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Thread: NAG1/A580 Part Throttle Shift Scheduling Table Tuning

  1. #41
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    I wonder the FCA carried over the Mercedes logic to reset the adaptive shifting?

    http://www.mercedesmedic.com/reset-m...-instructions/

    Edit: Nope, plus there is an option to do that from the scanner software.

    As a note I have got the NAG1 to stop downshifting in autostick.

    WOT = Enable
    Auto Upshift = Enable
    Autostick WOT = Enable
    Perf Driving = Disable

    Not sure if Auto Upshift was necessary but I thought why not. But WOT and Autostick WOT need to be enabled to stop the trans downshifting at 98% throttle (transmission throttle, not the same as PCM throttle).
    Last edited by xennex; 08-15-2020 at 06:02 PM.

  2. #42
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    Had another feeble attempt at getting these PT shifts predictable by disabling and zeroing out anything that had to with "trans torque adapts" on both the trans and engine side of things.
    After I wrote the tune to the ECU and TCM I reset all trans adaptives and did a EGS53 init.

    This did not result in any noticeable change in how the trans shifted. In the datalog those upshift/downshift speed offsets were still active and messing with the PT shift scheduling......

    Pretty much out of ideas here with the trans parameters that are accessible via HPT.

  3. #43
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    Quote Originally Posted by HaasExp View Post
    Had another feeble attempt at getting these PT shifts predictable by disabling and zeroing out anything that had to with "trans torque adapts" on both the trans and engine side of things.
    After I wrote the tune to the ECU and TCM I reset all trans adaptives and did a EGS53 init.

    This did not result in any noticeable change in how the trans shifted. In the datalog those upshift/downshift speed offsets were still active and messing with the PT shift scheduling......

    Pretty much out of ideas here with the trans parameters that are accessible via HPT.
    I have seen reports that using the EGS52/EGS53 Init function basically reverts the TCM back to stock. I don't understand how this is possible, but it might be worth re-reading your TCM now that you've used that function and see if the changes you had made are still present or not.

  4. #44
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    Cheers B00STJUNKY ill check it out.

    Im becoming more convinced that these shift speed offsets are some form of adaptive but at this stage it seems we dont have any control over them.

  5. #45
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    HaasExp you have tuned the engine ?

  6. #46
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    Time for a bit of an update.

    I've been doing some supercharger maintenance (removed) so have been driving the vehicle around on the factory stock tune, that is the factory engine and TCM tune.

    I can confirm that this weirdness with the shifts still occurs on the factory tune! I've also datalogged a few other 3.6/NAG1 Wranglers and they also have the same thing happening, where the "upshift/downshift speed offset" modifies the actual shift speeds in the normal shift scheduling table.

    I can also confirm that doing a EGS53 Init does not revert the TCM back to stock for those wondering.

    Observing the behavior of this "speed offset" variable seems to indicate that it is affected/controlled by vehicle acceleration rate, pedal rate, gear change, brake use etc. This logically seems to point to factors like the "term coefficients" and "decay divisor" parameters under the "Performance Driving Factor". According to some patents these sort of parameters are employed to provide advanced shifting strategies to help with gear anti-hunt and predictive shifts based on the vehicles/drivers behavior.

    However, I have messed around with these parameters alot (large values, small values, inbetween and combinations of everything under the sun) and the do not seem to effect the "offset speed" at all

    So it begs the following questions:

    1. Are the another set of un-mapped parameters that control this offset??
    2. Is HP tuners writing the correct values to the "term coefficients" and "decay divisors"?

  7. #47
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    Quote Originally Posted by HaasExp View Post
    I can also confirm that doing a EGS53 Init does not revert the TCM back to stock for those wondering

    Thanks for checking on this and updating the thread. This notion always seemed strange to me, but I haven't ever tried disproving it.

  8. #48
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    I was fighting with this on a customer vehicle quite some time ago. I decided that there must be a table or modifier that we don't have access to. I've discussed with tech at HP, a few other tuners, and a Chrysler tech that is semi-knowledgable. No one has been able to point me to a solution. As a band-aid I've just modified the minimum shift tables to get a more favorable shift point. It is definitely not perfect, but is much better than stock.

  9. #49
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    Quote Originally Posted by raceplayhavefun View Post
    I was fighting with this on a customer vehicle quite some time ago. I decided that there must be a table or modifier that we don't have access to. I've discussed with tech at HP, a few other tuners, and a Chrysler tech that is semi-knowledgable. No one has been able to point me to a solution. As a band-aid I've just modified the minimum shift tables to get a more favorable shift point. It is definitely not perfect, but is much better than stock.
    Cheers for chiming in raceplay. There are definitely some critical parameters missing here that control all of this in the background. The part-throttle shift tables do seem to be the minimum OSS that the upshift can occur as you also have concluded.

