Having the same problem mazda, two point two engine with azn, regulator and injector of course. Replace regulator and injector, And heists have a stupid filter in between the regulator to the injector replace that as well because it was leaking. Took mixer apart and cleaned everything very, very well. When I started up the large hose, which we call the slow path, From regulator 2 mixer shoots a burst oven L. P when turning ignition on. The injector does nothing. I can start it with some fluid and it will run. I can pull the injector out. It is not doing anything at any time. I see voltage at two wires, but not the third. ECU?