The results obtained from the recently performed investigations show that the VIT positioning unit moves in and out with each injection under the forces in the fuel injection pumps. Subject movement can have a peak-to-peak amplitude of up to 1.5 mm and eventually results in excessive wear on the positioner's feedback transmitter. To make this system robust against these small but frequent movements, that have to be accepted and shall be considered normal for this arrangement, a backlash of 2 mm was introduced between piston rod and feedback potentiometer. The resulting loss in positioning accuracy stays within the acceptable tolerance for the VIT system. In addition the solenoid valves were changed to a rigid design based on the experience with sticking valves of the previous design. However, those internal changes are not essential on all engine types and trouble-free operation of the original VIT has been experienced in many installations.