Fuel Injector Functional Test
- If the engine will not accelerate smoothly and idles roughly, a fuel injector may be inoperative. To check for a faulty injector, first bring the engine to operating temperature. With the engine idling disconnect and reconnect each injector while noting any change in idle speed.
- When a good injector is disconnected, idle speed should drop and then recover when the injector is connected. If an injector is disconnected and no change occurs in idle speed or quality, a faulty injector is indicated. See Fig 1 .