CBAB 2.0 TDI VW Tiguan Turbocharger Adjustment

Hello everyone,

I've been struggling for the past few days, dealing with issues like power loss, endless searching, and constant disassembly, all in an effort to get this car running properly again. What's fascinating about the whole thing is that there wasn't a single error in the system!

The first step of the operation was to replace the vacuum sensor (VTG). Optimally adjusted to 0.76 volts via VCDS, etc.

Feedback: No power output below 2500 RPM; above 2500 RPM, the engine starts making complaining noises, but then delivers full power again!

Step two: EGR valve cleaned + intake manifold flap (implausible signal) cleaned and servo motor replaced.

Feedback: The same as before...

Step three: DPF back pressure measured.

Feedback: everything is fine!

Okay, and now for the last step: I've searched through your forum and found something relevant – a post about adjusting VTG struts!

Upon further inspection during the reinstallation of the VTG (Variable Timing Gear), something seemed off: the adjustment screw on the linkage was significantly lower than it was before.

By pure chance!!! The turbocharger is missing the set screw for the pivot lever that controls the turbocharger wastegate.
Conclusion: The engine is building up excessive pressure in the exhaust system, and as a result, all values, such as AGR and air mass flow, are no longer correct.

Now my question: Can I install this set screw myself, or can I compare it to an identical turbocharger without causing any damage to the engine? Should I replace this now, or should I remove it and take it in for adjustment?

Thank you very much!
I only added the detailed description because it's almost impossible to find this error, let alone suspect it!

Hi,

What was wrong with the old vacuum tube?
Please provide pictures showing the installation location of the VTG adjustment lever on the loader, specifically where it connects to the mounting points. Depending on the charger, there may be physical stops or none at all.

Normally, the fully retracted or fully extended position of the vacuum actuator can be considered as its "limit" or "end point". However, it depends on the specific case, and be careful that the guide vanes do not touch the turbine wheel, especially in extreme conditions.

You are talking about 0.76V, so I assume the vacuum sensor has a position feedback. This feedback, as the name suggests, reports the position of the vacuum sensor. It does not report the position of the VTG adjustment lever. Problem identified?

If the vacuum sensor is not specifically designed for this loader: forget about it. The control of the VTG (Variable Turbine Geometry) depends on specific control paths and charging pressures, depending on the control method used. Even I, who could adjust the VTG parameters accordingly, would never think of doing that. If you can save hours or even days of work by buying the right component, it's simply foolish to waste time fiddling around.

Best regards, Rainer.