As diesel passenger cars become more popular in North America, more information is needed about low temperature fuel requirements.Two different make diesel passenger cars were tested in a temperature-controlled chassis dynamometer facility. The cars were started and driven using No. 2 diesel fuel (with and without flow improver additive) at a series of temperatures that included satisfactory operation as well as wax plugging and stalling. Simultaneous observations were made of fuel system temperatures and pressures and the vehicle’s ability to perform a driving-cycle test. Removal of a screen in the fuel tanks was found to lower the operability temperature substantially.