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B8 A5 3.0TDI torque limiting before shifts

Tjaart Aug 11, 2017

  1. Tjaart

    Tjaart New Member

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    Hi All. I am in need for some advice/input as to why my car is acting the way it is.
    2010 Audi A5 3.0 TDI Stronic, CCWA and DL501

    The car is limiting torque at full throttle and high rpm just before shifting (worse in manual mode). This only happens in sport mode and for gear 1, 2 and 3 only. Gear 4 and 5 shift fine. (gear 6 and 7 not tested). In Drive all shifts are fine under full throttle.

    The engine has a mild tune, currently sitting at 170kW/228Hp and 544Nm (wheel figures)
    With VCDS, no engine or transmission errors.
    The gearbox is running the updated ASAM file so the TSB/TPI for lagging when cold should not be an issue (version A02087). Car is going the Audi on Monday just in case there is an update available.

    I though the gearbox needs software to sort the issue, but it has not. The tuner tried 3 different brands of ECU and TCU software and they all are doing the same. So either the software from 3 vendors are wrong, or there is some sensor or mechanical problem causing this.

    I also removed the ESP fuse to check if that is not causing the limitation, but no luck.
    I did a 5th gear pull and EGT spiked at 868 degrees Celsius.

    Any advice of where to look or what it can be will be appreciated.

    Mod list include:
    DPF cleaned out
    Air filter box flap removed (stock filter)
    230 x 550 x 65 Intercooler

    Below is a picture of a VCDS logged run in sport mode. Started in gear 3, full throttle until automatically shifted to 5th.

    Sport run gear 3 to 5.jpg
     
  2. Tjaart

    Tjaart New Member

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    Here is the run in drive, gear 2 to 5:
    Drive run gear 2 to 5.jpg
     
  3. desertstorm

    desertstorm Moderator Staff Member Moderator VCDS Map User quattro Audi A4 Audi Avant Owner Group TDi

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    The standard map starts cutting fuel at 850 degrees EGT and it is very aggressive. Feels like somebody has stood on the brakes. If the tuner hasn't modified these EGT protection maps then that could be your issue. I presume it's OK in drive as the engine only revs just over 4000 RPM before it changes gear so EGT's won't be as bad. In my Manual car you could only feel the effects of it in higher gears though where the load was sustained.
    But there are also many limiters in the engine map and I presume gearbox map as well that may be causing your issue.
    @bobby singh is your man.
     
  4. bobby singh

    bobby singh BSR VCDS Map User quattro Audi A4 TDi

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    You need to log egt factor
    Torq limitation based on EGT
    On all DL501's I increase the torq limiter - there are many tunable maps like quicker shift times etc, torque reduction between gear change.
    But you always want torq reduction between gear changes for obvious reasons
     
  5. bobby singh

    bobby singh BSR VCDS Map User quattro Audi A4 TDi

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    What version file do you have on the gearbox controller? I can check if there is a update available
     
  6. Tjaart

    Tjaart New Member

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    Thanks for the replies. It makes sense hitting the EGT limiter. I will do some logs tomorrow to confirm or rule out.
    I only logged EGT on the 5th gear pull, but I can see the EGT starts shooting up in the higher rpm range. I don't feel any aggressive fuel cutting in 4th and 5th gear, but looking at this graph it seems some less aggressive limitation is still happening.
    5th gear EGT.jpg

    Agreed, the torque limitation is quite harsh.


    That would be very kind, thanks Bobby. Herewith the Gearbox info:
    Thursday,10,August,2017,18:24:13:32269
    VCDS Version: Release 17.1.3 (x64)
    Address 02: Auto Trans
    Control Module Part Number: 8K1 927 156 AB
    Component and/or Version: 0B5 30 TDIRdW H04 0003
    Software Coding: 000001
    Work Shop Code: WSC 51064
    VCID: 75E703DDD4BF3BE9CA-8020

    Advanced Identification/FAZIT
    Serial number: 0000000592
    Identification: TFK-030
    Revision: --H04---
    Date: 19.09.13
    Manufacturer number: 0902
    Test stand number: 0592
    Flash Status
    Programming Attempts(application): 1/1
    Successful Attempts(application): 1/1
    Programming Status: 00000000
    Flash Date: 13.10.20
    Flash Date: 0000.00.00
    Flash Tool Code: 00000 000 00000
    Software
    UDS: 01.02.13
    ISO15765: 01.02.16
    CAN: 01.07.00
    HiSpd Net: 01.06.00
    Misc.
    Hardware number: 0B5 927 156 E
    Workshop System Name: J217
    ASAM Dataset: EV_TCMDL501
    ASAM Dataset Revision: A02087
    Car Info
    Chassis Number: WAUZZZ8TXAA064488
    VCDS Info:
    VCID: 75E703DDD4BF3BE9CA-8020
    Labels: 0B5-927-156.clb
    ROD: EV_TCMDL501.rod
     
  7. Tjaart

    Tjaart New Member

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    I had two logging sessions and this is what I found:

    Session 1
    I logged: Governing factor exhaust temp, Limitation: torque and rpm
    I drove in dynamic and did 2 runs: 1) LC till 4 gear 2) LC till 5 Gear
    Governing factor exhaust temp was 1 throughout the session. Torque limitation still happened

    Session 2
    Engine torque, limitation: torque, EGT and RPM
    The car has Drive select, so Dynamic mode selected, manual mode engaged and left for it to shift on its own. Here is a graph of one part of the run, gear 2 - 4.
    RPM vs EGT.jpg

    Max EGT for the whole session was 658 degrees. The limiting is the worst in manual mode. Limiting to 45Nm, it is brutal.

    Some extra info; intake temps maxed at ~30 degrees, ambient was 16 degrees.

    From this I don't think the limitation is due to EGT. The session included a full 4th gear pull, at the EGT did not even pass 700 degrees. If "Gearbox control unit limiting torque" is the only parameter that influences the ECU torque, then it only interrupts during shift and not before. Thus it seems to me the code causing all this should be in the ECU?
     
  8. Tjaart

    Tjaart New Member

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    Some more info:
    Auto vs Dynamic.jpg
    The max Fuel being injected are the same for both Auto and Dynamic (64 mg/stroke), boost levels same as well (overlooking the spikes). Looking at the graph, it almost looks like the limiters are adjusted for Auto, but not for Dynamic. Does a car with Audi Drive select have additional maps that the tuners may have missed?
     
  9. Tjaart

    Tjaart New Member

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    Some feedback: a local gearbox specialist determined that 2 updates are available for the gearbox. It is on version 0003 currently, 0005 is available.
    I will report back next week after the update has been applied.

    Hopefully it sorts out this torque limitation issue
     
  10. Tjaart

    Tjaart New Member

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    Torque limitation still present. :disappointed:

    The gearbox feels.... well, more optimized. Slow speed response is better. So that is at least worth the update cost :sunglasses:

    Next steps: Car will go back to tuner and spend a week for logging and fault finding.
     
  11. Tjaart

    Tjaart New Member

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    Okay so problem fixed. I ended up going to a different tuner.

    He found parts of the ECU file missing, like the whole DTC table was deleted. So he flashed a stock file and built it up from there.

    We never had to touch the TCU. Now with my school fees paid, I can better enjoy the car.
     
  12. desertstorm

    desertstorm Moderator Staff Member Moderator VCDS Map User quattro Audi A4 Audi Avant Owner Group TDi

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    Well that's one way of tuning a car I suppose by deleting large chunks of the existing map that might be getting in the way :) .
    Glad you have it sorted, It's well worth while paying a bit extra or even travelling a bit to find somebody who can do the job properly.
     

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