Do you know if it's an OBD1 or OBD0 ECU? OBD1 has 3 gray plugs, and OBD0 has one black plug and one green (or natural nylon color)... There were PR3 ECUs in both OBD generations, so finding out which one you have is the first step. By the way, why do you want to replace it? That's a great ECU, it's the JDM B16A ECU, and a nice find..