Fuel Injector Problem: AFN 99" VP37 Pump

The problem is as follows:

When the accelerator is fully pressed, the actual injection start timing drops dramatically to 0 around 3500 RPM.
At 4000 RPM, the actual value is approximately 4-6° VOT (target is 15.4° VOT). The engine is misfiring and producing extreme smoke!
That is understandable .
When driven with a moderate load, everything works fine!

The car is not chipped. The pump settings are correct (timing is in order).
'Errors related to the injection molding process, outside of the normal tolerance range, are naturally stored in the memory.'

I will next remove the valve for the fuel injector and check the small filter to see if it is clogged. (The valve seems to be electrically okay so far.)
Unfortunately, the pump has to be completely removed for this job. You can't get it out when it's installed.

I don't have any other ideas at the moment.

What do you think about this problem?

Sure, here's the translation:

'Best regards,' or 'Sincerely,'.
Kim R.

Hi, before I remove the pump, I'd like to try measuring the internal pressure of the pump, as that controls the injection timing.

Could there be air in the fuel line, causing it to lose power at higher RPMs and form vapor bubbles due to vacuum?

Okay, for testing purposes, temporarily disconnect the suction hose between the filter and the pump, and let the pump draw diesel from a small container filled with clean/filtered diesel (ideally, also return the diesel to the same container).

If the engine then runs normally, the basic problem is solved.

How old is the fuel filter? Even workshops often don't see the need to replace it, but they still put it on the bill. (This happened to me at a Mercedes dealership in Kelheim.) Then, the car (DB280) starts acting up at full throttle, and everyone just shrugs their shoulders.
(The 280 is a gasoline engine, but the problem is similar. It can still get enough fuel at low consumption, but it can't get enough at high RPM.)

Otherwise, see my saying below: 'Measure first, then adjust - otherwise, you might end up having to pay someone else to do the adjustments for you.'

Look over there: https://community.dieselschrauber.org/en/viewtopic.php?t=5423