Hi! My 91 Honda Civic hatchback (manual trans, 4-speed) will only starts when the main injector is unplugged. it is a throttle body fuel injection system and the car has two injectors (main and auxiliary). Also, it wouldn't start if the noid light is plugged into the main injector harness (after unplugging it). I checked the resistances of both injectors and they are okay. A mechanic told me to clean the main injector and try. I took the main injector off of the throttle body and tested it with a 9V battery and heard a very light click sound using a stethoscope every time I connected it with the battery. Any idea what is wrong with it? Thanks.