Wastegate Diaphragm
WARNING: This page does not describe the selected car, but rather 35 other vehicles, including the 1992 Pontiac Trans Sport, 1992 Oldsmobile Silhouette, 1992 Oldsmobile Bravada, 1992 GMC Yukon, and 1992 GMC Vandura Special. However, it is still accessible from the selected car via links, so may be relevant.
Disconnect hose from wastegate diaphragm (actuator). Connect a radiator pressure tester to wastegate diaphragm fitting. Actuator should start to move when approximately 5 lbs. of pressure have been applied to diaphragm and reach full travel at 15 lbs. of pressure. Internal diaphragm return spring should return diaphragm when pressure bleeds off.