A single wire fires all the fuel injectors at once, and it carries quite a bit of current. It goes through the large round connector in the aquarium, near the windshield wiper motor. I had some trouble with corrosion in my connector. Because of the high current requirements and the corrosion problems I'd had in the past, I decided to bypass the connector for that circuit. The fuel injector wire is the large green and red one (14 gauge, I think). There's another smaller green and red wire, so make sure you get the larger one. I put a spade-type disconnect in the bypass wire.
