A method for controlling an internal combustion engine based on the amount of un-burned fuel dissolved in the engine oil, and returned into the manifold through the PCV valve as the engine oil temperature rises via adjusting fuel injection into a cylinder from a fuel injector, in a fuel delivery system. The fuel dilution in engine oil and the amount of fuel entering the intake manifold through the PCV valve can be determined based on one or more of oil volume, fuel composition (e.g., ethanol content), oil temperature, engine temperature, engine speed, engine load, engine run time, injected fuel mass, and exhaust gas composition.