Bleach is the killer of the injectors it eats the springs, stainless steel balls and orings up. Many times the oring will get sticky and the ball will stick to it when you go to high pressure. you can free it up with a pick through te barb opening and it may work for a while. Otherwise try removing the barb and check if the oring or spring is worn or gone (dissolved). you can try removing the oring and flipping it, sometimes that will get you by until you get an new one or a repair kit. another common issue is the orifice will loosen up in the body. They are usually installed with an allen wrench or a flat head screwdriver. make sure it is installed all the way and tight in the body of the injector (vibration will cause them to back out on some) . Also like mentioned check the spring and the venturi cavity for any debris. a small piece of Teflon tape, string or plastic can stop it from working. If you run a lot of bleach you can also try and clean it out in some mild acid to remove the rust and corrosion which can help as well.
