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Thread: a/f c6 z06 s/c question please help!!!!!

  1. #1
    Tuner in Training
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    a/f c6 z06 s/c question please help!!!!!

    (im a bit of a newb so plz forgive me) got a heads cam c6z with an A&A vortech si kit on pump/meth on bit of a conservative tune one thing i noticed logging thecar and on my aem gauge is it goes over 14.7 often every time i cruise it like youll see in the log and im not talking it going into the 15s like all the way the way up to 29 a/f!!! just wondering if its something serious enough to bring over to my tuner also the car likes to surge at 20-30mph at 1500 rpm cruising its pretty bad dont know the specs of the cam more of a how you say mid sized cam tho really appreciate the help thank you!!!!c6z warm hit with jake.hpl

  2. #2
    Tuning Addict 5FDP's Avatar
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    When you are cruising and you let off the throttle and coast, the computer will enter DFCO (decel fuel cut-off). You can watch the injector pulse width almost flat line, the o2 sensors nose dive and the fuel system status sometimes changes to OL/accel for open loop. So because the injectors shut off and turn the engine into just an air pump with no bang, the wideband will show super lean.

    You can disabled DFCO under and over certain speeds in most cases or just turn it off for good.

    I'd have the tuner look into that. Also maybe look into why the commanded lambda is so far off from your reported lambda with your wideband. It's asking for .87 but your wideband is showing .76. The .76-.80 is a great target to shoot for but the computer is asking for a leaner mixture, showing that the airflow model needs more work.

    Also add knock retard to your logs, for sure something you need to watch.
    2016 Silverado CCSB 5.3/6L80e, not as slow but still heavy.

    If you don't post your tune and logs when you have questions you aren't helping yourself.

  3. #3
    Tuner in Training
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    thank you for knowledge deff gonna look into into it