A unique, temperature controlled, single-cylinder engine test facility was designed and constructed to simulate cold starting of a car engine. The temperature of the coolant, oil, fuel and air used by the engine can be individually controlled to -29°C. Moreover, the engine is enclosed in a temperature controlled insulated chamber. With this facility the conditions that occur in a car engine as it cranks and starts, can be quickly duplicated and maintained for detailed study.The supply equivalence ratio values for starting the engine were determined using either gasoline with port fuel injection or propane as a premixed charge. For gaseous propane, the supply equivalence ratio for starting was nearly constant at all temperatures studied. However, for gasoline the supply equivalence ratio for starting increased as the temperature was lowered. The significance of these findings is discussed.