I'm at my wit's end: Intermittent power loss on a 1Z TDI

Hello everyone:

"I occasionally experience noticeable power loss when running with reduced boost pressure, and I would appreciate any helpful comments."

Problem: Most of the time, the bus runs very well. However, under load, the boost pressure briefly rises to 1.2 bar and then quickly regulates back down to 0.9 bar within 1-2 seconds.

"Occasionally, about every fourth traffic light, I experience a noticeable loss of power. The boost pressure doesn't exceed 0.6 bar until I reach engine speeds above 3,200 rpm. Then, the boost pressure briefly spikes to well over 1.2 bar, and I have full power, and everything is okay again, until the problem repeats itself."

Vehicle: VW T3 Bus with 1Z TDI engine, chipped to 110 horsepower, with a new turbocharger, new magnetic valve, and a cleaned mass airflow sensor (Pierburg). The EGR valve is sealed with a plate.


So far, I've tried:
1.) I thought the Westgate valve was stuck, so I replaced the Tubor, but it didn't make a difference.
2.) Replaced the LMM (lambda manifold manifold), but it didn't change anything.
3.) New solenoid valve, doesn't change anything.
4.) Error memory, empty.
5.) The hoses appear to be okay.
6.

What should I check next?


Thank you very much.

Lukas.

habe unlängst das selbe Phänomen gehabt, es war dann die die verendende Batterie. Wie schaut den die Spannung bei Zündung ein aus? Bei mir ist eine Zelle der BAtterie auf sporadisch Plattenschluss gegangen, zum Starten hat es etwa seit Auftreten des Leistungsverlustes(kein Ladedruck) noch rund 12Tage gereicht. Ich habe dann mal das Standardprogramm gemacht, und beim Messen des Spulenwiderstabdes vom N75 (Soll 25-45 Ohm) die Spannung bei Zündung ein mit 10,8Volt gemessen. Zum Starten reichte es allemal aber irgendwie kam das Steuergerät dabei aus dem Tritt. Es kam kein Glühwendel der Motor verhielt sich unauffällig bis auf den fehlenden Ladedruck halt. DrI didn't try any "ehzahlorgien" (I don't know what that means), but after checking the electrical system, I replaced the battery.rt and since then everything has been working normally again.

Best regards, Robert.

Thank you.

I'll take a look at that.
I replaced the battery a few months ago, but I no longer remember whether it was the starter battery or the auxiliary battery.
Lukas.

I was never able to fix the problem until recently, when I replaced the nozzles.
Since then, the problem has been gone.
I'm guessing it's the needle valve actuator?
Do you think that's possible?

Regards,
Lukas.