LMM Statistics: Analysis and Interpretation

Hello fellow DIY enthusiasts!
What do you think about a statistic on the frequency of errors in specific LMMs?
This weekend, I cleaned my mass airflow sensor (MAF) with brake cleaner again to try and fix the issue where the MAF value was too high above 3000 RPM. I will be using VAG-COM to check the readings later.
Anyway, I found the following model in my A3:

VAG No. 074 906 461
Manufacturer: Pierburg (Part No. 7.18221.01, PBT-GF/M40)

It is evident that both Pierburg and Bosch LMMs (Mass Air Flow Sensors) are used in VAG (Volkswagen Group) vehicles.
Are there already significant differences in quality?
Is there any interchangeability between different brands? For example, could I install a replacement mass airflow sensor (MAF sensor) from Bosch in my car? If so, what is the part number?

Are there perhaps some particularly sensitive components, and on the other hand, also very robust parts?
What do you think about shedding some light on the topic of Large Language Models?

I am currently also looking for a cheap replacement (in case the cleaning procedure didn't work ), and of course, I would like to purchase a component with a longer lifespan.

Thank you for your opinions, suggestions, and any other information.

Regards,
Alex.

I would like to know who started this nonsense about using brake cleaner.
If the mass airflow sensor (MAF) is broken, it's completely broken and unusable.

In the good old days of the 1Z engines, the mass airflow sensor (MAF) was a 'glow wire' type from Pierburg, and cleaning it with brake cleaner helped.
The newer models, for example, in the PD series, are using some kind of encapsulated components, so it's probably not possible to modify them anymore.

If (greasy) dirt is on the sensor surface, incorrect readings will be taken. That's the fact. Each person should be able to judge whether this is the case -> Lucki lucki. Then, you can spray brake cleaner on it.

Best regards, Rainer.

"Yes, if there was old dirt on it, I would definitely verschandeln it. But how did the oil get there, and how did the dirt get there? I mean, what's the point of having an air filter? I have 141,000 km on my car and there's no dirt and no oil. Maybe I should buy a sports air filter so I have something to clean."

Quote:

Maybe I should buy a sports air filter so I have something to clean.

Well spotted .

Good evening.
As far as I know, the crankcase ventilation system is leaking. And the oily smoke then gets sucked into the mass airflow sensor (MAF).
or am I wrong?

Deleted upon request.

@diesel.gustav

So, you mean that the injectors, which are currently used in PD engines, can simply be cleaned? How is that done? Do you just submerge them in water with additives, or can you use a harsh method with brake cleaner and that's it? These injectors are very heavily encapsulated, unlike, for example, the glow plug injectors from the 1Z engine!

Deleted upon request.

Hello donalexo,

I have a Bosch hot-film mass airflow sensor (MAF) in my AFN engine. Starting around 50,000 km, I've experienced a gradual loss of power. I've cleaned it several times with alcohol, but it only provides temporary relief. Visually, there was nothing noticeable on the sensor plate.

Dann neues Teil bei ebay ersteigert - 89 Euro. Complete success.

'Question to the community: Does anyone have information about the internal electronics of the sensor and/or its characteristics? I can easily imagine wanting to experiment with the old part and a vacuum cleaner one Sunday.'

Best regards,

Helmut.

Hello everyone!
During the Easter holidays, I drove approximately 1400 km on the highway. Unfortunately, I noticed that my A3, despite having cleaned the mass airflow sensor (MAF sensor) beforehand, seemed to be lacking its full performance. What's even worse, however, is that the fuel consumption was above average, despite the very likely low MAF sensor reading.
My fuel consumption on the highway was unusually high: 6.5 liters per 100 kilometers, with moderate driving (mostly between 140 and 160 km/h, very rarely exceeding 180 km/h). Previously, with similar driving, my consumption was just under 6 liters per 100 kilometers!
I will probably perform a final measurement using VAG-COM this weekend to decide whether or not to remove the mass airflow sensor.
Here's the translation:

"I have a question for the experts here: My EGR valve uses the mass airflow sensor with the VAG part number 074 906 461. However, this seems to be a relatively rare part on the open market (eBay). The 06A 906 461 is much more common there. Can I use that one instead, or are there any differences in the mounting dimensions to the air filter housing, the connector, or the air hose?"
As far as I know, the newer AGR engines were equipped with this mass airflow sensor. How do they differ? At least the performance curve should be the same, right?
Who can help me?

Sure, here's the translation:

"Thank you in advance."

Regards,
Alex.

Hello TDI community!
As promised, I'm providing my measured values regarding the mass airflow meter (MAF) issue here. The measurement results were recorded just about an hour ago using VAG-COM. The measurement was taken in 3rd gear, with full throttle, going steeply uphill, so the acceleration wasn't excessively high (please consider this when evaluating the boost pressure build-up).

Please form your own opinion first. From left to right, the columns represent: engine speed, mass airflow sensor value, air pressure, target boost pressure, actual boost pressure, and wastegate valve duty cycle.

n LMM p_Air p_Target p_Actual WG
1/min mg/R mbar mbar mbar %

1365 475 979 1306 1000 34.7
1470 575 979 1785 1122 34.7
1680 715 979 1887 1285 35.1,
1932 855 979 1918 1581 35.5
2184 905 979 1897 1826 35.1
2436 915 979 1887 1979 41.4
2688 835 979 1877 2030 59
2940 815 979 1867 1867 62.2
3150 790 979 1867 1897 64.1
3381 765 979 1867 1877 65.7
3612 745 979 1856 1867 67.3
3801 730 979 1846 1856 68.5
4011 695 979 1826 1846 69.7
4179 660 979 1805 1785 68.1
4347 635 979 1775 1744 65.3

I think you will strongly advise me to get a new LMM, right? The drop in the LMM value at higher RPMs is quite significant, I think!
Assuming that the amount of fuel injected is reduced proportionally to the measured air mass, and that the power output is proportional to the amount of fuel injected, then my engine currently produces only about 74 horsepower at its rated speed (4000 RPM), whereas it used to produce 90 horsepower.
That would then be a good reason for me to start tuning the LMM !

I'm not particularly happy with the turbo boost build-up in my TDI. In my opinion, the maximum boost is reached much too late, at around 2500 RPM. I would have expected the initial boost to kick in at 1900-2000 RPM. Overall, the entire boost build-up in the lower RPM range seems very sluggish. Although it was accelerating in 3rd gear, it was on an incline of about 8%, which should have given the engine enough time to regulate the turbo boost.
Could my power loss potentially be caused by something other than the mass airflow sensor? What about a wastegate that isn't closing completely, which only generates enough back pressure at higher exhaust flow rates to get the turbocharger working? Above 2600 RPM, the turbo boost control system seems to be working perfectly.

I am eagerly awaiting expert advice!

Regards,
Alex.