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Thread: Climbing RPM while cruising in nuetral

  1. #1
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    Climbing RPM while cruising in nuetral

    Hey guys I need some help with the tune on my Silverado. It is an 05 RCSB with the 4.8 and a 5 speed. I recently installed a small cam from cam motion and while tuning have found something weird when driving. When changing gears while it is in neutral or just coasting in neutral my RPMS go up while my throttle position doesn't change at all? Any ideas on what could cause this? This wasn't happening before the tune and I thought maybe it is the fuel decel cutoff? I will try and re-enable it tomorrow and see if it helps at all. let me know if any more info is needed, thank you to anyone who takes a look.
    Attached Files Attached Files

  2. #2
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    High RPM disable = 200. Don't try and run it in MAF only mode. Tune the VE too and run it in blended. Also you have a huge fat finger error in the MAF table at 4375 HZ.

  3. #3
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    Are you tuning this yourself?
    Its throttle cracker (ECM 12130) that is adding all the airflow.

    Add that and throttle follower to your channels .


    Why the crazy spark for idle Over/Under speed?

    You have a typo in your IAT Spark table as well.

  4. #4
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    It looks like somebody tried to tune idle parameters before getting the fueling right. And the spark tables are a mess. The low octane table is higher than the high table in places. I quit looking after that.

  5. #5
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    Quote Originally Posted by RDF1 View Post
    Are you tuning this yourself?
    Its throttle cracker (ECM 12130) that is adding all the airflow.

    Add that and throttle follower to your channels .


    Why the crazy spark for idle Over/Under speed?

    You have a typo in your IAT Spark table as well.
    The throttle cracker table is stock for that calibration. So is the idle airflow table so I don't know where the extra air is coming from. The only changes I saw in the idle tab comparing it to a stock 05 4.8 M5 file I have is the idle speed was increased from 600 to 900 rpm.

  6. #6
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    So do i need to disable throttle cracker? And I was looking at a guide for idle tuning with a cam and was messing with the over/under speed. Guy said more or less you go in each direction will have the cam idle differently. And thank you I am not sure why that was there I haven't messed with that yet.

  7. #7
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    Take your stock file and only make the least changes necessary to keep the engine running at idle. Raising your base idle speed is sometimes enough. Once the engine will stay running, dial in your VE and MAF for the correct fueling. Unless you see a lot of knock retard, don't even mess with timing yet. If you only did a cam swap with nothing to raise compression this should not be an issue. Only AFTER your fueling is correct do you have any chance of properly dialing in your idle, and you will be very surprised at how little you have to change other than base running airflow.

  8. #8
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    The first step should be putting the idle adaptives back to stock. What you have would give unpredictable results.
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  9. #9
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    Quote Originally Posted by Alvin View Post
    The first step should be putting the idle adaptives back to stock. What you have would give unpredictable results.
    They are stock. The only thing changed in the entire idle tab is the idle speed.

  10. #10
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    idle spark adaptive are not stock.
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  11. #11
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    There is a difference in those and your original statement.