Is emergency mode possible with a faulty mass airflow sensor? Question about the article.

What happens in a TDI engine when the turbocharger control system is functioning correctly?
is, but due to faulty air mass readings, which were dramatic.
too deep, and the injected amounts are not even close.
Is it sufficient to bring the actual LD value closer to the target LD value?
It should trigger something like "intake manifold pressure regulation differential" or similar.
are unclear, as the cause of insufficient LD is unknown.
In the article about "Common causes of errors,"...
"only shows:".
"usually no entry in the error memory."

It is likely that this situation rarely occurs in practice, because the weakening...
It is important to detect LMM early on.
Am I right about this?

Greetings, Klaus.

If you only press the accelerator pedal halfway, do you then have an LD control difference?

The LD target is determined based on the actual amount of solar power injected (i.e., the smallest value in MWB .

LMM reading falsely low -> limitation due to low air mass means low fuel injection quantity -> also, no high target boost pressure.

The target boost pressure can be adjusted even with a fixed fuel injection amount. No difference in regulations, so everything is fine; it's basically like easing off the gas.

Malte1408 wrote:

The LD target is determined based on the actual amount of solar power injected (i.e., the smallest value in MWB .

Then, the desired LD (load demand) would depend on whether or not the accelerator is being pressed.
what the previous load conditions were.
And I have to learn everything from scratch.

"Quote from 'TDI: Basic Principles of Technology I':"
During operation, the electric throttle position sensor sends the driver's desired fuel injection amount to the MSG. This initially determines, based on the programmed boost pressure map, what boost pressure is required to combust the desired amount of fuel "cleanly" within the respective emission class, and then begins to adjust the boost pressure to the corresponding value.
"Quote ends"

It sounds like the desired charging rate (Soll-LD) depends only on the driver's preference (and...).
(of course, depending on the speed/revolutions per minute).

Greetings, Klaus.

Quote:

="Clause" "Quote from 'TDI: Basic Principles of Technology I':" During operation, the electric throttle position sensor sends the driver's desired fuel injection amount to the MSG. This initially determines, based on the programmed boost pressure map, what boost pressure is required to combust the desired amount of fuel "cleanly" within the respective emission class, and then begins to adjust the boost pressure to the corresponding value. "Quote ends" It sounds like the desired charging rate (Soll-LD) depends only on the driver's preference (and...). (of course, depending on the speed/revolutions per minute). Greetings Klaus

Edit: Never mind, it was nonsense, I made a mistake. The target LD (load demand) always looks very digital and follows the pedal input. However, I seem to recall seeing a similar issue with a vehicle that had a faulty mass airflow sensor (MAF), where the load demand (LD) also didn't increase. Hmm...

Malte1408 wrote:

... I mean, is the LD target formed from the amount that is ultimately injected should?

But that's exactly what drivers want.
But earlier, you said:

Malte1408 wrote:

The LD target is determined based on the actual amount of solar injection being used (i.e., the smallest value in MWB .

Shortly after accelerating from partial load.
"I believe the driver's wish is definitely the most..."
Amount in MWB 8.

Best regards, Klaus.

EDIT: Overlap. EDIT2: My first quote is misunderstood.
You can no longer access it through Malte's edit.

Can anyone else comment on the issue?

Quote:

Malte1408 wrote the following:: ... I mean, is the LD target value calculated from the total amount that is ultimately to be injected? But that is exactly what the driver wants.

Regardless of my mistake, that is not the driver's desired value; when I say "ultimately," I mean the control size for the pump or flow controller, and that is never directly the driver's desired value.

Quote:

Shortly after full throttle from partial load. "I believe the driver's wish is definitely the most important thing." Number in MWB 8.

When running at full throttle, the largest injector is always used, and for that reason, it is not injected. The smallest amount is always sent to the pump as a control signal, except during idle speed control.

Malte1408 wrote:

Quote: Shortly after full throttle from partial load. "I believe the driver's wish is definitely the most important thing." Number in MWB 8. When running at full throttle, the largest injector is always used, and for that reason, it is not injected. The smallest amount is always sent to the pump as the control signal.

Okay, bitte gib mir den deutschen Text, den du übersetzt haben möchtest.
We already agree on that.
We initially disagreed on the question of...
whether the target LD depends on it.

