This study focused on assessing the performance of an agricultural diesel engine when using biofuel from Schleichera Oleosa (SO) with an engine tune-up in order to increase performance efficiency as well as reduce fuel consumption. The ANN model was used to analyze the tested data and estimate parameters, while the RSM model was used to increase the efficiency of the engine performance. The results of the ANN model showed that it was sufficient for predicting brake torque, brake power, and BSFC. The R2 of BSFC was less than the R2 of brake torque and brake power, leading to higher errors. The RMSE values for brake torque, brake power, and BSFC in the ID engine were 0.95 N-m, 0.154 kW, and 16.2 g/kW-hr, respectively, while the values in the IDI engine were 1.26 N-m, 0.211 kW, and13.8 g/kW-hr, respectively. Regarding the results of RSM optimization for the DI engine, the predicted values for the response parameters in accordance with the optimum operating parameters were 33.05 N-m of brake torque, 5.902 kW of brake power, and 436 g/kW-hr of BSFC. In the IDI engine, the response parameters were 30.93 N-m of brake torque, 5.261 kW of brake power, and 374 g/kW-hr of BSFC, following the optimum operating parameters.