The objective of our research was to diagnose the technical status of different models of internal combustion engines with provoked ignition, in order to detect premature failures and propose a maintenance control. Data was collected through an exhaust gas analysis carried out on different types of vehicles between April and August 2023 at the Faculty of Energy of the National University of Loja. Traditional methods such as compression testing, measurement of harmful substances in exhaust gases and analysis of signals from on-board diagnostic systems were used in order to diagnose the technical condition of the engines, based on the Official STANDARD. Mexican NOM-041-SEMARNAT-2015, complying with the protocol for measuring and obtaining gas data through the gas analyzer model CAPELEC3201, as well as the G-scan 3 scanner and Hanteck 6022L oscilloscope. The test results obtained have been verified during the operation of the engines and maintenance checks. Twenty units were randomly studied and several causes of failure were found, such as: damage to the lubrication and cooling systems, failures in the injection and distribution systems, as well as manufacturing defects.