A3 2,0 TDI BKD seltsames Leistungsverhalten Gang 1-3 | Posts 16+

Okay, so when the engine is off, the VTG (Variable Turbine Geometry) is not activated.
When the engine is running, does the vacuum pull the VTG rod towards the diaphragm?
While idling, disconnect and kink the vacuum hose leading to the VTG valve – this will put the VTG into a state as if the engine is off.
It should be fine as long as you just bend the hose; of course, nothing will change with the trailer coupling if you're not allowed to disconnect it.
I expressed myself somewhat ambiguously. Sorry about that.

Yes, then it fits like that.

Attached is the log file, unfortunately a bit late, showing data from the 4th gear with the turbo starting to engage.

Oh yes, I completely forgot to mention: in the meantime, the EGR valve and throttle body have been completely cleaned and reinstalled.
Everything without any improvements whatsoever.

Too bad, but the log looks good.

I would continue investigating in this direction: Either the variable geometry turbine (VTG) is intermittently malfunctioning, or there is intermittent loss of vacuum at the control valve.

I'm thinking of replacing the N75 sensor just in case...?
What is the price of this extremely strange-looking N75 part from the tractor...? Does anyone know?

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I think I'll just replace the N75 part as a precaution...? What is the price of this extremely strange-looking N75 part from the tractor... does anyone know?

Why? Perhaps one of the other control elements, or pressure regulators/actuators, is intermittently leaking, or the connections are reversed, or something else... I've seen it all before .

Therefore, you should check the vacuum pressure at the moment the error occurs, or systematically replace everything one by one .

Okay, I will do that!
What is the purpose of the pressure regulator/controller?
The turbocharger boost pressure is regulated by the VTG (Variable Turbine Geometry) on the tractor.

The connections to the N75 are all correct; they have already been checked twice and confirmed to be accurate.
I would love to exchange everything with the rich person... but financially, it's simply not feasible for the owner.

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What is the purpose of the pressure regulator/controller?

Okay, "pressure sensor" would be the correct term. So, for example, the N75 is a pressure sensor.
The EGR valve is also powered by a pressure sensor.

Look: http://download.ms-motor-service.com/ximages/pg_si_0065_de_web.pdf

A single leak in the vacuum line... and the N75 valve no longer receives the correct vacuum pressure.
Therefore, we check .

P.S.: Right now, you're just as knowledgeable as when you started – you still don't know whether the target landing point (TL) is being correctly aimed for or not.

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A single leak in the vacuum line... and the N75 no longer receives the necessary vacuum pressure. Therefore, please check icon_exclaim.gif

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For example, connect a vacuum gauge somewhere in the system and then run the VTG actuator diagnosis.

Okay, as I said, we'll test it today to see if there are any bugs or issues.
I understand exactly what is being targeted.
We also checked that the vacuum lines were correctly assembled according to the diagram.
http://simplement.skoda.free.fr/technique/egr/egr-05.jpg

We will connect a vacuum gauge to the VTG (Variable Turbine Geometry) sensor and observe how the vacuum changes when the turbocharger is engaged and when it is not.
If both situations provide the same vacuum conditions, then the problem must be with the transmission line (TL).

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For example, you could integrate a vacuum gauge somewhere and then run the VTG actuator diagnosis.

Check for faults during driving (if no boost pressure is building up). If I understood correctly, the VTG system probably functions when the vehicle is stationary.

Absolutely correct! Everything is top-notch when it's stationary/standing still!
Therefore, both test scenarios will be tested during the drive.

Does the VTG have enough traction to accelerate quickly when stationary?

Or is the lever moving towards its limit?

You would need something like that on the VTG container during transit.

Attach the pressure gauge to the outside of the windshield using adhesive and connect it to the VTG with a T-connector.

Yes, the additional volume of approximately 80 cm of supply line will further dampen the VTG (voltage transient generator), but not as much as the error you described.



This is the system vacuum pressure (measured at the supply to the swirl flap valve of the BMR) while the VTG is in actuator diagnosis mode.


Okay, please provide the German text you would like me to translate into English. I will only provide the translation.

After the engine starts, the variable geometry turbocharger (VTG) immediately moves to its operating position. We will use a pressure gauge exactly like that one.
However, we need to test the behavior while it's in motion; everything seems fine when it's stationary.
The throttle lever only works under load and at low speeds (or, it only functions properly when you briefly release the pedal and then press down on it fully to move forward).

Here's another piece of information about the VTG (Variable Turbine Geometry): If you unscrew the housing on the turbocharger (it's only held in place with two M6 screws), then the adjustment lever and its housing should simply fall downwards.

The adjustment mechanism moves more smoothly than butter (in working condition and with the adjustment housing removed). If there is a hard or stiff spot along the adjustment range, or if the adjustment lever only moves with resistance, this is not normal.