Boost Pressure Drop During Acceleration: Causes?

Hello everyone!

I've been reading this forum for several months now, and I'm really impressed!

'Due to occasional power fluctuations in my car, I was just about to start...'
Install a boost gauge.
'To do this, I removed the pipe located behind the outlet of the intercooler.'
I wanted to drill here and tap into the pressure.

My problem:

The inside of the pipe is oily in some areas and contains small particles that appear to be able to be crushed.

Does it have to be like this


For your information:
The engine has only 40,000 km on it. The turbocharger is dry from the outside.
Here's the translation:

'This refers to the ZD30DDTi engine in the Nissan Patrol Y61.'
3-liter direct injection engine with a variable geometry turbocharger from Garrett.

Thank you for your help.

Greetings,
Alex.

nissandiesel wrote:

The inside of the pipe is oily in some areas and contains small particles that appear to be able to be crushed. Does it have to be like this

I would consider that normal for TDIs.
I've also found very small, soft crumbs (less than 1 mm) and some oil in the intake manifold in front of the turbocharger, where the crumbs are sitting in the "grooves" of the aluminum surface.
Apparently, all of this stuff comes from the KGE.

As long as you're not experiencing excessive oil consumption, I wouldn't worry about it.

Thank you, Ulf, for your quick response!
(Even though mine is a bit late...)

I've been having problems with the engine for quite some time.
When accelerating in the middle range, it only pulls with some delay.
In the RPM range of 2000 to 2300 RPM, there's hardly any power output.

With the installed boost pressure gauge, you can now precisely monitor it.
Regardless of the gear selected in the automatic transmission, when I press the accelerator to accelerate, the turbo boost pressure drops.
It first decreases and then gradually increases again.
For example, on a country road, at a speed of approximately 80 km/h and 1900 RPM, the boost pressure is about 0.8 bar.
When you press the accelerator, the pressure drops to 0.3 bar and then slowly increases to 1.2 bar.
The whole thing takes about 4 seconds. It's not exactly fun when you're trying to overtake.

This is also the case on the highway, even with a bypass capacitor.
At 110 km/h and 2300 RPM, the pressure is approximately 0.9 bar.
Should I now accelerate without triggering the converter bypass?
The boost pressure (while accelerating!) slowly drops to 0.3 bar.

I initially thought the problem was with my boost gauge.
However, the measurement taken with a borrowed display from the workshop has...
Results confirmed.

When accelerating from a standstill, the boost pressure increases to approximately 1 bar and then decreases.
depressurize to below 0.3 bar. After the initial drop, it then rises to 1.3 bar and then falls again.
It stabilizes at approximately 1 bar and then oscillates (0.9 ... 1.1 bar).

What could possibly be the reason ?

Greetings,
Alex.

Check if there's a leak in the system; you often hear a distinct hissing sound.
or if your vacuum pump from the turbo (I'm not sure exactly how it looks in that car).
works correctly.
Perhaps the dealer can test whether the boost pressure control system is working correctly.

Dieselmike.