there is a rebic injector driver on ebay, extreemly retro 90's jap 'ecu' for a single injector
has map sensor
tacho input
injector duty cycle
basic as, it switches on at a certain combination of pressure and revs...
i was going to buy it for controlling water injection, helps with high comp under boost (chemical intercooling)
cleans the carbon out of the 'bustion chamber too...
whatever you do, an Air Fuel Ratio guage is a must (accurate,,,, wideband even)