Starting Problems MB 290 TDI

Hello,
I'm going to post a question here on behalf of a friend...
(He seems to be having trouble signing in.)
Perhaps someone can offer some assistance.
Thank you in advance.
Best regards, Rodion.



Hello everyone,

As a 'G' driver, I'm asking here because we're not making any progress in other forums.
We have a tendency to bog down when starting from a low RPM.
When starting, the engine revs up very slowly. Once it reaches over 1500 RPM, it continues to rev normally, the turbo kicks in as expected, and the vehicle drives normally.
The problem mainly occurs during the initial acceleration phase, which can quickly become an issue when approaching intersections or driving uphill (where a lower gear may need to be engaged).
You're pressing the accelerator to the floor, the transmission is in 'D', but the engine is only revving very slowly. The transmission engages correctly in first gear.
The problem has now occurred for the second time after 3 months.
At that time, we identified the pressure sensor (001 542 07 17), which is located above the intake manifold and connected to it via a small hose, as the cause. At least, we thought so. This small hose was clogged with oil sludge from the exhaust gas recirculation system.
After ruling out other causes (replacing the diesel pre-filter, cleaning the air filter, replacing the main diesel filter) and confirming that the small hose to the intake manifold was clear and unobstructed, I suspect the problem lies directly within this switch.
Furthermore, we are excluding the AGR, as it is decommissioned and closed.
The wastegate was checked as far as possible from the outside. It operates smoothly and is in the closed position.
Would a fault in the wastegate also cause problems at engine speeds below 1500 RPM, or not?

Question: At what point does the turbocharger start to build boost? What is the intake pressure when the engine is idling (i.e., not under load)?

Sure, here's the translation:

'Thank you very much in advance!'

Best regards, Mario.