HI,
With the manual boost adj, have you still got the amal valve in place,
if so check your pipe's from the turbo to the valve are correctly fitted.
also starting from scratch, the pipe that comes from the compressor of the turbo,
put it straight to the actuator, and see what the boost pressure is, it should show
the actuator pressure, if so , you have a problem with either your manual adj, or amal valve.

DAVE R.