Reasons for Negative Ignition Advance Angle
2 Answers
Engine ignition advance angle is negative due to a faulty knock sensor. If the ignition advance angle remains negative, it indicates that the engine ignition is in a delayed state. Below are specific details about the ignition advance angle: 1. Definition: When an engine (gasoline engine) operates, the ignition timing significantly impacts its performance. Advanced ignition means the spark plug fires before the piston reaches the compression top dead center, igniting the combustible mixture in the combustion chamber. The angle through which the crankshaft rotates from the ignition moment until the piston reaches the compression top dead center is called the ignition advance angle. The ignition advance angle that enables the engine to achieve optimal power, fuel efficiency, and emissions is referred to as the optimal ignition advance angle. 2. Influencing Factors: The most significant factors affecting the ignition advance are engine speed and the combustion speed of the mixture. As engine speed increases, the time to rotate through the same angle decreases, requiring a larger advance angle to achieve the corresponding advance time. The combustion speed of the mixture is related to the mixture's composition, engine structure, and other factors such as combustion chamber shape and compression ratio.
Over the years of repairing cars, I've seen many cases where the ignition timing advance angle turns negative. The main reasons include sensor failures, such as inaccurate signals from the crankshaft position sensor or knock sensor, causing the ECU to misjudge the ignition timing and delay it. There are also mechanical issues, like a loose timing chain or a skipped tooth on the belt, which disrupt engine coordination and push the ignition point back. This can lead to sluggish acceleration, prolonged cold starts, and a noticeable increase in fuel consumption. During diagnosis, I usually start by using an OBD tool to read fault codes and check sensor data streams. If everything seems fine, I then inspect the timing marks. I’d like to remind fellow car owners not to ignore this issue—get it fixed promptly. Otherwise, driving with it could risk a breakdown, especially before long trips. Pay extra attention to engine responsiveness to avoid unnecessary worries.
