1. Loosen the fasteners securing the valve cover nuts, then remove the nuts, the cover, and the gasket.
2. Remove the sleeve and clamps from the valve.
3. Position the timer as shown in the figure, so that the timer’s stem rests on the flat part of the valve.
4. Reset the clock.
5. We apply pressure to the valve.
6. Once the gauge reads the displacement specified in the tables (see the exploded view in the Garrett T-Series catalog), record the pressure and check that it falls within the required range.
7. Release the pressure and check that the gauge returns to zero.
8. If the pressure is incorrect, the valve must be replaced.

Running an engine with an improperly calibrated turbo valve can result in a loss of power or serious engine damage.