How does Gen III Torque Management work

[weinerschizel]

I need to be upfront, my question is NOT HOW TO REMOVE Torque Management. I already know how to dial it back.

I need to understand what TM is monitoring that causes it to pull timing. I want to log those same PIDs and see how TM is working.

BACKGROUND: I have a 2001 Chevy Tahoe, believe it's a P01 Gen III Computer (possibly P59?). I have a built 4L60E and 6.0L with mild cam. I'm using baseline 5.3L tune, updating VE and MAF calibration. During some of my data runs it's pulling as much as 30 degrees of timing. I have also attached my latest tune "03 RUn 05 Final". It is setup to run / tune VE. Running MAF / MAP doesn't seem to make a difference in TM behavior.

TM Waveform from "Run 10.hpl"
tm MAF 10.jpg

TM Waveform "03 RUn 04.hpl"
TMRUN4.jpg

[TheMechanic]

nnn.JPG
Make the 1 a ZERO on Brake TqMgt
Be prepared to break that 4L60e

[weinerschizel]

I'm sorry, I made a typo. I know how to remove torque management already. I need to know what PIDs to monitor so I can adjust it appropriately. I also have a built 4L60E specifically for my project. I designed / spec'd the parts to handle the power & torque. I want to know how to make an informed decision on adjusting Torque Management instead of deleting it or blindly dialing it back.

[kingtal0n]

There is a torque management advance PID you can monitor

however in my experience it will hit or miss in the log. Half the time I Don't see it, sometimes I do, sometimes it only catches half of it.

I go by feel now. I play with the torque management reductions until the car shifts smooth and feels good. You can just tell if something is too harsh or the tire spin is slowing you down. Then whatever it is is whatever it is.

Not saying that is the correct way, but its my way

[eXo3901]

I posted some patents in this thread. It?s gives some decent insight into the process.
https://forum.hptuners.com/showthrea...agement-Issues

[weinerschizel]

Thanks @TheMechanic, #kingtalOn, & @eXo3901 for the pointers.

@eXo3901 I read the post. Good stuff. Made me realize, I did put in a higher stall Torque Converter, 2600 RPM Circle D. However, my issues don't seem to coincide necessarily correlate with gear changes. That said, maybe there's some transmission tuning I'm in need of doing aggravating the issue.

I have a mostly stock spec transmission, granted upgraded parts, few Sonnax goodies, etc. The only thing that isn't factory spec is the torque converter in my 4L60E build. Not sure if that could cause Torque Management to act up?

DARN this guy explains my problem in video but not how to fix it haha Guess I need to buy his class?

https://www.youtube.com/watch?v=VIUttNQKLsI

[weinerschizel]

Noticing a weird anomaly in "03 Run 04.hpl" log file. The transmission torque management timing pulls are not taking place when it's shifting. Denoted by Yellow Arrows. Next I have a couple points where the gear seems fluctuate, denoted by yellow circles.

tmGearShift.jpg

I think I need to go in and monitor a bunch of PIDs to view what's going on in the transmission then try and correlate them with the TM timing pulls. Anybody have a good list I can look at?

[kingtal0n]

You can use the search feature to find all channels with the words "timing" attached. There are like 10 of them.

Heres my gen3 file and some layouts attached, it might load the timing PID I used for your scanner, I'm not sure
https://forum.hptuners.com/showthrea...l=1#post686802

[eXo3901]

Noticing a weird anomaly in "03 Run 04.hpl" log file. The transmission torque management timing pulls are not taking place when it's shifting. Denoted by Yellow Arrows. Next I have a couple points where the gear seems fluctuate, denoted by yellow circles.

tmGearShift.jpg

I think I need to go in and monitor a bunch of PIDs to view what's going on in the transmission then try and correlate them with the TM timing pulls. Anybody have a good list I can look at?

Those random spikes could be the A/C kicking on/off. Not saying that is your issue or the issue in the video. Just something that could be ruled out easily and help narrow the search.

[TheMechanic]

I always start with BlueCat. Seems to get all the things I want to change pretty close if not perfect right out of the box. You could use it and then do the compare function to see all the changes and adjust accordingly.

[weinerschizel]

kingtal0n - I will search for the timing PIDs and add them.

eXo3901 - VERY helpful. I will do runs with AC off, although it's DAMN hot here right now haha

TheMechanic - what is BlueCat?

My plan it so turn down or off the superfluous Torque Management stuff...

- I will turn off traction control (not sure if my truck ever calls that? I have no traction control button).
- Dial back engine TM
- Disable TM under braking

But leave the transmission stuff. However, I need to log the PIDS for the transmission as well along with the timing pull parameter. I'm not sure how the transmission TM works. The screen capture I made in post #7 really threw me for a curve. It showed timing pulled prior to gear change so made me wonder when exactly does timing get pulled?

- When TCC clutch locks up?
- When solenoids select valve for gear?
- When pressure stabilize in valve body?.

I want to verify I didn't mess something up timing wise that needs tuned when I build my transmission.

[kingtal0n]

The common conception (at least for me) Is that the ECU watches the rpm drop or input shaft speed sensor (I am not sure which, or when, yet) in conjunction with output shaft or converter slip to determine when the actual shift is occurring, and finishes. And it will reduce timing at the exact instant a shift occurs using this data IF it can accurately determine the shift start and end. Which doesn't seem to always be the case.

