In this paper, the authors have evaluated reliability of four cylinder diesel engine by employing the Algebra of logics which is easier in comparison of old techniques. Here, a multi-component fuel system in diesel engine, comprised of four subsystems in series, has considered. The authors, in this model, have considered a parallel redundant fuel injective device to improve the system's performance. The whole system can fail due to failure of atleast one component of all the routes of flow. Boolean function technique has used to formulate and solve the mathematical model. Reliability and M.T.T.F. of the considered diesel engine have been obtained to connect the model with physical situations. A numerical example and its graphical representation have been appended at last to highlight important results.