Wave-like acceleration at medium speed, MKB BRE

Hi,

Audi A6 4F, 2.0 TDI, Engine Identification BRE. Born in 2007,
LMM (Hitachi) is being replaced because the diagnostic memory indicated a fault.

The testing of the old LMM should only have been possible with an oscilloscope device, which would have cost €90, based on the knowledge available at the time.
The new LMM cost 55 €. It is rumored that the Hitachi was allegedly installed in the Audi.

Error occurs after installation but reappears with a
"unplausible signal at LMM" = same error message.

The appearance of the yellow engine warning light does not coincide in time with the appearance of the wave-like acceleration.
When the wave-like acceleration occurs, starting at 50-70 degrees, and is not present in the cold state, there is a loss of power. This is the "camel driver" phenomenon that is often discussed here, and it is noticeable.

After another run, the irregular running disappears.
Today, I was able to get the car running again with my wife's help, using VCDS.
I hope that I have included all the relevant MWBs.
I also had the "Actual" and "Target" values for the AGR, but I couldn't find the corresponding air mass flow target. (?)

Since I'm not a professional mechanic, and I don't understand all the comments from the decorators here, I still hope that someone will tell me what information I'm missing, or if I can provide my CSV file. I can already start working on the file.

Thank you.

[Translating...]

Hallo,

am wahrscheinlichsten ist Mengenbegrenzung aufgrund Luftmasse (LMM), allgemeiner Kraftstoffmangel (besonders bei Vollgas spürbar) und eine Begrenzung aufgrund zu hoher vermeintlicher Abgastemperatur.

Ich würde zuerst LMM Werte prüfen, dann die Mengenbegrenzungen schauen und falls diese ok sind, mit der Kraftstoffversorgung weiter machen.

Viele Grüsse, Rainer

Hi,

I understand the answer as:

The log values with VCDs for LMM-Is, speed, accelerator pedal (driver's preference), etc., should be re-created correctly using MWB 8 and 10, and the CSV file should be as verschandeln as possible, with irrelevant data made visible.
This is not about measuring LMMs with a multimeter.
Is that correct?
And during the log run, it would be desirable to also give full throttle in the third gear, even when the RPMs are above 1300.
And all of this should happen, specifically when the error occurs.

And is Trübungsbegrenzung the same as the smoke control limit in the MWB? (Nm)?
Or is this the torque limit?
Greetings
Ronald

[Translating...]

Hallo

Quote:

Die log Werte mit vcds für LMM-Ist und Drehzahl, Gaspedal ( Fahrerwunsch) usw. sollen mit MWB 8 und 10 noch einmal korrekt erstellt werden und die csv Datei möglichst bereinigt um Datenmüll zur Ansicht gebracht werden. Von Messen des LMM mit Multimeter ist nicht die Rede. Soweit richtig ? Und bei der log Fahrt wäre es wünschenswert, dass im dritten Gang über 1300 rpm auch mal Vollgas gegeben wird. Und das alles möglichst dann, wenn der Fehler auftritt. Und ist Trübungsbegrenzung das, was im MWB Rauchbegrenzung heisst ? (Nm)?

ja

Quote:

Oder ist das die Drehmomentbegrenzung ?

= Begrenzung über Getriebemoment, diese sollte bei Vollgas immer der niedrigste Wert der Begrenzungen sein.

Viele Grüsse, Rainer

Hi,

I tried to analyze the log file LOG-001-080-010-xx_140424, but unfortunately, it was not possible to accelerate fully during the trip, which probably makes the analysis more difficult.
Nevertheless, "fortunately," the yellow engine warning light illuminated during the drive, -and, according to my memory, repeatedly - while driving at higher speeds on the highway.
Therefore, I attempted to create a diagram from approximately the start of the highway journey using Excel.

It is important to note that there was no camel-driving effect experienced when the lamp was lit.
And, the reading of the error log, which points to a time three days before the flight, also showed no evidence of a "camel effect." The fault memory indicates a nonsensical signal from the LMM.

If my data is not yet suitable for analysis, please reply.

The PNG images of the screenshots reveal that unfortunately, the line for the second MWB (010) was not clicked.
However, everything was correctly written in the CSV file.

[Translating...]

Die Bildchen sind nutzlos. Schau' doch einfach ob bei Vollgas die Begrenzung über Getriebemoment die niedrigste ist.

Dachte eigentlich, das hätte ich schon geschrieben.

Und wenn der LMM im Fehlerspeicher ist, da dann poste den halt. Was'n sonst?

Hi,

I hope that this file can be used effectively.
It is the CSV file from Ross-Tech, which has been converted to an XLSX file using the Ross-Tech tool.

If I read it correctly, at full throttle, the torque limit is at least twice the lowest torque value.

Once, the value under full throttle is higher than the value of the smoke limit.
But what does that mean?

