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DrX
July 20th, 2011, 07:50 AM
I'm logging, and feeling, spark reduction of 17-18* and up to 2 sec duration that appears to be associated with A/C clutch engagement/disengagement. I have logged all spark PIDs and the only one that is active at these times is Total Torque Control Spark Retard (GM.EST_TRQ_DMA). None of the PIDs that are supposed to contribute to this PID are active(trans torque reduction, traction control, brake torque). There is no activity on the A/C Compensation Spark PID.

Does this make sense?
joecar
July 20th, 2011, 08:49 AM
Post log/tune files.
DrX
July 20th, 2011, 09:28 AM
Here are 2 logs(0509- start at frame 5090, and 0510- start around frame 260) of spark PIDs(there are too many to log all at once) and a typical AutoVE log file. I didn't include A/C Comp Spark in the spark PID logs as I included it with the AutoVe log(log 0511 - see frame 2640).
DrX
July 20th, 2011, 10:32 AM
Could this be related to the 50% scaling that has been applied to my current tune so that actual torque reduction is double the target?
joecar
July 24th, 2011, 09:39 PM
I'm still looking at this.

Log GM.STATE00 to see if the AC command coincides with commanded spark.
DrX
July 25th, 2011, 12:11 AM
Thanks Joe. Will do.
DrX
July 29th, 2011, 03:29 PM
Here's a log(big) that includes GM.State00. Didn't turn the A/C on til near the end - start around frame 39700
DrX
August 1st, 2011, 01:36 PM
I disabled B4358 and now there is no retardation of spark at all on A/C clutch engage/disengage.
joecar
August 18th, 2011, 01:14 PM
Ah, now that I look at B4358 it has now become obvious to me :doh2:
DrX
August 18th, 2011, 01:35 PM
Still not sure why this became so aggressive and of such long duration. Possibly somehow related to scaling the tune. Hopefully disabling it doesn't hurt the A/C.
joecar
August 18th, 2011, 01:40 PM
It was there so to overcome any drop in idle speed that activating the A/C compressor would have caused... I don't think you'll have any trouble with that.
DrX
August 19th, 2011, 01:15 AM
From the descriptions it appears to be there to facilitate A/C clutch engagement. It was actually pulling 17-18 degress of timing(decreasing engine output) at highway speeds for 1-2 sec every time the A/C clutch engaged/disengaged. Idle was not a problem. Felt like you were driving with the brakes partially applied every few seconds. I did not notice this before I scaled my VE tables by 50%.

B4369 looks like it limits the spark retard(seems that it references engine vacuum), but I don't see any tables that determine the calculation of the exact amount of spark retard.