Überschwinger Ladedruck Polo BLT TDI bis 2 bar (3 absolut) | Posts 16+

*knicks-mach*

Quote:

The curve of the second log of the VTG basic setting is no longer as smooth as the graph above.

Therefore, we are no smarter than we were at the beginning. The fact that the turbocharger builds up pressure was already known (no loss of power).

Whether the VTG (Variable Turbine Geometry) is being regulated correctly remains unfortunately hidden. In the idle state (default setting), the VTG is either fully open or fully closed. This has nothing to do with actual regulation.

We need LOG for 10 and 11, as written and in one piece.

If you'd like to provide us with a graphic, you can find an example here. It should look something like this:
/viewtopic.php?t=25869&highlight=ladedruck&start=24
(last graphic on page 2.)

To assess an overshoot, it's not only the overpressure that's important, but also the time factor, which allows you to determine how long the settling process takes.

Wurschdler wrote:

The curve of the second log for the VTG basic setting is not as smooth as the graph above.

For explanation: the actual LD value is in the boundary area between two diagnostic value levels, which is why the data jumps back and forth by 12 mbar, for example, due to intake manifold pulsations.

Hello,

Attached is the log file. Measurement blocks 10 and 11 were read out. The engine was accelerated from approximately 1200 to 4000 RPM in 3rd gear.

To be on the safe side, repeat the following three times in a row.

Well, a pressure regulation error of 336 - 374 mbar isn't that bad.
The MWB 10 test wasn't strictly necessary in this case, but it shows that the gas passages are neither noticeably blocked nor leaky in the boost pressure range. Attached are the logs, reduced to the essentials and with graphical analysis.

After the initial pressure buildup, the pressure is well regulated (with no signs of mechanical jamming), but then it tends to creep upwards again. This seems like a typical case that can be at least partially corrected by rotating the VTG rod further.

Quote:

After the initial adjustment, the pressure is well regulated (no signs of mechanical jamming), but then it tends to creep upwards again. This seems like a typical case that can be partially corrected by rotating the VTG rod for a longer period.

I completely agree, and it's not quite as dramatic as it seems. Aside from the brief spike, the LD (likely referring to a market indicator or system) is regulating relatively well.

Is this already a reason for a complaint?

In MWB 10: The accelerator pedal position that I generally want to see in relation to the boost pressure in other vehicles.

If you momentarily release the pressure, the target pressure will fall below the actual pressure .

Autoservice wrote:

In MWB 10 ---> Accelerator pedal position, which I generally want to see in relation to boost pressure in other vehicles. If the pressure drops even slightly, the desired pressure falls below the actual pressure

. Yes, that's a reason for fault code MWB 10.
However, the sampling rate is halved compared to using only the "11" setting, and therefore you might not even see the very high, short peaks.
Gas leaks can usually be clearly identified in the MWB 11 system, as the desired load (LD-Soll) typically drops briefly .

Okay, so it's not as bad as it seems...
First of all, thank you to Ulf and Autoservice, and also to the rest of you, for your assessments.

I don't really need to make any more claims with the dealer, unless there's something stored in the error memory that would trigger the warranty.

Me and the dealer are now like 10 best friends, if you understand what I mean .
Well, if the customer has to research the TPL (Third Party Liability) for the BLT (likely referring to a specific vehicle or component) themselves and then have to beg the workshop to fix it... I was even offered hush money to just accept the "shuddering" problem... but that's a different story... (They tried to tell me it was normal for that engine, but I was persistent!).

So, to put it simply, I would say that I'm not going to do anything about it for now, unless there's someone in this forum who lives near me, has a workshop, and is eager to adjust the VTG and work on a car with a warranty.

I personally believe that my intervention would only make the function worse.
I've never done anything like this before, and I have no idea how to do it.

Perhaps I should first acquire a similar loader that is broken to examine and understand its structure. If such a thing can even be found...

@Ulf: I'll send you another log file covering only MWB 11 later this week.

EDIT: Sorry, next time I will do what you suggest right away!