Experimental investigation have been carried out to examine the performance, combustion analysis and emissions of a direct injection diesel engine coupled with electrical dynamometer fueled with diesel and pungam methyl ester and their blends (PME10, PME20 and PME30). From the investigation it is found that the combined increase of compression ratio, injection timing and injection pressure increases the Brake Thermal Efficiency and reduces Brake Specific Fuel Consumption while decreases emissions for PME20. For small sized direct injection constant speed engines, the optimum operating parameters combination was found as compression ratio of 19:1 with injection pressure of 240 bar and injection timing of 27°bTDC. The heat release rate is reduced for methyl ester of pungam oil blended fuel PME20 compared to diesel. The harmful pollutants such as HC, CO are reduced in pungam oil esters compared to diesel fuel. © 2015 Elsevier B.V., All rights reserved.