A swirl chamber automotive diesel engine was tested with five different fuels in order to evaluate the cold starting performance of Tar Sands derived diesel fuels which have higher aromatic contents with wider boiling ranges and lower cetane numbers. Higher aromatic content is expected to deteriorate the cold starting performance due to increased ignition delay periods; on the other hand low initial boiling point improves cold starting. Cold starting trials were performed in a temperature controlled cold chamber capable of temperatures down to −38°C. Extensive data were obtained for five fuels using two types of injection nozzles. Data presented include glow plug warm-up times as a function of temperature, engine cranking speeds at various ambient temperatures at which cold start attempts were made, and minimum starting temperatures and cranking speeds for different glow plug heating times.