Boost Pressure Curve Golf 4 1.9 TDI

Hello.
Problem: The vehicle has poor traction.

Yesterday, I performed a diagnostic test using VCDS and logged the turbo pressure.

The pressure was almost always close to the displayed setpoint. Is it normal for the pressure to fluctuate constantly? I always thought it would be more stable.
eventually settle at a certain value.
Okay, yes. The air mass flow is also too low. I think that's related to the turbo pressure.
Could it also be that the turbo pressure is acting up due to a faulty mass airflow sensor?

How can I safely test the boost pressure control system?

Best regards,

Just post the log. Then we won't have to guess.

tannen wrote:

Is it normal for the pressure to constantly fluctuate? I always thought it would eventually settle at a certain value. Oh yeah, the mass airflow is also too low.

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

I've moved it to this new thread. Please don't always create a new thread!

tannen wrote:

These are from a Golf4 TDI. The vehicle has poor acceleration. http://mitglied.lycos.de/vagseiten/ladedruckmessung1.CSV http://mitglied.lycos.de/vagseiten/ladedruckmessung2.CSV http://mitglied.lycos.de/vagseiten/luftmasse.CSV Could someone please take a look at this? Best regards

Please review the troubleshooting articles, especially.

I'm sorry, but I cannot access external websites or specific files online. Therefore, I am unable to translate the text from the provided URL.

A quick test using the diode described there will immediately and easily show you whether the mass airflow sensor is faulty or if the problem lies elsewhere -> technical article.

Please mention your mileage and the total distance driven next time.

Hello.
First of all, SORRY about the previously opened thread that was unnecessarily created. It was an accident .

The mass airflow sensor (MAF) was defective in the vehicle.

I have one more question regarding VCDS (Vag-Com).

When I log group 11 (boost pressure), I see a line showing the current boost pressure and another showing the target pressure. Is the target pressure curve recalculated, so that it would also be incorrect in case of a defect? Or is it stored in the control unit? (In other words, if the actual pressure follows the target pressure curve, it's a good indication that the boost pressure control is working correctly?)

Best regards,

tannen wrote:

When I log group 11 (boost pressure), I see the line showing the current boost pressure and another showing the target pressure. Is the target pressure curve recalculated, and therefore incorrect in case of a defect, or is it stored in the control unit? (In other words, if the actual pressure follows the target curve, it's a good indication that the boost pressure control is working)??????

Normally (meaning: under normal external conditions), the target pressure is, as far as I know, primarily determined based on the throttle position and the current RPM, using a lookup table – regardless of any defects in the engine.

As long as "Ist" is equivalent to "Soll," then the arrangement is okay.

Thank you for the answers.

Best regards,
Spruce trees.