopped.

    Thing #1: AFR event frames 4915 - 4988 & 8652 - 8667 (Edit: When these events happen, the car snaps from closed loop to open loop for the event and then goes back to closed loop)

    One occurs at idle (and often I might add) that I can feel and one happened at 37MPH which I could not feel. When it happens at idle, my idle dips pretty heavily (400's) It was not pronounced on this recording but I can feel the Power Steering shudder when the event occurs.

    Thing #2: KR. In open loop, my shifting has 0 KR. After the car gets hot and in closed loop, it goes into KR especially at 3rd gear.


    Thing #3: Idle dip to very low RPMs when clutch is depressed as in coming to a stop.
    Open loop
    frame 776 RPM 496
    and 1216 RPM 376
    Closed loop
    frame 3905 RPM 444

    This is constantly happening and the dives in RPM affect the Power Steering enough to make the steering wheel to shudder.



    Ok, that's it.


    TIA,


    Elmer
    Attached Files Attached Files
    Last edited by eboggs_jkvl; October 12th, 2010 at 06:52 AM.
    2014 Corvette Convertible, Torch Red, A6, Z51, 3LT, NPP Exhaust



  2. #2
    Lifetime Member eboggs_jkvl's Avatar
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    Ok then, I'm swamped with responses. Let's try another question.

    I just loaded the stock High octane Table back in to the ECM. My scan shows KR of say... 7 degrees. I highligh the KR, switch to the tune file and see the cell that is indicated as the KR cell. So, I take the reading in the cell, lets say 27 and reduce it by 7 to 20. Do I need to blend the surrounding cells to not have a "spike" down in the table or is the E38 fast enough that a blend would be unecessary? Is this the proper way to make adjustments to the spark table?


    Elmer

  3. #3
    Joe (Moderator) joecar's Avatar
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    Hi Elmer,

    In your example, try reducing from 27 to 24 (i.e. a lesser drop)... I would blend surrounding cells since the surrounding cells are at operating conditions that are only incrementally different than the current cell (i.e. you may get knock in those surrounding cells also)... i.e. there are no discontinuities in physics (for tuning purposes)...

    proper way...? Anything called proper is always debatable, you already know that

    the ECM interpolates between cells, so it's not a matter of the the ECM blending, but a matter of where it's starting from (i.e. the nearby cell).

    -Joe

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    Elmer, what is the setup you are running in the engine and tune? Difficult to know how to respond without understanding some of the context.

  5. #5
    Lifetime Member GAMEOVER's Avatar
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    ELmer, Are you atleast running 91-93 Octane? What spark plugs you using?
    2008 2WD Ext.Cab Silverado 1500 6.0 V-MAX E38(L76) & T42(4L70E) MAF Only CL Corvette Servo AFE CAI INNOVATIVE LM-2 WBO2

    FLASHSCAN V2 & AUTOCAL

  6. #6
    Lifetime Member eboggs_jkvl's Avatar
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    My Sig shows all of my options on the car.

    My KR did great that time, I blended around the offending cell and did not repeat the KR. I reran the test with harder acceleration and hit more KR, which I adjusted the cells again to fix the octane table.


    I run ONLY 93 octane in the car. NGK TR6 plugs. Gapped @.035

    OK, now what cute little table do I slap to reduce the "Cruise Control" effect of the throttle. When I lift, it is not coming down in RPMs quite like I expect. I think the "Dipping" I was chasing was the 52 degrees of spark I was running. I simply had to much spark everywhere on the table. I loaded the stock spark table back in and this is what I'm tuning now. I think I have a good grip on the spark table. I'm going to run it with this for a while to make sure it has every opportunity to "learn" and see how it runs. I just need to tweak that air flow table, whatever it is, to get the RPMs to come down a bit faster when I lift off the throttle and I might be getting close to being comfortable with the tune.

    Elmer
    Last edited by eboggs_jkvl; October 16th, 2010 at 09:49 AM.
    2014 Corvette Convertible, Torch Red, A6, Z51, 3LT, NPP Exhaust



  7. #7
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    Quote Originally Posted by eboggs_jkvl View Post
    My Sig shows all of my options on the car.
    So that means you are running a stock LS2 engine with Edelbrock blower? With some NFI GM RPO's. What changed that started giving you OL/CL snaps.

  8. #8
    Lifetime Member eboggs_jkvl's Avatar
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    The OL/CL snaps are a total mystery to me. I do not know what "tune" my tuner started with. I'm really getting close to putting the entire stock tune back into the car and resetting the MAP and Injectors to the new stuff. I'm tired of guessing what the heck is in the tune.

    I just put the stock Engine Operation, Minimum idle airflow numbers back in (B1829). Going for a drive now to see what that causes on the lifting of the throttle pedal and the RPM drop.

    Elmer

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    Quote Originally Posted by eboggs_jkvl View Post
    The OL/CL snaps are a total mystery to me. I do not know what "tune" my tuner started with. I'm really getting close to putting the entire stock tune back into the car and resetting the MAP and Injectors to the new stuff. I'm tired of guessing what the heck is in the tune.

    I just put the stock Engine Operation, Minimum idle airflow numbers back in (B1829). Going for a drive now to see what that causes on the lifting of the throttle pedal and the RPM drop.

    Elmer
    Yes its worth starting again. Do a compare against your original tune...there may be some standout odd ball issue. Its amazing what some tunes have done to them...

    Or post the tune for a quick examination...

  10. #10
    Lifetime Member eboggs_jkvl's Avatar
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    Well, the cruise control is gone and the car is driving perfectly. I still have the dieseling, darn. I think I need to start over. I'm going to set the MAP, injectors, and high/low octane tables from what I'm running now into a stock tune base and see what happens. I keep putting things back to stock to make the car perform properly so I may as well be SURE that EVERYTHING is set to stock and start over.


    Elmer

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