@ Ulf VTG Mechanics

Hello Ulf,

I have a 1.4 TDI PD AMF engine. I'm having a problem in the partial load range, likely with the VTG (Variable Turbine Geometry) system (sporadically: the minimum boost pressure is not being reached).
I received the following tip from Thomas L. via email:

"Ulf has a method for making the VTG (variable turbine geometry) functional by adjusting it while the engine is running, moving it back and forth repeatedly. However, he doesn't remember the exact details and didn't save it because he no longer owns a TDI." But Ulf can definitely help you with that...

How does the "actuation" work? I'm having a really hard time accessing the VGT linkage on my engine.

Thank you for your help (you can also reply by email if I just missed it in the forum).

Regards,

Olaf.

Hi.

Quote:

. . . by aiming the VTG while the engine is running, it is then moved 100 times from stop to stop. . . How does the "actuation" work? I'm having a really hard time accessing the VGT linkage on my engine.

I built a rectangular wave generator that controls the turbocharger's boost pressure solenoid valve at approximately 1 Hz: on - off - on - off...
This allows the VTG to be adjusted incrementally as long as the engine is running and the vacuum pump is operating.

The exhaust flow blows away dissolved soot particles – especially effectively while driving and the engine is delivering power.
But no full-throttle rides, because the turbocharger boost is no longer regulated...!

The exhaust flow blows away dissolved soot particles – which is particularly effective while driving and the engine is delivering power.

The engine doesn't immediately switch to emergency mode, does it? Well, I guess it doesn't really matter anyway... What kind of current is used to power the solenoid valve?

Regards,
Olaf.

P.S.
Sorry for the silly questions, I haven't really done much experimenting with these switches before...

Quote:

Does the engine then not immediately switch to emergency mode? Well, it wouldn't really matter anyway... What kind of control current is used to activate the solenoid valve? Regards, Olaf. P.S. Sorry for the silly questions, but I haven't done many cool experiments with these switches yet...

Hi Olaf,

With a valve-resistor resistance of approximately 15 ohms, the control current is in the range of 1 ampere.
I haven't experienced any emergency mode issues so far (with my 1997 AFN). However, there is a noticeable fluctuation in acceleration starting around 2000 RPM, which is perfectly normal and indicates that the VTG (Variable Turbine Geometry) is actually being adjusted.