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Thread: E78 controller fans for L96 engine

  1. #1
    Tuner in Training DanSchafer93's Avatar
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    E78 controller fans for L96 engine

    I have seen a number of people including myself dance around this subject for quite some time. Engine is a L96, 6.0L out of a 2012 Sierra 3500 cab and chassis. Are there any good answers to getting the fans working appropriately? Currently I have them just locked on since I have been daily driving the rig to dial in VVE tables and MAF. Attached are two screenshots of the settings I was using while trying to get the fans to only kick on at a certain temperature. Anybody have any ideas??

    Thanks,
    Dan
    Attached Images Attached Images

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    I never got mine to work either.. there is a car that has the same ecm Chevy Cruz i believe i was thinking about buying an ecm for a cruz and transferring the v8 data to the crus ecm. i believe the the cruz has the proper segment to enable the fans to work just like the gen 3 ecms and flex fuel.

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    I've seen a few threads on this and I'm curious, why aren't you just controlling your fans with a thermostatic controller? It's like $60 for a kit. I have an E78 ECM and I plan to use that.

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    Tuning Addict blindsquirrel's Avatar
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    Because having everything integrated into the ECM is really nice. Compressor control, fan speed based on both ECT & AC pressure, fan after-run for heatsoak, etc.

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    Quote Originally Posted by DanSchafer93 View Post
    I have seen a number of people including myself dance around this subject for quite some time. Engine is a L96, 6.0L out of a 2012 Sierra 3500 cab and chassis. Are there any good answers to getting the fans working appropriately? Currently I have them just locked on since I have been daily driving the rig to dial in VVE tables and MAF. Attached are two screenshots of the settings I was using while trying to get the fans to only kick on at a certain temperature. Anybody have any ideas??

    Thanks,
    Dan
    There are a lot of fan parameters not defined in HPT, but so required for proper tuning.

    Fan %DC requests:
    + vs ECT
    + vs ACP
    * vs EOT (Engine Oil Temp)
    * vs TFT
    * vs Air Temp (Selectable IAT, IAT2, Charge Temp)

    There are TWO sets of Fan State Transition tables for Cold and Hot weather depending on Ambient Air Temp so it gives us another two thresholds - Cold and Hot AAT.
    For PWM controlled fans to avoid %DC fluctuation GM have implemented shadow inverted tables (temp/kPa vs %DC), lets call them "Fan Keep", for each %DC request. Improper tuning of those tables or contradiction with requests can lead to fan stuck on even with discrete fans.

    In short using HPT you can dial only about 20% of required fan parameters.
    Last edited by verlon; 12-30-2022 at 11:52 AM.
    2011 Cadillac Escalade L94 w/LS3 valves and valve springs

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    Quote Originally Posted by verlon View Post
    There are a lot of fan parameters not defined in HPT, but so required for proper tuning.

    Fan %DC requests:
    + vs ECT
    + vs ACP
    * vs EOT (Engine Oil Temp)
    * vs TFT
    * vs Air Temp (Selectable IAT, IAT2, Charge Temp)

    There are TWO sets of Fan State Transition tables for Cold and Hot weather depending on Ambient Air Temp so it gives up another two thresholds - Cold and Hot AAT.
    For PWM controlled fans to avoid %DC fluctuation GM have implemented shadow inverted tables (temp/kPa vs %DC), lets call them "Fan Keep", for each %DC request. Improper tuning of those tables or contradiction with requests can lead to fan stuck on even with discrete fans.

    In short using HPT you can dial only about 20% of required fan parameters.
    So, does manipulation of those values require a GM tuner?

  7. #7
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    Quote Originally Posted by GDiddy99 View Post
    So, does manipulation of those values require a GM tuner?
    Oh, we can only dream about it.

    Unfortunately, the only way to properly tune most specific things is doing it yourself.
    2011 Cadillac Escalade L94 w/LS3 valves and valve springs

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    Here is an example of major fan parameters (metric) from my Escalade.

    E38_Fans.png
    2011 Cadillac Escalade L94 w/LS3 valves and valve springs

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    Quote Originally Posted by verlon View Post
    Here is an example of major fan parameters (metric) from my Escalade.

    E38_Fans.png
    So you use Tuner pro to manipulate these values? Do you have an example like this of an E78?

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    Quote Originally Posted by GDiddy99 View Post
    So you use Tuner pro to manipulate these values? Do you have an example like this of an E78?
    Yes.
    What i've seen is E38,E39,E40,E67,E78,E92 have almost identical fan control logic with some minor variations, but generally it's like in example above.
    2011 Cadillac Escalade L94 w/LS3 valves and valve springs

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    Quote Originally Posted by verlon View Post
    Yes.
    What i've seen is E38,E39,E40,E67,E78,E92 have almost identical fan control logic with some minor variations, but generally it's like in example above.
    Would you mind sharing your .bin and .xdf you are using so I can check out these parameters?

  12. #12
    Senior Tuner TheMechanic's Avatar
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    Quote Originally Posted by verlon View Post
    Here is an example of major fan parameters (metric) from my Escalade.

    E38_Fans.png
    Any good site to learn how to use TunerPro? I had always thought it was for OBD1 vehicles.

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    Quote Originally Posted by TheMechanic View Post
    Any good site to learn how to use TunerPro? I had always thought it was for OBD1 vehicles.
    I don't know one.
    TunerPro is universal and sufficient in 99% cases.
    2011 Cadillac Escalade L94 w/LS3 valves and valve springs

  14. #14
    Senior Tuner TheMechanic's Avatar
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    Quote Originally Posted by verlon View Post
    I don't know one.
    TunerPro is universal and sufficient in 99% cases.
    What are you using as a dongle/interface? So it works with Gen4 E38's?

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    Quote Originally Posted by TheMechanic View Post
    What are you using as a dongle/interface? So it works with Gen4 E38's?
    CATS obd2 flasher
    2011 Cadillac Escalade L94 w/LS3 valves and valve springs

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    Quote Originally Posted by verlon View Post
    CATS obd2 flasher
    Do you have an XDF for the E78? I can't find one.

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    Quote Originally Posted by GDiddy99 View Post
    Do you have an XDF for the E78? I can't find one.
    No, just for a couple of E38 OS'es.
    2011 Cadillac Escalade L94 w/LS3 valves and valve springs