    I have applied the same bandaid as you, particularly on the 3-4 upshift at around ~30-40%. I just dropped the shift speeds significantly to counteract the large upshift offset speeds that usually occur. Works ok but as the upshift offset speed does vary depending on vehicle speed/acceleration/pedal rate it can have some very low values and cause upshifts to occur to low also.

  10. #50
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    I know it has been a long tme, just wondering if you ever resolved the issue. I'm having this problem now. Do you have a tune file for the best you were able to get it? I'd love to compare what I have to it. Thanks.

  11. #51
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    Quote Originally Posted by mattshake9451 View Post
    I know it has been a long tme, just wondering if you ever resolved the issue. I'm having this problem now. Do you have a tune file for the best you were able to get it? I'd love to compare what I have to it. Thanks.
    It's not perfect but this is how much i reduced the shift speeds to get the shifts to not hang as much between the 3-4 upshift under light/medium throttle conditions. Note that this is on a Rubicon Unlimited with 4.10's and 35's
    trans3-4.JPG

  12. #52
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    What?s the chances one of you could help me with my tune?
    By the prickle of my thumb something wicked this way comes!2008 Chrysler 300c! 2013 heads/220/230 comp cam/LTheaders/FTI 2600 stall converter.

  13. #53
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    I am new here so first post. I have a NAG1 in my Magnum SRT. While researching learning materials for this tranny I found a cool video at the tuning school and a spread sheet from they download course materials-> dodge transmission (these are free), that will take your parameters and then calculate the values to put in your tune. I am going to try this out on my Magnum this week-end and see how its goes. This will be the first tune I put into my car with my new HP tuner. Just have to purchase some credits for it. And make sure I back up my stock tune in several places.

    My reason for wanting to tune my trans is after I put in my Whipple, the new horse power made my car handle much different in the shifting. My going WOT all the time does not help lol. Additionally my auto stick does not shift automatically but hits the rev limiter. My old RT magnum had this enabled and I liked it better when it would shift for me if I went too high.

  14. #54
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    I have been reading this thread. I am about to start changing some shift points on a 2012 JK. I am not anticipating having some of the same issues as the truck is otherwise stock. But maybe someone can answer this question for me. On the downshift tables the same data labels are used multiple times however the shift points are different. For example TPS %: 0,10,37,76,85,85,95,95,100 My assumption is it must have to do with the direction of throttle input ramping up from 76 to 85 vs coming down from 95 to 85 ?

    Thanks

  15. #55
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    I was going to start looking into this but i see @HassExp have tried his very best with no luck. Damn it. I'm just glad i found this post as i was going to start playing with what i thought was the obvious, lowering the part throttle upshift table for the 2-3 shift. I sold my 13 Jeep JKU years ago but i picked another 18 JKU couple of months ago and it wasn't until today that i'm able to tune it.

    In my case my upshifts have zero issues doing what the're are supposed to do if i'm driving on any flat road. the moment i go uphill is when the 2-3 hangs forever unless i release the throttle, maybe 3-4 works the same but i haven't paid enough attention. I was going to leave the tune stock but the 2-3 delay bug the crap put of me and i thought it was going to be an easy fix

    My 13 did the same thing as well, no issues with the upshifts on flat roads, but delayed 2-3 upshift when going uphill.
    If i shift with the autostick everything works correctly and that was the case even in stock trim. That's was in fact my fix for this issue when going uphill, but again i paid for the licenses and the unlocking thinking i was going to be able to fix this quickly.

  16. #56
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    According to this article, the shift schedule operates under these parameters
    http://www.sequentialtaillights.com/dodge/TCM-NAG1.htm

    SHIFT SCHEDULES:
    The basic shift schedule includes up and downshifts for all five gears. The TCM adapts the shift program according to driving style, accelerator pedal position and deviation of vehicle speed. Influencing factors are:

    1. Road Conditions.
    2. Incline, Decline and Altitude.
    3. Trailer Operation, Loading.
    4. Engine Coolant Temperature.
    5. Cruise Control Operation.
    6. Sporty Driving Style.
    7. Low and High ATF Temperature.

    If we can get the boys from HPT to look into the bits maybe they can correlate these parameters in the trans logic and give us what we need ?

    Also something intersting to read if resetting the trans adapts:

    TCM ADAPTATION - NAG1 Only
    The adaptation procedure requires the use of the appropriate scan tool. This program allows the electronic transmission system to re-calibrate itself. This will provide the proper baseline transmission operation. The adaptation procedure should be performed if any of the following procedures are performed:

    1. Transmission Assembly Replacement
    2. Transmission Control Module Replacement
    3. Clutch Plate and/or Seal Replacement
    4. Electro-hydraulic Unit Replacement or Recondition

    1. With the scan tool, reset the Transmission adaptive's. Resetting adaptive's will set the adaptive's to factory settings.

