Tuning Box for late model Common Rail injection system. This system connects to and controls the individual injectors (contains 4 or 6 injecto Drivers). This unit is supplied pre-programmed, and is simple plug-in installation unlike some other systems, it does not require an additional TPS signal. This unit self calculates via the received injection pulses. Some engines, expecially the 4 cylinder Japanese Common Rail engines. respond better to control of hte injector duty cycle (open time). This unit allows high power out put to be achieved on these engines, without increaseing the demand on the High-Pressure Fuel Pump. Some tuning companies do not have a similar unit in their range, and find they need to de-tune their CRD style units to avoid triggering the vehicle "Check Engine" systems. when the High Pressure Pump, is unable to meet the additional demond.