Note. The boost pressure control valve works in the opposite way to conventional boost pressure control valves.
If there is no control pressure, the boost pressure is limited.
Check the tightness of the connections between the vacuum pump and the boost pressure control valve.
Checking the calibration pressure
It is carried out on cars with the F9Q 754 engine.
Use the indicator on the magnetic stand. An indicator is mounted on the stem end of the boost pressure control valve of the pressure regulator (as close as possible to the axis of the boost pressure control valve).
Gradually build up vacuum at the boost pressure control valve using pressure gauge Mot. 1014.
Attention! To check the calibration pressure on the F9Q 750 engine, the turbocharger must be removed.