My advice would be to remove dv,block the pipe(broom handle size) and try that.If still no boost by pass the amal and try that but dont go mad because it will probably over boost.Yes the diaphragm can split but surely you would here the air escaping when it trying to build up boost.Mine used to run at 22-24psi,amal valve packed up and it resorted to about 10-12psi=shit slow lol.