that yellow/blk wire is the main power circuit for the injectors and originates from the main relay beside the glovebox, the emulator blocks this by blocking out the positive supply of the injectors so that they do not work. the negative supply (ECU) trigger is never cut.
if you see positive voltage at the injectors this wire is OK, There is another symptom when the ECU fails, the injectors hang open as the the coupler constantly routes ground to the injectors as if the ECU were off, which when the key is turned on the circuit completes when the injectors get positive supply.
But please sort out the map sensor not being picked up as an error in the ECU, if that sensor input is not present, your ECU will never control any fuelling. Infact it should be backfiring too.