Since my car has an automatic transmission, it shifts from the 3rd to the 4th gear automatically after a short time when the engine speed is high and the accelerator is fully depressed.
I believe - and also hope - that it won't negatively affect the test, but there's no other way.

I have also added the error log from the engine electronics here.

[Translating...]

Gaspedalstellung ist so gut wie nie Vollgas (100%), leider recht sinnlos das Log... in einem Bildchen mit Titel "wellenförmige Beschleunigung" war vor allem das Fahrer-Wunschmoment wellenförmig.

Hi,

I have now recorded another run with MWB 080 and 010, including longer full-throttle phases.

I hope that this file will be useful.

When accelerating to full speed, there was a slight decrease in performance, which should be reflected in the numbers. I'm sorry, I can't see where.

However, it seems that the torque limit is always below the smoke limit. As far as I understand it so far.

For an interpretation of the logs, if they are useful at this point, I would be grateful.

Greetings
Ronald

[Translating...]

Hallo,

man sieht tatsächlich Einbrüche beider Luftmasse obwohl das Gaspedal bei 100% bleibt. Ich vermute, die Einbrüche sind sehr kurz aber stark und daher schlecht an den Messwerten (niedrige Abtastrate) zu sehen.

Ich vermute ein Problem mit der Verkabelung zum LMM, den LMM selbst oder ein schlechtes (vermurkstes) Chiptuning in der ECU.

Auch der Ladedrucksensor und seine Verkabelung ist verdächtig, denn der Ladedruck ändert ebenso wie die Einbrüche sehr schnell, IMHO etwas zu schnell, da die Turbine und deren Verstellung eine gewisse Trägheit hat.

Auch mal die Betriebsspannung der ECU im Auge behalten, nicht dass es Probleme mit deren Stromversorgung gibt.

Motorsteuergerätesoftware ist original?

Viele Grüsse, Rainer

Hi Rainer,

Thank you for your response.

Although I had planned to have a new engine installed 50,000 km ago, it was only done so that the car would start running again.
The workshop, as well as myself, have no interest in tuning.
I actually don't have any idea either.
I'm just happy if the car works.

I only installed a new LMM in the fall because it seemed like the simplest and cheapest solution at the time. (49.90 from Hitachi, allegedly identical to the original).
I can, however, reinstall the original version and see if a test drive makes a difference.

Likely, we can rule out the MSG software as a cause, and also suspect the ECU, as I have no interest in pursuing this further.

Is it sufficient to visually inspect the wiring of the LMM for faulty areas and test the connector with a multimeter?

That's all the questions for the first part of your answer.
I'm sorry for all the questions, but I'm more of a driver than a mechanic.

Best regards,
Ronald

[Translating...]

Quote:

000257 - Luftmassenmesser (G70) P0101 - 000 - unplausibles Signal Umgebungsbedingungen: Fehlerstatus: 01100000 Fehlerpriorität: 2 Fehlerhäufigkeit: 1 Verlernzähler: 255 Kilometerstand: 214500 km Zeitangabe: 0 Datum: 2024.04.11 Zeit: 18:35:51

Bei so einem Fehler macht man keine Experimente mit einem LMM der "angeblich" passen soll, sondern verbaut ein Originalteil.

Nein, zur Prüfung eines Kabels mit Steckern was sich im Betrieb bewegt und vibriert reicht es nicht ein Multimeter ran zu halten.

Nochmals, Du hast sehr wahrscheinlich ein Kabel-/Steckerproblem und/oder einen unpassenden LMM und/oder Spannungsversorgungsprobleme mit der ECU wo du nie Rückmeldung liefertest.

Kann ja nicht schwer sein, ein Kabel mit Steckern vollständig auf Funktion zu prüfen, Scheuerstellen und Kabelbrüche auszuschliessen. Wenn Dich das überfordert, ist die Audi Vertragswerkstatt für Dich die bessere Anlaufstelle.

Viele Grüsse, Rainer

Hi,

Now, thank you for the response.

I have now installed a Bosch LMM, which corresponds to or contains the Bosch G70 article from the previous supplier.

The wave-like acceleration is no longer perceptible at the moment.

Since I mainly drive short distances in my car, I cleaned the AGR valve and the throttle body about 8 weeks ago. Four weeks ago, I replaced the intake manifold because, after removing the AGR valve, I also found a lot of oil sludge there, and I wanted to know how far the dirt problem extends.

Fortunately, there wasn't much to verschandeln on the engine side. However, the AGR valve looked quite bad. If needed, I can provide an additional image.

Last week, I checked the intercooler hose, which is attached to the turbo, and noticed that it was oily on the outside, but thankfully almost dry on the inside. (I can also provide a picture here)
Since I just installed the new LMM, I was wondering what your thoughts are on the oil film on the old sensor. See image.
Does the oil come from a faulty crankshaft case, or in which direction should I continue to look?

Thank you for your support.

Best regards,
Ronald