1.9 TDI boosting when turbo is not connected

DomVom

New member
Joined
Nov 8, 2024
Location
Croatia
TDI
1.9tdi caddy
Hello,

I've recently cleaned the VNT vanes on my 1.9 TDI BLS due to an overboosting issue. The vanes were heavily caked and difficult to move. After reassembling everything, the car now runs poorly and produces a lot of gray/black smoke. It struggles to rev to 3,000 RPM, and sometimes even to 1,500 RPM. However, when I disconnect the VNT vacuum hose, the car runs normally and boosts as expected, which is puzzling. There are no fault codes present.
How vacuum hoses are currently connected: Could this be due to something I did during the reassembly, or could it be a faulty VNT actuator or N75 valve?
https://www.youtube.com/shorts/8cAjuWrNsdY
https://www.youtube.com/shorts/ljstZJmT0Zk
The engine is a 1.9 TDI PD (105 HP) BLS.

Thanks in advance for any help, guys!
 

DomVom

New member
Joined
Nov 8, 2024
Location
Croatia
TDI
1.9tdi caddy
I do have it connected like that, but the issue still persists. When the VNT vacuum is connected, the car becomes all lumpy, struggles to rev, and sometimes even shuts off. However, when the vacuum is disconnected, everything runs fine.

I did have the vacuum lines connected incorrectly at first. The car would run normally until it reached operating temperature, at which point it would go into limp mode and start smoking black.

Now it doesn't go into limp mode even when the operating temperature is reached and the VNT vacuum is disconnected
 
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