This is only a guess without a schematic of the ECU. Each fuel Injector should have one transistor to control it, so there would be 4 identical (Darlington) transistors (usually NPN type). The control chip sends a pulse to the Base of each transistor to turn it on (like a switch) and cause current flow from the Collector (+) to Emitter (-). The Emitters of the two transistors in the photo are grounded through a current limiting resistor. The big resistor that fried. The Collector of each transistor will connect through the socket to a wire going to its injector coil. The other pin of the injector coil connects to 12v. In the burned section is one of those transistors so there should be 3 more with the same part number.
Again, I'm guessing, but the photo shows the common thing between two injectors would be the supply voltage and the grounding resistor for the two transistors.
If you can, follow the traces from each transistor Collector (the center pin that sticks out from the other two) to the connector socket pin and see what color wire is on the plug. It will match the color on an injector plug.
Also check the ground wires on the connector. You can see the two Emitters are connected together and go to the big resistor. The other end of that resistor might to to a pin on the plug for a ground.
Different name for the same unit. ECU, ECM, MPFI, SPFI.