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Thread: Idle surging help 5.3 whipple sloppy stage 2

  1. #1
    Tuner in Training
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    Idle surging help 5.3 whipple sloppy stage 2

    Having some trouble getting the idle sorted out on the following combo:
    1999 P01 3 bar
    5.3 sloppy stage 2
    Whipple W140AX with 3" pulley and 90mm holley DBC

    Got the VE close, set the IAC 30-40 hot with the throttle body screw then reset the TPS and IAC, .5v closed.
    Attempted to dial in the IAC effective area, its fairly close as desired airflow is close to running airflow at idle.
    Idle airflow is close, I know it needs a cold start but the thing oscillates or surges at idle like crazy.
    I tried increasing and decreasing Idle Airflow with no success.
    From the log you can see it does it from startup and anytime i hit the throttle and let it return to idle.

    Any ideas? VE not close enough, spark, IAC effective area, or Idle Airflow?

    Thanks!
    11 Sierra Denali

  2. #2
    Tuner in Training
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    11 Sierra Denali

  3. #3
    Tuner awest623's Avatar
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    The main method of controlling idle speed variation is thru advancing and retarding ignition timing. On your log the spark is going crazy at idle. It's adding so much timing on startup that you're getting some knock retard too.

    Big cams tend to be more sensitive to ignition timing. Try decreasing the idle adaptive spark, it's under the spark-> advance tab.
    1998 GMC K1500 Z71
    * L31 350 Vortec
    * AUS 43lb injectors
    * Comp 08-410-8 with 1.6 rockers
    * P59 swap
    * Whipple supercharger
    * JBA headers
    * AFR 190cc heads
    * NV4500 swapped
    * Cal-Trac traction bars
    * 1" blocks, 265/70r17 BF Goodrich KO2s, 17X8.5 ALPHAEQUIPT COMMAND LT

  4. #4
    Tuner awest623's Avatar
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    Here's a log of how your spark should act at idle
    Attached Files Attached Files
    1998 GMC K1500 Z71
    * L31 350 Vortec
    * AUS 43lb injectors
    * Comp 08-410-8 with 1.6 rockers
    * P59 swap
    * Whipple supercharger
    * JBA headers
    * AFR 190cc heads
    * NV4500 swapped
    * Cal-Trac traction bars
    * 1" blocks, 265/70r17 BF Goodrich KO2s, 17X8.5 ALPHAEQUIPT COMMAND LT

  5. #5
    Tuner in Training
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    I will give that a try, do you recommend cutting those values in half or...?

    I will also note the surging is only present once you are stopped. Once you get moving it is stable and does not hang or dip.
    11 Sierra Denali

  6. #6
    Tuner awest623's Avatar
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    Sorry. I don't get on here much.

    Sure you can cut it by half. Just play with it to see what you're engine wants. The tables are pretty self explanatory