DZR Diagnosis: Troubleshooting Performance Loss

I drive an Ibiza, AFN engine, with 97,000 km. The timing belt and diesel filter are new. During a recent dyno test (2000-4000 rpm), my suspicion of a power loss was confirmed. With an average time of 6.3 seconds, I missed the target time by 0.3 seconds. I drove the course back and forth, took all the values from the DZR (diagnostic reading) into account, and used VAG Com to measure the time. Even if I had achieved 6 seconds, it would indicate exactly 110 horsepower, which is 0% variation from the standard.

The mass airflow sensor (LMM) is still okay, with the values in the lower acceptable range. The boost pressure is also okay, but it drops slightly between 2500 and 3000 rpm, only to return to the normal range above 3000 rpm. This manifests as a slight increase in power felt again above 3000 rpm. The injection timing is very close to the ideal line and is therefore okay. Today, I deactivated the EGR system and could not measure any significant changes with the diagnostic tool (DZR). With the EGR system deactivated, it produces slightly less soot, and the turbo sounds louder (observed from the outside). I also tried the diagnostic options for the turbo and EGR mentioned recently in the basic settings mode. (/viewtopic.php?t=3385&highlight=kammerdiesel) The following values could be observed:

AGR ON: 210 mg/H, target is 260 - 280 mg/H.
AGR OFF: 440 mg/H, target: 450 - 470 mg/H.

Turbo ON: 1000 mbar.
Turbo OFF: 969 mbar.

I have already checked all the hoses and seals and found them to be correct. Based on my explanation, do you have any idea where I might be able to find the problem?

Best regards,

Dennis.

dennis79 wrote:

The boost pressure is also OK, but it drops slightly, just like the MAF sensor value, between 2500 and 3000 rpm, only to be back in the normal range above 3000 rpm.

This manifests as a slight increase in power that I feel again above 3000 rpm.
Hi Dennis,

What do you think the DZR meter will show if you briefly reduce the gas flow during the measurement? }

Have you ever checked the boost pressure curve using a lambda sensor?

Is the VTG (Variable Turbine Geometry) easily adjustable, and are all components, including hoses, magnetic valve, etc., in good working order?