This dissertation presents the optimization of injection pressure and injection timing of the compression ignition engine. By modifying the two parameters of an engine as injection pressure and injection timing, and engine performance has been observed and data was collected. On the basis of data, many graphs have been drawn between compression ignition engine Load and various performance parameters that are collected such as Indicated Power, Brake Power and specific fuel consumption (I.P., B.P., and S.F.C.). By advancing and retarding the injection pressure as well as the fuel injection timing, several data has been collected. By analysing and recognizing the obtained data from compression ignition engine modification and enhance the situation of injection pressure and injection timing had been done. On the other hand, the fossil fuel or conventional fuel blended with the biodiesel has been done by the fuel modification process. I have used Jatropha seed because it will be easily cultivated with less amount of water or in a dry place. The Jatropha biodiesel blended with diesel for C.I. Engine. B100 (It means that 100 percent biodiesel) biodiesel are used to determine the engine performance on different load. The 2-stroke single cylinder C.I. Engine has been tested with B100 blended fuel. First of all, the engine runs on no-load condition for half an hour time for the test to obtain the real operational condition of an engine. Some blends having high exhaust gases emission such as SOx, NOx but also having high B.P. reading, on the other side some blends having fewer exhaust gases emission of SOx, NOx but also having less B.P. reading. I had made many comparisons between performance parameters and a load of the engine. I have made a conclusion that B20 blends are good in all prospect whether it is exhaust gases emission or engine power. The Jatropha plant can evoke in infertile land so that we can cultivate the Jatropha in those types of areas. So farmers can utilize their infertile land and earn money for their excellence. In the present situation, Jatropha oil are costly as compare to diesel but when the cultivation takes place on the commercial level. The cost will decrease and also do not forget that we have limited conventional fuel for the future generation.