一、选用。火花塞选用是否正确，对发动机工作很有影响。根据JB2490—78部颁标准规定，国产火花塞型号由五部分组成。以桑塔纳轿车使用的火花塞“T4196J”为例：首位字母代表类型，“T”表示突出型，无字母代表标准型；“4”表示螺纹尺寸为M14Χ1.25，六方对边距离为19毫米；“ First, the choice. Spark plug selection is correct, the engine work is very influential. According to JB2490-78 ministerial standards, the domestic spark plug model consists of five parts. For example, the spark plug “T4196J” used in the Santana sedan: the first letter represents the type, the “T” indicates the protruding type, and the letters represent the standard type; “4” means the thread size is M14Χ1.25 and the distance between the six parties to the edge is 19 mm;