Bio-ethanol fuel has been used widely in spark ignition engines because it owns similar properties as gasoline fuel. Ethanol fuel is characterized by higher heat of vaporization value in comparison with conventional gasoline fuel, 840kJ/kg for ethanol and 270kJ/kg for gasoline. As a result, when using pure ethanol as fuel for engines, these properties contribute to the lower temperature of intake mixture then effect engine operating, especially at cold starting and low embient temperature condition. In addition, low temperature of mixture will contribute to an affect onthe stability ofidling condition. In oder to improve the performance of the engine fueled with pure ethanol at cold starting and low ambient temperature condition, an electric heating system had been designed for a port fuel injection engine.The studyresults show that, with the heating system, the test engine could be started easily at cold start and low embient temperature conditons. In addition, cold idling speed of the test engine is more stable than that of the original engine