Biofuel is a viable substitute source of energy for diesel vehicles due to its greater physio-chemical properties. The biofuels used in this study is synthesized from pumpkin seed oil using the esterification reaction technique. The biodiesel was synthesized under ideal conditions and was employed to evaluate the impact of injection pressure varying from 200 to 275 bar in 25 bar increments and was tested for its effectiveness, combustions and the emission performance of 1 cylinder, 4 stroke DI diesel engine at a regular momentum of 1500 rpm using 25% Pumpkin seed biodiesel (PSBD25). The outcomes demonstrated that the BTE of PSBD25 be raised by 1.68 %, with decrease by 6.5% BSFC, the release of CO, HC, and smoke were diminished by 57%, 33% and 36% respectively, but NO emissions were boosted at higher IP of 250 bar by 18.5% compared to the standard IP of 200bar. Pressure in the cylinder and heat release rate for PSBD25 were increased, but ignition delay was shortened when compared to PSBD25 at standard IP of 200 bar. It is concluded that, there is a greater progress in performance and ignition features, as well as a reduction in exhaust gas release for PSBD25 with the exception of NO emissions at 250 bar IP at maximum load conditions.