The funny thing is i can drive the car with the Vacuum pipe off the turbo still late boosting but not that bad and the power is good too but not for long
ah ok, this does not sound good.. it sounds like the vanes are not moving at all.
think of it like this :
the idea behind the vnt is that the ecu controls the turbo via a actuator that varies the vacuum to the vnt controller, pulling the arm in or out, which changes the angle of the vanes.
when the vanes are closed, the turbo acts like a "small" turbo, spinning up quickly , boost from about 1200rpm.. as rpm climbs the ecu opens the vanes thus the turbo acts like a "bigger" turbo causing less backpressure.
if you say that it makes no differance if the vacuum is connected or not, it can only mean that the vanes are always in the full open condition , because this is the fail-safe condition. thus the fault could be :
no vacuum reaching the actuator, actuator itself bust, wiring to actuator bust, or the vanes are stuck..
try moving the controller arm by hand, it is spring loaded but it can be moved. if it cant be moved they might have screwed up with reassembly. pull the vacuum pipe going to the arm controller off and feel for vacuum with the motor running.
http://www.realoem.com/bmw/showparts.do?model=AL72&mospid=47634&btnr=11_2230&hg=11&fg=45
if you look at the pic, number 1 is the actuator im talking about, and the pipe number 12 leads to the canister which controls the vnt arm.
lastly it might still be a good idea to check for error codes, it might be something totaly unrelated thats bust, forcing the ecu into limp mode, where the ecu will also not allow the turbo to boost..
hope this helps :dunno:
