well that is all i can suggest.Try it,what have u got to loose.
If ur running the new boost controller on the old solenoid then u have a problem.It theoretically shouldnt work because the controller will have nothing to hook into..
Turbo wastegate actuators are fed by the boost controller actuator and the boost controll actuator gets it's pressure from the inlet pipe leading to the plenum.Then the in cablin boost contorller gets it's vaccume from a plenum pressure source i.e: air con line leading to the carbon canister.or in ur case from the fpr pressure source.
Since i changed from the fpr pressure source to the air con carbon canister line pressure source i hold boost rock solid with no drop off.I also had to retune the controller once i found the new press source.I think that when it has an independant line for pressure and it doesnt share there is more room for accuracy,and,the unit has nothing else interfearing with it's signal vacume source.
hope that helps.
I am no expert.
See the pic in my first big post!!!!!!!!!!!