E78 controller fans for L96 engine

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02-12-2020
DanSchafer93

2 Attachment(s)

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
03-15-2020
Littlepiston

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.
12-29-2022
laberge

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.
12-29-2022
blindsquirrel

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.
12-30-2022
verlon

Quote:

Originally Posted by DanSchafer93

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.
12-30-2022
GDiddy99

Quote:

Originally Posted by verlon

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?
12-30-2022
verlon

Quote:

Originally Posted by GDiddy99

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.
12-31-2022
verlon

1 Attachment(s)

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

Attachment 127090
12-31-2022
GDiddy99

Quote:

Originally Posted by verlon

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

Attachment 127090

So you use Tuner pro to manipulate these values? Do you have an example like this of an E78?
12-31-2022
verlon

Quote:

Originally Posted by GDiddy99

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.
01-02-2023
GDiddy99

Quote:

Originally Posted by verlon

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?
01-03-2023
TheMechanic

Quote:

Originally Posted by verlon

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

Attachment 127090

Any good site to learn how to use TunerPro? I had always thought it was for OBD1 vehicles.
01-04-2023
verlon

Quote:

Originally Posted by TheMechanic

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.
01-04-2023
TheMechanic

Quote:

Originally Posted by verlon

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?
01-04-2023
verlon

Quote:

Originally Posted by TheMechanic

What are you using as a dongle/interface? So it works with Gen4 E38's?

CATS obd2 flasher
01-05-2023
GDiddy99

Quote:

Originally Posted by verlon

CATS obd2 flasher

Do you have an XDF for the E78? I can't find one.
01-05-2023
verlon

Quote:

Originally Posted by GDiddy99

Do you have an XDF for the E78? I can't find one.

No, just for a couple of E38 OS'es.