Greetings, Klaus.

Hi,

Regarding error messages and limp mode: After having my mass airflow sensor ("LMM") "cleaned" at the ADAC facility in Linthe last year, I experienced significant power problems on the way back. Starting at around 90-100 km/h, pressing the accelerator pedal sometimes had no effect at all. Since the fuel consumption remained low, it was clear that the fuel injection volume was being limited due to the LMM problems (a "Russbegrenzung," which is a power limitation). I didn't attempt any further tests after that. It wasn't a complete failure, because after driving for a few kilometers to let it dry, it started working better (although I didn't push it further until I was sure there were no more damages).

Later, the error log showed a temporary short circuit in the mass airflow sensor.

The LMM in question was operating near its limit after the incident, and approximately 4 weeks ago (about 6 months after the incident), it was replaced by a Pierburg unit.

Best regards,

Jan.

edit: partial exam: topic missed - grade

Jan6K wrote:

Hi, Please provide the text you would like me to translate from German to English. Around 90-100 km/h, pressing the accelerator pedal further sometimes seemed to have no effect at all. Please provide the text you would like me to translate from German to English. It wasn't an emergency situation.

It seems the LD-Ist is completely messed up.
and yet, no emergency power?
Amazing, how is that possible?

I guess I'll have to dust off my old language model.
We need to monitor and then log what happens.

Greetings, Klaus.

Hi,

Quote:

and yet, no emergency power? Amazing, how is that possible?

Um... why? As Malte already mentioned in the first response, the current performance request is chosen as the minimum of the three values: "driver request," "exhaust gas limit," and "torque limit," for the current state. If you now press the accelerator fully, the driver request is the highest, the torque is slightly below, and the exhaust gas limit is very low due to the faulty mass airflow sensor (MAF) => that's exactly what's being used. This then results in a very low fuel injection amount and a very low target boost pressure. And then, the actual boost pressure and the target boost pressure will be roughly equal, assuming everything else is working correctly.

The target boost pressure depends on the selected injection quantity (among other factors), NOT on the injection quantity that results from the driver's request. Consequently, there is also no difference between the target and actual boost pressure, and no limp-home mode. A faulty mass airflow sensor has the same effect as a wooden block under the accelerator pedal.

I wouldn't water the LMM... it simulates the whole thing with a potentiometer!

Best regards,

Jan.

Jan6K wrote:

The target boost pressure depends on the selected injection quantity (among other factors), NOT on the injection quantity that results from the driver's preference. Jan

"Quote from 'TDI: Basic Principles of Technology',"
I'm in my 2nd... Post moved above.
have, conveys a different impression...

Greetings, Klaus.

It probably doesn't necessarily apply to other TDIs, but with the 3-cylinder engines (1.4 TDI and 1.2 TDI), it doesn't really matter what values are read by the mass airflow sensor (MAF) or whether it's completely missing, in terms of boost pressure and performance. I've only noticed an influence regarding the EGR rate. However, my engine's tuning is quite basic, meaning that the fuel injection is almost always regulated to the point where it produces a lot of smoke.
I tested it with new, old, and without LMM.
However, I know of several other people without a chip who have experienced the same behavior from their engines when the mass airflow sensor (MAF) is disconnected.

In plain terms, this means that an old or defective mass airflow sensor will not cause a noticeable loss of power in these engines.

Quote:

In plain terms, this means that an old or defective mass airflow sensor (MAF) will not cause a noticeable loss of power in these engines.

Okay. The observed behavior is due to a slightly different philosophy in the design of the datasets for the respective engines, but it is relatively rare.

Best regards, Rainer.

Hi,

Does that mean, conversely, that these types of engines don't have a speed limiter? Or is it then calculated based on the boost pressure (since the MSG already knows the other necessary parameters)?

In the case of the ASV, a severely damaged mass airflow sensor (MAF) definitely caused a significant loss of power -> lap times increased by 12 seconds compared to the usual 6 seconds (of course, without any error codes being logged, to add that to the initial question).

Best regards,

Jan.

Right, as far as I understand the connections, the smoke reduction is likely mainly derived from the boost pressure.