例四故障现象:一辆北京7250切诺基吉普车,发动机稍有回火现象,于是驾驶员对点火正时进行了调整,调整后发动机反而更加无力,而且燃油消耗增加。故障分析与排除:根据故障现象,我们对点火正时进行重新调整,其具体步骤如下:1)确定一缸压缩行程上止点并对好标记。拆下一缸火花塞,用 Example 4 failure phenomenon: a Beijing 7250 Cherokee jeep, the engine a slight tempering phenomenon, so the driver on the ignition timing has been adjusted, but the engine is adjusted even more powerless, and increased fuel consumption. Fault Analysis and Troubleshooting: According to the fault phenomenon, we re-adjust the ignition timing, the specific steps are as follows: 1) to determine a cylinder compression stroke TDC and a good mark. Remove the cylinder spark plug, use