How many spark plugs should be replaced at once for a sedan?
1 Answers
Replace all of them. Below are the relevant details: 1. Theoretically, even if you replace just one spark plug with the same brand and model, the discharge gap between the new and old spark plugs will differ, as will their resistance values. Not replacing all of them may lead to issues such as engine shaking, difficulty in acceleration, and increased fuel consumption. This is because differences in spark plugs can cause variations in ignition timing and energy, resulting in an imbalance in power among the four cylinders. 2. Spark plugs have a certain lifespan, and products from the same batch should have similar quality and longevity. If one or two spark plugs have issues, it indicates that the others are nearing the end of their lifespan as well. Therefore, replacing them all at once prevents future problems. Currently, the common electrode materials on the market include copper, nickel alloy, platinum, and iridium (platinum and iridium are generally referred to as precious metals). The electrical conductivity of these metals increases from left to right (copper < nickel alloy < platinum < iridium), while the voltage required for ignition decreases from left to right (copper > nickel alloy > platinum > iridium). Thus, precious metal spark plugs place less load on the engine and are beneficial for reducing fuel consumption. Additionally, precious metals have a longer lifespan, though their price increases with performance.
