How to Quickly Resolve Multi-Cylinder Misfire?
2 Answers
Solutions for multi-cylinder misfire are as follows: fault diagnosis, component replacement, and false alarm monitoring. Fault Diagnosis: First, identify which cylinder or cylinders are experiencing misfire. Connect a fault diagnostic tool and check for any misfire fault codes in the relevant cylinders while the engine is running. Use the diagnostic tool's dynamic data stream function to monitor the specific misfire conditions of the affected cylinders. If basic effective information cannot be obtained through the diagnostic tool, the "cylinder cut-off method" can be used. This involves manually stopping the operation of a specific cylinder (e.g., temporarily cutting off fuel injection or ignition for that cylinder) while the engine is running. If the engine speed drops significantly or the shaking intensifies after cutting off a cylinder, it indicates that the cylinder is functioning properly. If the engine speed does not drop noticeably or the shaking remains unchanged, it suggests that the cylinder is malfunctioning or not working. Component Replacement: Check if the spark plugs of the misfiring cylinders are functioning normally (proper gap, presence of carbon deposits, or electrical leakage). If the spark plugs are faulty, replacing them can resolve the issue. If the spark plugs are fine, perform a high-voltage spark test on the misfiring cylinders. If the spark is weak or absent, inspect and repair components such as the power supply, high-voltage wires, and ignition coils in the ignition system. Replace any faulty parts based on the inspection results. False Alarm Monitoring: Sometimes, the misfire fault is not real but is caused by issues in the monitoring system, leading to the illumination of the engine fault light. For example, in an engine misfire monitoring system that uses the crankshaft speed fluctuation monitoring method, the "tooth signal learning" function of the diagnostic tool can be used to recalibrate and eliminate false alarms.
I've been driving for 30 years and often encountered multi-cylinder misfires, with the engine shaking like an earthquake. For a quick fix, you can pull over and first check if the check engine light is on. If you have an OBD scanner, plug it in to read the trouble codes. Without tools, manually inspect each cylinder's ignition system: check if the spark plugs are severely fouled or burned, take them out to examine; pull out the ignition coils and swap their positions to test, try moving the coil from the non-working cylinder to another; don't overlook the fuel supply, listen for any abnormal sounds from the fuel injectors. A dirty mass airflow sensor can also cause issues, try cleaning it. Don't spend too much time on it—if simple fixes don't help, call for assistance. Prolonged multi-cylinder misfires can damage the catalytic converter, which is costly and dangerous. Prevention is the best strategy: use good fuel and replace parts timely to save hassle and trouble.
