Greetings companion. Before everything I want to tell you that I have no idea of the specific engine model that you speak, but however it handles a little knowledge of how the Ecus works, well, if it is true that so that the injection system works, some coss are needed, for me the most reelevants are: CKP CMP, MAF or MAP, oxygen iatr etc .. (CKP Chamkrasft: Sensors Camchaft Lev ...) It is also vital that you get in the electrical diagram and be a common line of direct current to the injectors (positive).
Almost sympats the Ecus work the Swicheo of the negative injection is to say direct posito to the inyertor by a common line and signal that is interrupted by negative to each of the mesheds, the supposed following the order of ignition and other things that also depend on the MAP or MAF sensor (air input) and the IAT (temperature).
I have repaired Ecus and the fundamental reason that she trbajen (the majority) in negative is to say: the signal that goes to the injectors, is because Amp is not handled in that way, if the case is that the ECU is reacted you have to check the wiring with magnifying glass, it does not use that you have pins even making bad contact and delivering amp (current, positive) to your lines of injectors.
Gustly if you wish, I could explain how ECU works and how you can determine (the case that you have no other to prove whether it really is ECU) if the power transistors of the PCM are bad or not.
Good luck and I hope you repair the vehicle ....