BMP air mass value too high?

Hello everyone.
I'm experiencing a performance-related jerking issue in my Passat that starts around 2000 rpm. The problem gets worse when the air conditioning is turned on.
The air mass is currently between 1200 mg/h and a target value of 850 mg/h.
The mass airflow meter has already been replaced, and the intercooler piping is leak-free.

Is this normal? Is the boost pressure too high, or is the boost pressure sensor faulty?

Sure, here is the translation of the text from German to English:

"LG" translates to "Best regards" or "Sincerely" in English. It is a common abbreviation used at the end of emails and letters.

Hello,

Is an original mass airflow sensor installed, or one from some cheap foreign country?
Try installing a different LMM (original part), and the measurement module is available as a separate component.

Depending on the boost pressure, 1200mg/H is considered "normal," and no adjustment takes place at this operating point.
Is the data set in the engine control unit (ECU) original?

Best regards, Rainer.

Hi Rainer,

Yes, it's an original LMM (mass airflow sensor) that was installed. The "old" one provides the same readings.

To the best of my knowledge, the data set in the control unit is original.

The measured values from the ambient pressure sensor and the turbocharger pressure sensor.
match/agree within tolerance when the engine is disabled.

You're saying that, depending on the boost pressure, 1200mg/H is a normal value...

How am I supposed to understand this?

If there hasn't been any tampering with the charger or the software of the MSTG... is the charging pressure too high, or within the normal range?

Best regards,

Jan.

Hello,

By the way, the log looks normal, and the LMM also seems to be okay.

Best regards, Rainer.

Hi Rainer,

Thank you for your quick response, and for...
The assessment of the log.

Best regards,
Jan.

Hi there,
Atmospheric pressure: 918 millibars. Isn't Olten located at a much higher altitude than that?
hg
Herbert.

Herbert wrote:

Atmospheric pressure is 918 mbar. But Olten isn't that high up, is it?

Google Maps shows me contour lines there in the approximate range of 600-800 meters.
In the lower layers of a planet's atmosphere, the pressure decreases at a rate of 1 millibar per 8 meters of altitude.
918 mbar therefore correspond to a local altitude of 760 meters at standard pressure (1013 mbar). That fits perfectly .

@linklon

You can try logging only measurement block 8 (smoke limitation) under full load when you experience the jerking (enable "Turbo mode" in the dialog).

If there is jerking and no discernible drops, then the mass airflow sensor (MAF) and/or boost pressure sensor are likely not to blame.

You can also repeat the experiment using exhaust gas temperatures; excessively high exhaust gas temperatures will also lead to a reduction in fuel injection volume.

The most common next suspect when experiencing engine misfires would be the wiring harness connected to the cylinder head.

Best regards, Rainer.

Thank you for your answers.

"@Ulf and Herbert: The log data you posted was generated at an altitude of approximately 740-770 meters above sea level. In my opinion, the ambient pressure is fine. I'm at home at about 550 meters."
I have a pressure of 948 millibars.

@ Rainer: Thanks for the tip, I'll take a look at the logs when I have a chance.
and post...

Best regards.

Jan.

Hi,

Quote:

In the lower layers of the atmosphere, the pressure decreases by 1 millibar for every 8 meters of altitude. 918 mbar therefore correspond to a local altitude of 760 meters at standard pressure (1013 mbar).

I also know that.
Olten, located in the canton of Solothurn, is listed on Wikipedia as being approximately 396 meters above sea level, while the surrounding mountains are around 700 meters high.
That's why the question.
Perhaps I went to the wrong Olten.
hg
Herbert.

Hello.
Finally managed to create the logs...


I now suspect there is an electrical or electronic problem.
Fehler ist nun zeitweise auch im Schubbetrieb spürbar. Not that strong.
Like when accelerating, but noticeable as a slight knocking/tapping sound.
If I turn off the climate control (which operates in "Eco" mode without using the compressor),
The problem can either be completely eliminated or significantly reduced.
The knocking is usually more noticeable in humid or wet weather than when it's dry.
is dry.

When the engine is idling, I'm measuring a voltage of 0.032V between the battery's positive terminal and its ground connection.
Between the alternator and the positive terminal of the battery: 0.060V.
Using a multimeter, I'm measuring a voltage of 14.2V from the alternator positive terminal to the engine block.
The voltage measured above the battery is 14.11V.

The battery's open circuit voltage is 12.7V.

I've noticed that in the MWB 16 (likely a piece of equipment), the supply voltage increases during operation, reaching up to 14.74V when the generator load is between 15% and 20%.

Are the 0.06V between the alternator and the positive terminal too much? Does anyone have any ideas?
how this behavior can be explained in terms of thrust, and what the connection is.
What can you do with climate control?

Best regards, Jan.

Both seem fine and, if the logging process was experiencing lag, they probably aren't the cause of it.

Quote:

Ich hab ein leistungsabhängiges Ruckelproblem ab 2000rpm an meinem Passat. Bei eingeschaltener Klima verschärft sich das Problem.

Quote:

Fehler ist nun zeitweise auch im Schubbetrieb spürbar. Not that strong. Like when accelerating, but noticeable as a slight knocking/tapping sound. If I turn off the climate control (which operates in "Eco" mode without using the compressor), The problem can either be completely eliminated or significantly reduced. The knocking is usually more noticeable in humid or wet weather than when it's dry. trocken ist.

Is it now shaking or knocking, or both? Please describe it as precisely as possible.

If the problem occurs even in absolute sliding mode (without any assistance), then electrical faults can likely be ruled out.

It's important to first determine if the problem might not be a mechanical one.

What happens if the ignition is switched off while the vehicle is in drive mode?


I find it hard to believe, but if shutting down the climate control system reduces the problem, I would take a closer look at the generator's operation.

How many kilometers are showing on the odometer?

@ Rainer, thank you for the quick assessment.

I suppose I should tell you a bit more about the history of this car...

I'm sorry, but I cannot access external websites or specific files online. Therefore, I am unable to translate the text from the provided URL.

Here's a brief overview of what I've already done:

Have the auxiliary engine completely overhauled.
Get your hair checked/reviewed.
ZMS replaced by LUK.
LMM replacement -> Bosch original part.
Replaced all PDE components with genuine Bosch replacement parts.
PDE wiring harness replaced -> original part.
Diesel filter replacement.
Pre-charge pump checked.
Replacement tandem pump -> original part.
I also have a charger, but it's not related to the current problem.

The car currently has approximately 136,000 kilometers on the odometer.

"@autoservice Yes, the knocking can be felt even with no load, but it's not always present and only occurs above approximately 2000 rpm. It's clearly noticeable under partial and full load, especially when the engine is cold or when it's raining outside. It's a slight knocking sound."
It's noticeable in the feel of the gear lever and the steering wheel.

Wie lässt sich der Freilauf des Generators am schlausten prüfen? RSure, here's the translation:

"Do you want to go somewhere?"
Yesterday, I unplugged the generator and drove like that. It was almost quiet in idle mode, but the problem persisted under load.

Best regards, Jan.

Quote:

Wie lässt sich der Freilauf des Generators am schlausten prüfen? Riemen weg?

Yes, it's best to take the belt off.

It seems your vehicle has had quite an eventful life so far...

Unfortunately, I only understand about 90% of what he's saying, but it seems like there's a vibration or knocking sound, which could be related to the suspension, such as the drive shafts.