Given the increasing demands on engine components and the limitations of existing methods, research into a new system for monitoring the health of diesel engines is receiving a lot of attention. The primary goal of this research project is to use sound emission analysis to identify the air flow sensor malfunction. A diesel engine with four strokes was used for a number of experiments. Experiments conducted in a healthy operating environment yielded a comprehensive understanding of the source mechanisms involved in the typical generation of acoustic emissions. Time domain analysis is the method applied to identify account such as kurtosis, standard deviation, and root mean square (RMS) in this research. Monitoring these indicators enables to identify the early onset of breakdowns. A fault signature that could be used for fault detection and diagnosis, which was identified by comparing the monitored signal to that obtained under normal engine conditions.