Abstract: The invention relates to a method for diagnosing the operational state of a fuel supply system of an automobile internal combustion engine, said fuel being stored in a tank of the vehicle and having a variable alcohol content, wherein said method includes a step of diagnosing (S6) the operational state of the fuel supply system, a step of detecting the addition of alcohol into the tank (S2), a step of determining the alcohol content (S2bis) in the fuel, and a checking step (S4) in which the diagnosis step (S6) is triggered if the step of determining the alcohol content (S2bis) in the fuel is completed.

Abstract: A method for diagnosing a condition of a system for supplying fuel to a fuel injected controlled-ignition internal combustion engine, of a type including an electric control device that makes use of an oxygen probe for closed-loop regulation of a value of an air/fuel ratio admitted to the combustion chambers of the engine, and according to which a signal delivered by the oxygen probe is analyzed, the method a) deducing from the signal a change in injection time correction factor ALPHACL_MEAN making it possible to regulate richness of exhaust gases leaving the engine; b) comparing ALPHACL_MEAN against predetermined minimum and maximum threshold values THRESHOLD_MIN and THRESHOLD_MAX; c) diagnosing a defective condition when ALPHACL_MEAN is outside of a window included between THRESHOLD_MIN and THRESHOLD_MAX.

Abstract: The invention relates to a method for diagnosing the operational state of a fuel supply system of an automobile internal combustion engine, said fuel being stored in a tank of the vehicle and having a variable alcohol content, wherein said method includes a step of diagnosing (S6) the operational state of the fuel supply system, a step of detecting the addition of alcohol into the tank (S2), a step of determining the alcohol content (S2bis) in the fuel, and a checking step (S4) in which the diagnosis step (S6) is triggered if the step of determining the alcohol content (S2bis) in the fuel is completed.

Abstract: A method for diagnosing a condition of a system for supplying fuel to a fuel injected controlled-ignition internal combustion engine, of a type including an electric control device that makes use of an oxygen probe for closed-loop regulation of a value of air/fuel ratio admitted to combustion chambers of the engine, and according to which a signal delivered by an oxygen probe is analyzed, the method a) deducing from the signal, a change in a effective injection time making it possible to regulate richness of exhaust gases leaving the engine; b) calculating CRITERION=?(CRITERION 1+CRITERION2+CRITERION3); c) comparing CRITERION against predetermined minimum and maximum threshold values THRESHOLD_MIN and THRESHOLD_MAX; d) diagnosing a defective condition when CRITERION is outside of a window included between THRESHOLD_MIN and THRESHOLD_MAX.

Abstract: A method for diagnosing a condition of a system for supplying fuel to a fuel injected controlled-ignition internal combustion engine, of a type including an electric control device that makes use of an oxygen probe for closed-loop regulation of a value of an air/fuel ratio admitted to the combustion chambers of the engine, and according to which a signal delivered by the oxygen probe is analyzed, the method a) deducing from the signal a change in injection time correction factor ALPHACL_MEAN making it possible to regulate richness of exhaust gases leaving the engine; b) comparing ALPHACL_MEAN against predetermined minimum and maximum threshold values THRESHOLD_MIN and THRESHOLD_MAX; c) diagnosing a defective condition when ALPHACL_MEAN is outside of a window included between THRESHOLD_MIN and THRESHOLD_MAX.

Abstract: A method for diagnosing a condition of a system for supplying fuel to a fuel injected controlled-ignition internal combustion engine, of a type including an electric control device that makes use of an oxygen probe for closed-loop regulation of a value of air/fuel ratio admitted to combustion chambers of the engine, and according to which a signal delivered by an oxygen probe is analyzed, the method a) deducing from the signal, a change in a effective injection time making it possible to regulate richness of exhaust gases leaving the engine; b) calculating CRITERION=?(CRITERION 1+CRITERION2+CRITERION3); c) comparing CRITERION against predetermined minimum and maximum threshold values THRESHOLD_MIN and THRESHOLD_MAX; d) diagnosing a defective condition when CRITERION is outside of a window included between THRESHOLD_MIN and THRESHOLD_MAX.