The article presents selected elements of the elaborated diagnostic testing method of marine diesel engine working spaces based on the energetic and spectral-correlation analysis of the course of the pulsating exhaust flow process in the channel powering a turbocharger. The investigations have been worked out within the scope of a realization of the research project No. 0T00B02129 funded by the Committee of Scientific Research. Conducting of an analysis of the diagnostic informativeness among the parameters characterizing the observed gas dynamic processes represented an essential methodological question of the project. A mathematical model, enabling simulations of well-known and recognizable engine working spaces failures as well as an entropy functions, as the measure of uncertainty of the set of identified states of the engine unfitness were applied for such a diagnostic purpose. Having evaluated the diagnostic information three diagnostic parameters were selected in the result of experiments of the numerical simulation. Thus, the adequate parameters of a technical state assessment of the marine diesel engine working spaces were chosen while there was no possibility to work out the cylinder indication (to create cylinder indicator diagrams). The conducted simulating investigations represented an introduction to the experimental investigations (to the diagnostic tests) of DETROIT DIESEL and ZVIEZDA engines that had been put into operation on the Polish Navy warships in recent years.