Bosch Mass Air Flow Sensor: Still Bad?

Hi fellow DIY enthusiasts,

I need to share something with you all, for your information, about the frustrating topic of Bosch mass airflow sensors.

Okay.
I recently had to replace a component that was installed around January 2004 due to increased consumption.
(Exchange ) LMM (Lambda Sensor). Original Bosch in our Passat Variant, replaced under warranty (Kulanz). He thought it ran better and had less fuel consumption before.

The unpleasant surprise came the very next day after the installation:

'When I installed the brand new Bosch mass airflow sensor with a production date of 06/2004, I had absolutely no power, and the fuel consumption was higher! No matter how much I pressed the accelerator, whether fully or only half as much, the car ran so poorly that I had to reinstall my 'emergency' mass airflow sensor, which has been modified.'
I was a real obstruction to traffic.

After my repeated auditions at the , the discussions naturally really started. However, I, THANKFULLY, didn't let myself be discouraged.

Based on my receipt, I was able to get my old item back, after a lot of arguing and questions about whether I even knew what I was talking about, etc.



Unfortunately, for me, it still seems that the problem could not be solved in any way. The issue with the faulty mass airflow sensors is only being downplayed by focusing on the price. I declined to have a measurement done (I was already running very late in the morning, and I didn't want to see what was being done).


There was once some information, or perhaps a rumor, that Pierburg was supposed to offer a mass airflow sensor (MAF sensor) with the correct calibration starting in early 2004. Does anyone know more details about this?
Hopefully, it won't be a waste of money. The DC_LMM looks good visually, but the performance is lacking at the lower end!

Before the questions start:

The car runs well with the 'old' part, but I still believe that it had less fuel consumption and more torque when it was freshly replaced.

Furthermore, I find it completely unacceptable that this vulnerability is still being blamed on the customer. It's a ridiculous mentality! VW should be held liable for this.

The worst part is that the values of these broken devices are still within the tolerance range, who actually defined that tolerance?

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

'So long'

This phrase is a common way to say goodbye in English. It is similar to the German phrase 'Auf Wiedersehen'.

Here are some other ways to say goodbye in English:

* Goodbye
* Bye
* See you later
* See you soon
* Have a good day
* Have a good evening
* Have a good night

I hope this helps!
Thorsten.

Hmm... that's a strange correlation: less power, but more fuel consumption. It's not typical for a faulty mass airflow sensor (MAF), because a faulty MAF usually reduces the fuel injection amount.
'... A real traffic obstruction would actually mean an emergency stop.'
Regarding Pierburg: they probably won't be interested in supplying mass airflow sensors for VW/Audi anymore, especially since there are now cheaper alternatives available from Bosch.

Hi.

I've also been working with my Large Language Model for quite some time.

Try creating a graphic like this:



As far as I'm aware, the "as-is" curve should be much flatter in the higher RPM range, and therefore shouldn't drop off as significantly.

One should also be able to recognize the condition of the mass airflow sensor based on that.

m;

Please provide logs with the air mass values.

As someone who has used a lot of these things and experienced a lot of failures, I can share some insights. In my experience, they would typically fail completely within a very short time after being replaced, and the air mass readings would drop to 0 mg/stroke.

Take a look at this; maybe it will help you a little bit too.

where??

0 mg should result in 0 mg of diesel.

The replacement value is only set when there is absolutely no measurement data available, right?

m;

Alois wrote:

Hmm... that's a rather strange correlation: less power, but more fuel consumption. It's not really typical for a faulty MAF sensor, as a faulty one usually reduces the fuel injection amount.

Okay.
However, the boost pressure is set so high that the amount of fuel actually requested by the pedal could still be burned – which is unnecessarily high, considering the now-reduced fuel injection amount due to the mass airflow sensor (MAF) modification.

And (an unnecessarily high) boost pressure cannot be generated out of thin air; it requires energy.
Where does it ultimately come from? From gasoline, where else?

Considering that a TDI turbocharger can extract up to 20 horsepower (IIRC) from the exhaust gases in its maximum pressure range, it might become clearer that the fuel consumption can increase, at least somewhat, with unnecessarily high boost pressure... even though the overall efficiency of the engine increases due to the turbocharging.

where ??

0 mg should result in 0 mg of diesel.

The replacement value is only set when there is absolutely no measurement data available, right?

m;

No!

There's a certain threshold value that, while the engine is running and under specific conditions, must not be exceeded or fallen below. If this threshold is reached, the centrifuge goes into emergency mode, and a value of something like 500 and 'crushed' mg/hub is displayed. At least, that's what happened/is happening with mine.

The error memory always indicated a short circuit to ground, even though there were still voltages of just under 1 volt present when the engine was idling.

IMM values in the corresponding measurement group in VCDS.

dieselmartin wrote:

Try creating a graphic like that:

Hi Martin,

Why not perform a measurement using the "extended" DZR driving cycle up to approximately 4500 rpm?
This results in two clear lines for the target and actual values, instead of that (in my opinion, difficult-to-understand) "collection of curves."

Furthermore, it is not the difference between the target and actual air mass that is crucial for power loss, but rather (in most engines) the difference between the torque and soot limits.

If you log both types of transactions (MWB), you can see that the two invoices don't necessarily have to be identical.

@ Ulf

It's important to understand that a "small amount of air mass" alone doesn't necessarily cause a limitation. Conversely, a "large amount of air mass" won't result in a limitation. Also, I find 700 mg to be a small amount even for a single dose. By the way, the Russian limit is already being reached in my case – I've already measured it – but I didn't have this log available at the time, hence the unusual curve.

@ Joergs
"Recently, I encountered a problem with an Ibiza ASV. It seems there was a loose connection at the MAF sensor connector. This resulted in erratic fuel injection readings, especially during hard acceleration (the twisting of the intake manifold was likely necessary to cause the connection to wiggle, hence it only happened during acceleration). As a consequence, the EDC (Engine Control Unit) reduced the fuel injection amount, and the engine started misfiring like a young bull."
With the LMM (Latent Membrane Protein) removed, the replacement value was 525 mg, and the acceleration was acceptable.

After reattaching the LMM connector, everything was gone!

I will patch my LMM with 22kΩ next time - because no one wants to give me an old Pierburg to tinker with .

m;

@dieselmartin

It takes a certain amount of time for the system to recognize this sudden 0mg change and react to it, which delays the setting of the warning value. It's likely that the interval was too short in your case, so the system hasn't yet recognized it as critical.

@ulf

Do you mean something like this?

dieselmartin wrote:

@ ulf: Do you mean something like this here:

Yes, basically the same...

If the image were a little smaller, so that the thread would also fit on my 19" monitor without having to scroll left and right, it would be perfect .

If you had a resolution that was suitable for a 19" screen, it would fit .

I can easily fit it on my 18-inch wheels.

Next time

m;