What are the diagnostic methods for ignition system failures?
2 Answers
Diagnostic methods for ignition system failures: 1. Use a multimeter or test lamp to connect to the positive terminal of the ignition coil; 2. If there is power at the terminal, it indicates the ignition coil is functioning normally; 3. If there is no power, it may be due to poor contact in the ignition switch or a short circuit in the wiring between the ignition switch and the positive terminal of the ignition coil. Automotive ignition systems are mainly divided into traditional ignition systems and electronic ignition systems. Traditional ignition systems include: battery ignition and magneto ignition; electronic ignition systems include: transistor ignition systems, semiconductor ignition systems, and distributorless ignition systems. The traditional ignition system, also known as mechanical ignition, operates by the crankshaft driving the distributor shaft to rotate, causing the ignition coil contacts to open and close, generating high voltage electricity, which is then transmitted through the corresponding channels to the spark plugs, thereby igniting the gas in the combustion chamber. The working principle of the electronic ignition system is to sense the engine's operating state through sensors, adjust the ignition timing based on the knock sensor signal, and control the electronic ignition device to ignite at the optimal time.
When I encounter ignition system failures, I usually troubleshoot step by step. First, I check the spark plugs to see if wear and aging are causing insufficient sparking, as spark plugs are the most prone to issues. If the engine has difficulty starting or runs unevenly, it might be a damaged ignition coil, so I use a multimeter to test whether the voltage is normal. Next, I inspect the high-voltage wires for aging or looseness, as poor contact can interrupt current transmission. There's also the ignition control module—I can scan for trouble codes using a diagnostic tool, and an OBD tool can quickly pinpoint the problem. Finally, don’t forget to check the battery and alternator voltage, as unstable voltage can also trigger ignition issues. In my experience repairing cars, I’ve found that regular maintenance, such as replacing spark plugs every 30,000 kilometers, can prevent most problems. If any abnormalities are detected, address them immediately—don’t wait until the engine stalls on the road.
