What controls EST_XMSN_DMA (Trans Torque Reduction Spark Retard)?

[Mr. P.]

Hello Everyone, been a while I know - this last month I dusted-off EFILive and got back into tuning my truck, and am tackling spark timing issues/questions.... I am trying to dial-in my spark advance table, and eliminate part-throttle KR. I think I am seeing two KR issues, one is light KR under part-throttle driving (1-3 degrees), and the second is major KR (5+ degrees) under sudden load/demand or kickdown. The KR I am seeing is 'spikey' not 'sawtoothed' so I am guessing that this is more burst knock retard (?) rather than detonation, but I am not sure. To get a better idea of my issue, I logged the following PIDS:

GM.KR - zero, except for a single instance of 7-degrees under 1/2-throttle
GM.EST_BTM_DMA - zero the entire log
GM.EST_KRB_DMA - a dozen 'random' spikes of -1 to -3 degrees sprinkled about the whole log
GM.EST_XMSN_DMA - major activity, literally half of the driving was with 18+ degrees of retard

Questions:

What controls EST_XMSN_DMA (Trans Torque Reduction Spark Retard)? The torque management tables in my tune are all zero'd out, where is this activity coming from? I can see GM.SPARK PID affected by EST_XMSN_DMA, but this EST_XMSN_DMA retard is not included in GM.KR PID (I thought it would be?)

(log attached)14324

Vehicle info - 2003 Silverado SS AWD, LQ9 stock with Paxton Novi-1500 @ 10-psi; EFILive COS3.

- Steve.

[joecar]

EST_XMSN_DMA is derived from the Shift Torque Reduction tables (i.e. torque reduction via spark timing during each shift).

As far as I can tell/see, KR includes only retard due to filtered knock event detection.

EST_KRB_DMA is burst knock retard (i.e. predicted retard in anticipation of knock to avoid knock).

EXT_BTM_DMA is brake torque management retard (i.e. during power braking).

[Mr. P.]

EST_XMSN_DMA is derived from the Shift Torque Reduction tables (i.e. torque reduction via spark timing during each shift)...

Okay - that's what I thought. However, each of my Torque Reduction tables is zero'd out (upshift, downshift, and abuse) and all this EST_XMSN_DMA activity is happening during cruise - so where then in my tune is all this spark retard originating from?

- Steve.

[joecar]

Hmmm, interesting, good question.

[Mr. P.]

Here's a screenshot of what I am describing - the second purple trace (labeled TRANS RTD) moves exactly opposite/inverse to the SPARK PID. So this transmission torque reduction PID is retarding ignition timing seemingly when the vehicle is decelerating, or stopped (0-mph)! So in the larger picture I don't think it is costing me MPG or power, it's just odd to see the behavior and I was wondering what was causing it. I know the PCM has lots of logic and parameters for DFCO... is there also maybe some logic at play to modify spark when decelerating?

- Steve.

14334

[TurboCamaro]

I have an 02 SS with a408in it that is pulling timing with EST_XMS_DMA.
I have tried a bunch of things trying to eliminate it including setting B6614 to 0 instead of max.
What am I missing.
Attached is a cal with B6614 at 0 and logs with it at 0 and maxed.
I see there is KR activity with B6614 at 0 as well will look at Burst Knock, etc and see what it is as I have my doubts it is real KR with 8 Deg of advance.


Unfortunately I am still unable to attach log or cal files to the forum so the only file visible is the error message when I try to attach the cal file. Please help.
21157

[joecar]

The pid EST_XMSN_DMA comes from Torque Reduction in the Transmission segment.

~ posted by phone ~

[TurboCamaro]

Hi Joe
Thank you.
I have been through all of the tables in the Transmission Segment and Torque Management in the Engine Section in an effort to eliminate the EST_XMSN_DMA.
Attached is a screen shot of the Trans Segment Abuse settings that I have adjusted as well as a scrn shot of a log showing 20 deg of EST_XMSN_DMA.
Could someone please help with what to modify in order to eliminate the EST_XMSN_DMA from reducing torque.
2115921160
Table B1902 seems to be missing from the calibration. Is this something that EFI Live can help out with or is there a way it can be "added".
21162

I realize it is very difficult to help without seeing the calibration file and a log. But I can't seem to attach log or scan files to a post. Can anyone help with this or let me know where to go for assistance. Here is the error I am getting.
21161
Thanks

[joecar]

Torque Reduction -> Abuse Mode enables when you go from P/N to D/R with substatial RPM's... this does is not what you're seeing.

Look at the tables under Torque Reduction -> Upshift.



~ posted by phone ~

[joecar]

See post #2 here: https://forum.efilive.com/showthread.php?p=38410

start at point 5.

~ posted by phone ~

[TurboCamaro]

Torque Reduction -> Abuse Mode enables when you go crom P/N to D/R with substatial RPM's... this does is not what you're seeing.

Look at the tables under Torque Reduction -> Upshift.



~ posted by phone ~

Thanks Joe
Previously I have left these alone thinking that they are a torque reduction during the shift and not active during "steady state gear". I am using DVT to hold a gear on the dyno.
Which table affects which gear for non shifting accelerations. ie. Is the 2-3 Shift or 3-4 Shift active during a 3rd gear sweep.

Zeroing these Upshift tables doesn't alleviate the EXT_XMSN_DMA activity. Attached are the cal and a log.

Could someone please peruse the cal to see what I may be missing.

I am completely at a loss with this thing.
I have tried all I can think of including B6614 setting from 0 to max or 866.
Please see most recent cal file and log. Please assist.

[TurboCamaro]

See post #2 here: https://forum.efilive.com/showthread.php?p=38410

start at point 5.

~ posted by phone ~

Thank you this is how I was attaching.
Not sure what happened over the night however I see even my earlier posts have the files attached.
Thanks

[joecar]

Thanks Joe
Previously I have left these alone thinking that they are a torque reduction during the shift and not active during "steady state gear". I am using DVT to hold a gear on the dyno.
Which table affects which gear for non shifting accelerations. ie. Is the 2-3 Shift or 3-4 Shift active during a 3rd gear sweep.

Zeroing these Upshift tables doesn't alleviate the EXT_XMSN_DMA activity. Attached are the cal and a log.
2116921170
Could someone please peruse the cal to see what I may be missing.

I am completely at a loss with this thing.
I have tried all I can think of including B6614 setting from 0 to max or 866.
Please see most recent cal file and log. Please assist.
2117221171I'll look thru your files... hmm, sounds like something else is going on...

[joecar]

Thank you this is how I was attaching.
Not sure what happened over the night however I see even my earlier posts have the files attached.
ThanksDo you click Add Files (at the upper right)...?

[TurboCamaro]

I'll look thru your files... hmm, sounds like something else is going on...
Thanks Joe
I appreciate it.
This thing is down about 100hp from where it should be.

[TurboCamaro]

It seems the solution to the EXT_XMSN_DMA activity is to ignore it. Using the dyno I determined any KR activity stemming from the Knock Sensors to be false knock and detuned the Knock Sensors allowing increase of timing and associated power increase. As the timing increased and power increased the EXT_XMSN_DMA activity disappeared.

[joecar]

Thanks for posting back what you see.