Passat Variant AKN: Specs, Max Speed & Measurements

Hello,

I recently became the owner of a used Passat Variant AKN. I am generally very satisfied, but I am somewhat disappointed with the top speed.
The vehicle registration document states a top speed of 214 km/h. According to the speedometer, this is achieved with great effort and tailwind, which likely corresponds to a real-world speed of around 205 km/h. (Tires: 205/55 R16, no additional modifications except for roof rails).
The measured values for air mass, turbo pressure, and fuel injection volume are mostly within the normal range.



However, the actual air mass is slightly behind the target value, but the fuel injection quantity is limited by the torque limiter and not by the smoke reduction system.
Okay, here are the specific questions about that:

'The EGR valve's duty cycle is constantly 95.5%. Does this mean it's always fully closed or always fully open, and is that normal?'
2. Erscheinen mir die Werte für Einspritzmenge Fahrerwunsch im unteren Drehzahlbereich recht hoch. Is that normal?
'Does anyone else among you have the same engine in their Passat, and what is the top speed?'

Thank you in advance.
Greetings.
Jean.

Hi,

I certainly won't analyze your pile of numbers.

If you don't want to/can't upload a picture, then at least separate the individual values with some hyphens or underscores; it will make things much clearer.

Okay, you're right, I hope it's a little better now.

Regards,
Jean.

Kruegerjean wrote:

Okay, you're right, I hope it's a little better now.

I actually meant separators between all numbers and between the labels, so that the type of data is above each respective column.

Removing redundant data like speed and timestamps down to a single column can also improve clarity.
And the more readers will take a closer look at the data!

or just use Excel; it takes less than two minutes, and you'll have it perfectly organized .

Hello,

Install a new mass airflow sensor, and it will have its specified performance again...
Are there any exchange programs available at VAG now? Roughly speaking, it costs around €80.

Best regards, Christian.

Put in a new mass airflow sensor, and then it will have its specified performance again.

I've also considered that, and it will probably need to be replaced soon due to the slightly lower actual air mass readings. If the Mass Air Flow sensor (MAF) is responsible for the reduced power, shouldn't the smoke emission test show the lowest value?

Here are the logs again, in an Excel table format. Hopefully, uploading works this time.

Replacing the mass airflow sensor is unnecessary.
The values look excellent. At 3000 RPM, 871 mg is like new.

Best regards, Manuel.

Kruegerjean wrote:

If the mass airflow sensor (MAF) is responsible for the reduced power, shouldn't the smoke test show the lowest value?

Of course that's correct!

Can anyone tell me about the top speed of a car with the same engine or AFB (presumably referring to an engine code)? Perhaps the manufacturer's stated top speed is overly optimistic.

What about the EGR valve? The values are constantly at 95.5. Does that mean the EGR is always open or always closed?

Thank you for the previous answers.

Regards,
Jean.

Replacing the mass airflow sensor is pointless.
The values look excellent. At 3000 RPM, 871 mg is like new.

Best regards, Manuel.

Yes, and what? How are the other values in the different speed ranges?
The thing is broken and beyond repair.


@kruegerjean

Your AGR (Abgastrückführung) values are at 95.5 because you're driving at full throttle during the test. When driving at full throttle, or more accurately, full load, the AGR system is always closed. If you drive at partial throttle, the value will be different.
If your air pressure is correct again, your car will also reach speeds of 220-230 km/h according to the speedometer. I have experienced these speeds in various models, such as the A4, A6, and so on.

Best regards, Christian.

Polo2004 wrote:

Yes, and what? How are the other values in the different speed ranges? The thing is broken and beyond repair.

Check the logs before jumping to conclusions!

Starting around 1500 (presumably a value on a gauge or display), the torque limit is always at its lowest point! Therefore, the mass airflow sensor (MAF) is working correctly!

Yes, and what? How are the other values in the different speed ranges?
The thing is broken and beyond repair.

Check the logs before jumping to conclusions!

From approximately 1500

Have you ever seen a broken mass airflow sensor? I think I can tell what's broken and what's completely gone after installing about 30 of them.

But we will see...

Polo2004 wrote:

Have you ever seen a broken mass airflow sensor? I think I can tell what's broken and what's completely gone after installing about 30 mass airflow sensors.

Then, please define the parameters you use to identify a faulty mass airflow sensor (MAF).

The fact is that in KruegerJean's log, the LMM (likely referring to a specific component or setting) does not appear to be limiting! While it may no longer be the best performing, it still consistently reports a value of 850mg and would likely deliver more if allowed.

Because, as "Wolfi-B" already mentioned, in this specific engine control unit (ECU) software, the amount of fuel injected is limited by the torque map at higher RPMs, not by the air mass flow rate (MAF) sensor, which would otherwise be a limiting factor.

I recommend that KruegerJean logs the data again in the relevant range (specifically at Vmax), and if the Russian limit doesn't come into play there, then the mass airflow sensor is definitely not at fault.

Furthermore, Polo2004 should provide some justification for his statements instead of simply making empty remarks. This is a professional forum, not just a casual gathering.

Regards,
Sure.

Here is the translation of the text from German to English:

"Guste" means "gust" in English. It can also be used as a verb, meaning "to gust."

While he may not be the best anymore, he's also someone who consistently reports a value of 850mg, even though he wouldn't actually deliver that much in terms of injection volume.



That's how I interpret the data as well. By the way, this is an LMM from Hitachi. I read somewhere that these are supposed to be more durable.
However, if no other cause can be found, I will replace it, as it is already showing signs of weakness, and a replacement would likely be necessary in the near future.

I've read in this forum before that during a timing belt replacement, the fuel injection pump can be misaligned, which shifts the adjustment range for the injection timing. Can I detect this error by reading block 4 (injection start time is/should be)?
Or is this mechanical fault continuing in a way that the electronics don't detect it?
(doesn't know where the signal is being received from).

I've noticed in the log that the fuel injection amount based on driver preference is exceeding the target values by up to 10 mg per injection, especially in the lower RPM range (values 45-49). While this might not necessarily indicate a problem, it seems somewhat unusual to me.

Right now, the car is at the workshop for painting. When it's back, I'll log the maximum speed again.

Regards,
Jean.

Hello, I have an AFB engine with a new mass airflow sensor (MAF), and it's producing maximum values of 760 mg/stroke, but still delivering 155 horsepower. I don't understand how that's possible, but that's what's happening...
I've never tested the maximum speed because there are no highways in Luxembourg.

"My problem is still the fluctuating boost pressure, which really ruins the throttle response. I accelerate hard, it seems good initially, then it stays constant, and from 3000 RPM it starts fluctuating again... it's annoying... see the log file. The boost pressure goes up to 2200, then down to 1800, and then back up again."