I have suffer the same issue with my injector C output, since more than a year of excellent working, my 3x board fail. I make some mods to my engine and my car keeps on my garage almost 2 months, then I start it and everything seems to be normal, just some adjustments that I have to make to my maps. When I was running my car to adjust my Fuel table, I notice that on low RPM ( less than 3k) the car sounds like one of my 4 cylinder was not working, and my car has a lot of smoke, so I start to unplug my injectors to detect the one, and I see that when I unplug #3, the car re-fines the idle, so I place a Led tester on it and it seems to be always on. Inmediatly I take off my MS from the car and connect the stim (ms board and the one for 3x board) and I test the Injector outputs, everything seems to be perfect, the 4 outputs blinks like my configuration is set, as Batch because I am not running sequential. so I tested my injector plugs again with the led, just to be sure that there is no shorts and the led is off, then y plug my MS into both hairness (MS3 and 3x) and the led becomes ON, just #3. SO my question is, Why the MS3xStimulator tells that everything is fine and when it is plugged to the hairness NOT???
Actually, because it is my daily car, I re-wire this injector to it's partner (injector D) to use my car, and it works perfect. just to take note of my issue.