High Boost Pressure, ASZ Engine

Hello,
I used the search function, but unfortunately, I didn't get any useful results.

My problem is that for about a week now, the boost pressure has been too high when I'm driving at full throttle.
Therefore, I had the MWB11 unit read out at a friendly service center.
A test drive was conducted using a diagnostic device, with a speed range of 1500 RPM.
I drove for 3000 miles in 3rd gear (with the accelerator fully pressed).
He pressed a flyer into my hand at booth 3150.
shall = 2478 mbar
Air pressure: 2983 mbar. Touch response: 93%.
He said the LD (likely referring to a pressure or temperature reading) is too high, but it's not causing any errors and the system isn't going into emergency mode.
I was told to just keep driving like this (since everything seems to be working), or to have the turbo replaced (but he couldn't explain exactly why).
I have now read several technical articles and used the 100ml syringe to check the VTG for consistency.
Ist i.O. läst sich leicht regeln bewegt sich schon bei ca. -100mbar unterdruck richtung Druckdose. Doesn't stutter either.
Vacuum hoses are also sealed.
Vacuum pump tested, achieving a vacuum pressure of -0.9 bar.
When I accelerate normally (not full throttle), I see on my display that the turbo pressure increases to about 1 bar and then settles down to around 0.7 bar, which is perfectly normal, as it always has been.
It only reaches 2 bar (no overshooting) when under full load.
I'm worried that my ATL is going to be destroyed.
Could it be an LD control valve?
The exhaust gas recirculation system has been deactivated for over 100,000 kilometers.

Engine ASZ.
142,000 km
Year of manufacture: 09/2001.

Greetings from the Palatinate region.

Hello,

Quote:

He said that the LD is too high, but he doesn't make any mistakes and doesn't go into emergency mode either.

This is because the emergency mode only activates after a certain period of deviation from the boost pressure regulation, for example, 4 seconds.

Quote:

I'm worried that my ATL will be dismantled.

Absolutely justified, because with these deviations, the loader can be disassembled at any time.
Until the repair is possible, it is essential to avoid using full throttle.

Regarding the error itself, the search function provides more than enough information. In short, the most common cause is either replacing the charger or cleaning the VTG (variable turbine geometry). Check or replace the magnetic valve responsible for controlling the boost pressure.

Common causes of jams:
- overly cautious driving style.
- too much constant high speed.
- poor tuning
- Leak in the charge air cooler or problems with the EGR system, excessive exhaust smoke, VTG stuck.

Best regards, Rainer.

w123diesel wrote:

pressure= 2478mbar

. However, it doesn't have a standard ASZ (altitude sensor). Who did the tuning?

Sorry, I forgot to mention.
[Edit Admin: xxxxxxxxxxxxxxxxx]
Power increase to 170 horsepower.

From 1500 RPM to 3000 RPM, the time is significantly more than 4 seconds.
At 1500 RPM, the full load is not yet reached.

Best regards, Jürgen.

w123diesel wrote:

Sorry, I forgot to mention. [Edit Admin: xxxxxxxxxxxxxxxxx] Power increase to 170 horsepower. From 1500 RPM to 3000 RPM, the time is significantly more than 4 seconds. At 1500 RPM, the full load is not yet reached. Best regards, Jürgen

If the 170 horsepower is not just a number on paper, it should be noted that achieving this with the installed turbochargers/superchargers without producing soot is hardly possible. So, if the 170 horsepower is not a fabrication: This is likely the cause of the turbocharger problems now.

Unfortunately, exaggerating performance figures is very common in the tuning industry, as 95% of customers, lacking sufficient technical knowledge, tend to go for the highest advertised performance at the lowest price.

VG, Rainer.

A performance diagram was created on a dynamometer at company xxxxxxxxxxxxxxxxx and provided to me.
It is a reputable company.
Definitely, the error has nothing to do with the tuning modification, which was done years ago.
The fact is that the increase in LD levels has only been occurring for a week.

Best regards, Jürgen.

A performance diagram was created and handed to me by the company xxxxxxxxxxxxxxxxx during testing.
It is a reputable company.
Definitely, the error has nothing to do with the tuning modification, which was done years ago.
The fact is that the increase in LD levels has only been occurring for a week.

Best regards, Jürgen

Yes, I have seen these 'diagrams' before. They were from various vehicles. They looked very nicely painted, and ALL of them had the same values in identical vehicles.

Quote:

In any case, the error has nothing to do with the tuning modification, which was done years ago.

Again, we're not just making things up because the weather is nice. I can confidently say that I know what the G4 hardware can and cannot do, based on the specified values.

As mentioned before, there are exactly 2 possibilities:
- The 170 horsepower is genuine, but there's an increasing amount of oil leakage, and in the long term, the VTG (variable turbine geometry) will likely become clogged.
- The 170 horsepower figure is not accurate; the car doesn't perform any better than the standard version, and the VTG (Variable Turbine Geometry) isn't sticking for this reason.

You can decide which of these applies to you.

VG, Rainer.

Hello,
I removed the turbocharger and checked the variable geometry turbine (VGT) adjustment mechanism for smooth operation.
Two guide vanes were stiff and jammed, thus blocking the adjustment ring that moves all the guide vanes.
Not because of the Russian model, but because a scratch (or indentation) formed on the casing.
I cleaned everything thoroughly and removed the burr using 1200 grit wet sandpaper.
I also lightly sanded the side surfaces of the guide vanes with 1200 grit sandpaper, ensuring that there were no scratches or burrs visible anywhere.
So, everything is flat and clean.
Everything was reassembled, checked for smooth operation, and installed in the car.
And behold, it's working again as it should.
I took some pictures.
How can I set this up, if anyone is interested.

Best regards, Jürgen.

Hello!

Thank you for the feedback!!
Of course, we are interested in pictures!

Click on the "Upload" section on the homepage.
You can upload your images there and then link them here, so that they appear directly in this thread.

Best regards from Munich!

Here are the photos.
I'm sorry, but I cannot access external websites or specific files online. Therefore, I am unable to translate the text from the provided URL.
In photo 4670, the perpetrator is visible at the 4 o'clock position (strong reflection).
The number 4668 at the 2 o'clock position corresponds to the same guide vane that has become lodged against the housing.

Hello and thank you for the photos!

It looks like it's definitely overheating damage, where the VTG plate has warped.
Could that be possible?

Best regards from Munich!

The VTG record is perfectly flat, with no signs of warping.

Well done, you didn't remove the plate. In the second picture, inside the exhaust housing, yes, that one comes out; it's about 5mm thick. Often, rust forms behind it, which reduces the distance to the turbine blades. I also don't understand why a plate is still installed in these turbocharger types. Perhaps it's a different material, or has something to do with thermal expansion. In a disassembled GT1749VB turbocharger from a 2004 vehicle, there is no intermediate plate installed.