Circuit Description

Fuel Injector Balance Test is performed when a misfire, knock, excessive smoke, or rough running condition exists with no electrical Diagnostic Trouble Codes (DTCs). During test, Engine Control Module (ECM) turns OFF individual injectors while engine is running and scan tool displays engine RPM. If a fuel injector is turned OFF and there is a different engine speed change observed on scan tool when compared to other cylinders, that cylinder has a fuel injector or engine compression condition. If there is a balance rate of more than 4 mm³ or less than -4 mm³ on any cylinder, that cylinder has a fuel injector or engine compression condition. If a fuel injector is turned OFF and engine noise or smoke disappears, that cylinder has a fuel injector or engine compression condition.