Here is a look at the control systems of the sequential turbo system and the problems that may occur. Hopefully it will help out with a common set of problems.   There are a series of attached pictures which show where all the components of the sequential system are located on the engine. They are indicated by a number - look at the pressure map for a key to these numbers and their logical position in the system.   Actuators and VSVs:   There are four VSV/actuator assemblies that control th