    NOTE:
    For Upshift adaptation, the Transmission temperature must be greater than 60?C (140?F) and less than 100?C (212?F). Failure to stay within these temperature ranges will void this procedure.

    2. Drive the vehicle until the transmission temperature is in the specified range.

    3. Perform 4 to 5 coast downs from 5th to 4th gear and then 4th to 3rd gear.

    4. From a stop, moderately accelerate the vehicle and obtain all forward gear ranges while keeping the Engine RPM below 1800 RPM. Repeat this procedure 4 to 5 times.

    5. Obtaining 5th gear may be difficult at 1800 RPM. Allow transmission to shift into 5th gear at a higher RPM then lower the RPM to 1800 and perform manual shifts between 4th and 5th gears using the shift lever.

    6. The TCM will store the adaptive's every 10 minutes. After completion of the adaptation procedure make sure the vehicle stays running for at least 10 minutes.

    7. It is possible to manually store the adaptive's under the 10 minute time frame using the scan tool Store Adaptive's procedure.
    Last edited by bluegoat06; 08-13-2021 at 11:50 PM.

  17. #57
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    Quote Originally Posted by clinter36 View Post
    On the downshift tables the same data labels are used multiple times however the shift points are different. For example TPS %: 0,10,37,76,85,85,95,95,100 ?
    This may be a scaling issue from HPT. I spent a bit of time discussing the NAG1 with Yeti ChipTuning and he showed me the axis values as read from Winols hex editor. From Winols these TPS% breakpoints are very different, yet much more logical for both the upshift and downshift tables compared to what HPT shows.

  18. #58
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    Quote Originally Posted by bluegoat06 View Post
    In my case my upshifts have zero issues doing what the're are supposed to do if i'm driving on any flat road. the moment i go uphill is when the 2-3 hangs forever unless i release the throttle, maybe 3-4 works the same but i haven't paid enough attention. I was going to leave the tune stock but the 2-3 delay bug the crap put of me and i thought it was going to be an easy fix

    My 13 did the same thing as well, no issues with the upshifts on flat roads, but delayed 2-3 upshift when going uphill.
    Thanks for chiming in bluegoat.

    Yes you have clearly summarized the issue. The algorithm detects an incline (or what it thinks is an incline, most likely due to pedal position/speed/acceleration etc) and delays the shift to give more power. However, this delay is just far too great which leaves it hanging on to the gear and high rpms for seemingly no reason. It could easily pull the next gear in these situations.
    I've come across http://www.sequentialtaillights.com/dodge/TCM-NAG1.htm before and looked into the parameters we had available in HPT that deal with lateral acceleration, pedal, braking etc etc. I messed heavily with these and did not notice an ounce of change. Thus I concluded that there must be another set of similar variables that HPT have not yet mapped out that control this.
    I reached out to HPT and gave them as much info and data as I possibly could but they don't seem to deal with finding new parameters and variables.

    Anyway, in short form:

    If you log the "Upshift Speed Offset" and it's not zero, then the shifting speed will not = whats in the PT shift tables. It will be delayed and will not upshift until the OSS + Upshift Speed Offset >= whats in your PT shift scheduling table.
    Until we have control over this speed offset then the PT shift scheduling table will only dictate the MINIMUM OSS that the shift will occur at.

  19. #59
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    Wish I had read this this morning. I ordered a MPVI2+ and 2 credits this morning to try and lower my shift points on my 2014 JKU Rubi. Slight uphills and 2 to 3 wants to hang on till about 4800ish rpms when I can bump it at around 3600 and it still pulls fine uphill. Already got the email that order is on the way!

    Anything you found with all the research you did that would help my stock engine with this shifting? I see y'all running SCs. And can I have my fan come on about 10 degrees sooner?

  20. #60
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    I've been away from the forum for some time, but have just spent a week in Colorado and the trans shifting is driving me nuts. It's getting worse than the typical never up-shift problem; I seem to spend most of my time in manual mode fighting the transmission. Recently I have noticed that the use of cruise control will change the shift points quite markedly, and if you use the manual shift too much the TCM will start to do very odd things. eg shifting 3rd to 4th and then immediately to 2nd. There is a correlation to high ECT too, and cruise control makes things worse.
    I'm fairly good with binary analysis, have Winols etc. I'm fairly sure there are many tables that HPTuners does not have. Working in this direction would good, but I think the TCM binary is just the EEPROM/Flash data and not the code as well..