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Thread: Dying on Coastdown

  1. #1
    Tuner in Training
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    Aug 2016
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    Dying on Coastdown

    Can't resolve an ongoing issue and wanted to post this to see if somebody can offer some guidance please.
    Overall performance is fine on car with current tune, except the engine dies on coast-down.
    Slowing to a stop and take it out of gear and coast to a stop with brakes on and it dies.
    I just need to be able to keep the RPM's up during the coast-down.
    Mods - Trick flow heads with Solid roller cam 236/244 .646/.646 111LSA +2
    I've attached tune and scan file.
    Any help would be appreciated.
    2015 Camaro LS-3.hpt1st pull.hpl

  2. #2
    Tuning Addict
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    It's VERY lean on deceleration - fix your VE and no it doesn't matter that you have it setup on MAF all of the time
    2010 Vette Stock Bottom LS3 - LS2 APS Twin Turbo Kit, Trick Flow Heads and Custom Cam - 12psi - 714rwhp and 820rwtq / 100hp Nitrous Shot starting at 3000 rpms - 948rwhp and 1044rwtq still on 93
    2011 Vette Cam Only Internal Mod in stock LS3 -- YSI @ 18psi - 811rwhp on 93 / 926rwhp on E60 & 1008rwhp with a 50 shot of nitrous all through a 6L80

    ~Greg Huggins~
    Remote Tuning Available at gh[email protected]
    Mobile Tuning Available for North Georgia and WNC

  3. #3
    Tuner Chevy406's Avatar
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    Idle > RPM:
    • Make sure all of your idle tables match - Base, Startup, VSS
    • Increase the Adaptive Idle > Min RPM Ref to 800 or 850 rpm
    • Integral > Airflow: Increase the lb/hr for negative RPM and possibly even decrease values for the positive rpm
    • Idle > Airflow > Base Running Airflow > Airflow Final Minimum: I like to have a slope in the airflow as RPM increases. I think your 1,200 - 2,500 range is too low and your neutral row is too low. Maybe also jack up the 250,400,600 columns to crutch the idle if it dips.

      Fuel:
    • Why is your PE so high from 0 to 2,500 rpm?

      Spark
    • Try adding some more idle spark (up to 20?)

  4. #4
    Senior Tuner
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    1,104
    Quote Originally Posted by Chevy406 View Post
    Idle > RPM:
    • Make sure all of your idle tables match - Base, Startup, VSS
    This can actually cause idle instability on coast down.
    The most hated, make the most power.
    93 Ranger. 5.3 D1X. 1069hp.

  5. #5
    Tuner in Training
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    Aug 2016
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    Thanks for your response sir. What table would I be able to make it richer during coastdown?

  6. #6
    Tuning Addict
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    A rpm change greater than 50rpms usually uses the VE table, so I would dial in the VE table... You'll need to fail the MAF then tune in your VE tables under the edit tab - they're called virtual VE - just make all 4 tables the same as your making changes...
    2010 Vette Stock Bottom LS3 - LS2 APS Twin Turbo Kit, Trick Flow Heads and Custom Cam - 12psi - 714rwhp and 820rwtq / 100hp Nitrous Shot starting at 3000 rpms - 948rwhp and 1044rwtq still on 93
    2011 Vette Cam Only Internal Mod in stock LS3 -- YSI @ 18psi - 811rwhp on 93 / 926rwhp on E60 & 1008rwhp with a 50 shot of nitrous all through a 6L80

    ~Greg Huggins~
    Remote Tuning Available at gh[email protected]
    Mobile Tuning Available for North Georgia and WNC