Turbocharger actuators come in three styles, a brief description of each is provided below:
Pneumatic actuators work from the air pressure in the inlet manifold. When it gets to a preordained limit the actuator opens and allows some exhaust gas to pass or waste away from the turbine wheel. Slowing down the turbocharger speed and boost. These style actuators are very prevalent and there are many different part numbers. The common fault on these units is where the actuator diaphragm splits and the actuator does not work. They are hard to repair but fortunately a new actuator is not too expensive. Turbotech can supply most part number actuators.
Electric actuators are controlled by the engine computer and set the variable vanes or the wastegate in required positions to control the speed (boost) of a turbocharger. They are more responsive than pneumatic actuators. They are somewhat easy to repair but parts are hard to find and they cannot be setup without specialised test equipment.
Turbotech has all the necessary test equipment and you can call us to get a quote on electric actuators. If we cannot repair yours we can give you a good quote on a new unit.
Stepping motors are a brushless DC electric motor that divides a full rotation into a number of equal steps. The motor's position can then be commanded to move and hold at one of these steps without any position sensor for feedback. These are used to position the turbochargers variable vane in a required position. These units are cheap to make, as well as being durable and reliable. To set them up requires a proper electronic master test device. Turbotech has these devices and we can give you a quote to replace your stepper motor.