To evaluate the performance and emissions of a diesel engine fuelled by biodiesel blends produced from polanga oil, the engine was run to investigate the effects of injection pressure and timing on engine operation with varying biodiesel blends concentrations. Consequently, commercial diesel fuel blended with different polanga biodiesel in different percentages (0%, 10%, 20%, 30%, and 40%). The average reduction in the thermal performance of the biodiesel fuels, was reduced proportionally with the biodiesel blends. B20 blend operates closest to that of diesel oil whereas, the engine operated with any higher injection timing, ranging from 27 to 31 degrees bTDC, the emission constituents of CO, UHC, CO2, and smoke are the least and remains constant in the injection timing between 27 to 31 degrees bTDC. Polanga based biodiesel blends provide a better result at an injection timing of 31 degrees bTDC and injection pressure of 240 bar leading towards minimum emission. Up to 20% polanga biodiesel blends improvement in the engine performance and reduction in the emissions was observed without any modifications to CI engine.