Hello, my name is Mark and I will try help you with this.
Ecu's are coded to the vehicle by VIN number and cannot be easily swapped over without reprogramming them.
What you need to do first is check the wiring and fuses to see why you are not getting the engine management light coming on.
It is possible that if a sensor wire has shorted to earth then it can cause the ecu to shut down to protect it.
If you have a tech 2, try using it to commincate with any of the other ecu's on the vehicle. If it can't then it could be a CAN bus or wiring fault.