The U.S. Navy is attempting to reduce dependence on conventional diesel fuels as a part of the environmental initiative commonly referred to as “The Great Green Fleet”. The purpose of this research was to characterize the measurements of ignition delay gathered by the Advanced Engine Technology Ignition Quality Tester (IQT) with conventional Navy diesel fuels, pure component biodiesel fuels, primary cetane standards, and toluene-hexadecane blends. The use of computational analysis with pressure traces gathered from the IQT allowed for the comparison of IQT ignition delay results with various methods of calculating start of combustion for various fuels. Physical and chemical ignition delays of each fuel were also calculated using different separation techniques and the chemical ignition delay results were compared with prior academic literature and with chemical ignition delays calculated with Lawrence Livermore kinetic theory.