The amount of timing is in the engine torque management pages iirc, there are two main tables. One tells the ECU how much timing to pull for a given desired reduction. The other table tells the ECU how much torque is reduced for a given reduction. They seem redundant but they are absolutely NOT the same thing. In my experience the table which tells the ECU how much torque is reduced can really screw your transmission up because it can inaccurately estimate torque reduction and cause a loss of shift pressure. For example I think the factory table says that pulling 10* of timing is worth like 30% or 50% of torque reduction, so at WOT the ECU thinks the engine torque is half of what it really is, resulting with a force motor current lookup value inadequate shift pressure, causing a transmission slippage. One good slip and pooof goodbye trans. So to fix this I set the table so that even with massive reduction in timing the amount of torque reduction is very low, like 5% torque reduced even for 20* of timing reduction or whatever. This allows your shift pressure to stay nice and high even when alot of timing is being pulled out during a shift, which is nice because torque reduction preserves the transmission and keeps the tire spin down.
The other table not so big a deal, but still I modify it. I increased the amount of timing reduction for a given commanded torque reduction , so I can command very little torque management (like 9% to 12%) and get a massive reduction in timing. This also helps with the other table because you command less torque reduction means the table has even less 'guessed' torque reduction, it helps both ways.

I've read that modifying those tables can negatively influence other behaviors like engine friction torque or predicted torque from other reason/sources. So caveat emptor, don't blindly do as I do without being careful reading and considering things. I am just not afraid to burn a trans in experimentation because mine is easy to rebuild and spare parts are easy to get. I actually enjoy going through the 4l80e transmission its so simple compared to a 4l60e my god what a night and day. 4l60e you had better have some really good snap ring pliers and several spacial tools. The 80e well, you can almost remove the snaps with bare hands and you can get by using electrical tape and a $20 amazon compressor tool.

[weinerschizel]

I logged data per Post #11. Dramatically cleaned up TM. I only saw TM on shifts until I turned on the AC.

However, my torque loss event persisted. I captured the event in a log file (attached) with screen capture below. I felt it going up a hill from a standstill. Torque was building then just cut out. Engine Revs didn't climb... however, I let off the gas shortly after event. Then I turned on the AC (signaled by TM pulling timing shortly after event).

TORQUE LOSS EVENT.jpg

A little more info from my original post. I hand built my 4L60E myself, consulting an experienced 4L60E builder (100+ rebuilds most for hotrods including his). I did mail off the input drum for him to seal input shaft, install Sonnax reinforcement, and assemble with top shelf clutches. The whole build took me about 6 months after work of study and putting things together.

I didn't modify the valve body. It was purchased from Teal Automotive, a transmission scrapyard, with a ~2005 casting number. I don't know the valve body's history, although casting was impeccable, looked like it had just been machined. I disassembled the valve body and inspected everything as best as possible (I don't have a vacuum tester). Then put back together with Sonnax pin less accumulator, new force motor, solenoids, new screens, and plastic Sonnax check balls. My first thoughts go to the valve body as it was only part I couldn't fully validate and didn't receive a full rebuild.

[Matt Vardaman]

Noticing a weird anomaly in "03 Run 04.hpl" log file. The transmission torque management timing pulls are not taking place when it's shifting. Denoted by Yellow Arrows. Next I have a couple points where the gear seems fluctuate, denoted by yellow circles.

tmGearShift.jpg

I think I need to go in and monitor a bunch of PIDs to view what's going on in the transmission then try and correlate them with the TM timing pulls. Anybody have a good list I can look at?

Were you running the AC? that's what it looks like. When my compressor cycles with the AC on low/fan speed 1/2 I would get random Tm timing dips. I believe it has to do with the AC bump torque spark smoothing and AC TM. It was in my case.

edit: I logged the AC active flag to verify.

Nevermind, I see you covered AC

[weinerschizel]

I only turned on AC to highlight file after adverse event took place.

I suspect my issue maybe unrelated to Torque Management all together.

I think I'll start a new thread.

[weinerschizel]

I started a new thread HERE Trying to figure out what I'm looking at when logging data for transmission.

[dhoagland]

Might be nothing, but just like my last reply in your other thread where I saw TPS dip hard during a shift.
This shot is what appears to be steady state driving. All of your airflow, spark, torque are following the "non steady TPS signal

[weinerschizel]

Yeah I did some more datalogging this morning. I may be a dumb a$$. I was oscillating the throttle too much. Couldn't make heads or tails of of what was going on in my previous data logs. This morning I forced gears with VCM Scanner as well as manually with column shifter. It was holding the gear with one exception which I need to go back and review. I also drove normally without twitching the throttle peddal.

I think 99% of my issues was my wild pumping of the throttle. I got into habit of doing that as I it's so hard to get all the cells in the VE table. Probably isn't good practice there either.

[weinerschizel]

I think I'm on track to figuring it out. Everything is likely result of operator error (too much throttle flocculation - I have cable throttle) and poor tune for my 4L60E. I have a mildly cammed LQ9 build running in baseline tune from 5.3L truck without any updates to the transmission in the tune.

I've programmed VE, MAF, and few odds and ends to get engine running well. However, I think there's some quirks left in my tune on the transmission side. Studying up on it now.