I thought injectors were 12v myself?????? The E-DIS isn't the same as the map sensor no. The E-DIS is the basic spark controller, then the ECU takes information from all the various sensors then calculates a SAW (Spank Advance Word) for the E-DIS and it will modify the spark timing accordingly. So in the event of a fault it should still start and run but performance and economy won't be at their best. (LOS mode Limited Operation Strategy)

The MAP sensor is a different means of doing the same job as cars that have a Air Flow Sensor.

Not too sure what else to suggest, im presuming its an XR2i yeah?