An injection molding system comprising: a first selected valve, one or more downstream valves, delivering a fluid to a mold cavity, at least one fluid property sensor that detects a flow front of fluid material flowing downstream through the mold cavity at a trigger location within the cavity disposed between the first gate and at least one selected downstream gate, a controller instructing an actuator associated with the downstream gates to open the gates at a predetermined open gate target time on a first injection cycle, each valve associated with a position sensor that detects opening of a gate at an actual open gate time to the controller, the controller automatically adjusting time of instruction to open the gates on a subsequent injection cycle by an adjustment time equal to any delay in time between the predetermined open gate target time and the actual open gate time.