Ladedruck zu hoch (AFN) | Posts 32+

Okay, I finally managed to take the turbo apart... It was quite black, but everything seemed to be in working order... I just don't understand it! Why does the boost pressure go so high with the hose disconnected, even though everything seems to be okay?

Does this still make sense to anyone?


P.S. I wanted to buy the solenoid valve yesterday, but that part costs 80€!!! I thought it was supposed to be around 30€. Is there a similar one that can be used instead, which costs around 30€?
Or have they only slightly increased the prices?

I think you're changing too many things at once, and that's why you're not making progress. There are also far too many uncertainties involved here.

Attempt 1): Original charger with the pressure sensor disconnected. Read the pressure from the LDA (Lambda Probe) and from VAG-COM (to ensure your LDA is functioning correctly? Is the pressure hose properly connected?).

If that works, then put the other charger on and try the same thing again. You always need to be sure that what you're measuring is correct. As some people here have already said, the original sensor only goes up to 2500 mbar (which corresponds to a boost pressure of 1.5 bar). Anything above that, it gives inaccurate readings, and therefore the control unit cannot properly regulate the VTG. So, be careful about that. If this sensor is subjected to too much boost pressure, it could even theoretically break and stop working correctly!

If it was working reasonably well without the chip, it's clear that the chip has increased the boost pressure, and you're now entering a "red zone" where the control system is no longer functioning properly.

The LDA is working; in its original state, it reaches 1 bar of pressure, and when chipped (if it regulates properly), it reaches 1.5 bar.

I didn't have the original charger connected, but two GT1749VA chargers, because I thought the charger was broken.

Even without the chip, the top end performance wasn't always good, so there's definitely a defect somewhere, I just don't know where. Also, starting with the 4th or 5th gear, it would occasionally boost higher, but only up to 1.4 bar. At the time, I thought it might be due to the software, as it wasn't adjusted for the VA turbocharger.

Hello!

'I'm experiencing a similar issue with an A4 1Z that has been modified with a GT1749VA turbocharger. Additionally, it has a 300 kPa sensor and 0.232 injectors installed. Of course, the software has been adjusted accordingly.'
I had a problem with the tensioner pulley, which broke. As a result, the car was out of commission for about a week.
Since then, I've been experiencing significantly higher pressure spikes (up to 2 bar - with a target boost pressure of 1.6 bar, previously a maximum of around 1.85 bar).
Could it possibly be due to a slightly rusted VTG (Variable Turbine Geometry) linkage? I read in a thread that there's a way to move the VTG linkage to its respective end positions using VAG Com. Could someone please post a link or a brief guide for this procedure?
That would be very helpful (I can't find the relevant article or thread right now).
Sure, here's the translation:

'Thank you in advance!'