MWB 11: Questions and Answers

Hello everyone!

I've been using VCDS for about 3 weeks now, and I have a question about control module byte 11.
"Yes, it should display both the target (Soll) and actual (Ist) boost pressure, but I don't understand it because it shows the values in mbar. If I convert that to bar, my AFN engine, which already has 0.9 bar of boost pressure in the stock configuration at idle, would have approximately..."
The actual boost pressure is 1.98 bar, but I don't think that's quite right, and I might be making a mistake in the conversion.

Best regards, Tom.

Hello,

You need to subtract the ambient air pressure (see MwB 10). Depending on the weather and altitude, this is typically between 950 and 1000 millibars. At higher altitudes (e.g., mountain passes), it is significantly lower.

Best regards, Rainer.

The absolute pressure is displayed. You need to subtract the ambient pressure (usually around one bar) from this value to obtain the pressure difference, which is known as the boost pressure.

EDIT: too slow

In my opinion, those numbers were still too high for the AFN. Instead of 1.98, it should have been 0.98, but 0.6 is the normal maximum pressure for the AFN with overshoot.

Quote:

0.6 is the normal maximum pressure in the AFN system with overpressure

.
No. Normally, the absolute pressure should be a maximum of 1950 millibars.

Do you happen to have a repair manual for the AFN engine?

Thank you in advance.

Best regards,
Thomas.

What do you want to know?

Well, basically everything.

Best regards,
Thomas.

Okay, then I'll reveal something more: 1980 mbar (1.98 bar) will be displayed on the AFN if the tuner, let's say, is aimlessly searching in the noise.
There is no AFN with a 1980 mbar series.
And that's with a common engine, one that's been around for 15 years.

This should give you something to think about and proves that buying the diagnostic tool was a good idea.

And that means, specifically...

ThomasJ wrote:

And that means, more precisely,

The person responsible for the 1980 mbar reading seems to have no idea what they're doing, and there might be other hidden issues.

It might not be entirely accurate because the previous owner of the vehicle was older and didn't modify the car.

Best regards, Tom.

You wanted to know everything, and in my opinion, a note should be added to everything stating that there is no AFN (Air Fuel Needle) with a target pressure of 1980 mbar.

I'm currently seeing...

Quote:

The actual boost pressure is 1.98 bar, but in my opinion, that might not be entirely accurate.

What the actual value does is a different matter; it can be higher or lower.

How can I insert a log file here so you can check it yourself to see if it's okay or not?

Best regards, Tom.

Okay, I'm ready. Please provide the German text you want me to translate.

Hello everyone.

How can I identify which engine control unit (ECU) is installed?

Best regards, Tom.