点火线圈不良引起间歇性断火

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<font size="4">   <span style="font-size:10pt;font-family:宋体">故障现象：一辆上海通用五菱</span><span style="font-size:10pt">LZW6360Ei7</span><span style="font-size:10pt;font-family:宋体">型微型客车，配备电喷发动机。该车出现严重的加速无力、“缺缸”现象，以致无法正常行驶。据车主反映，每次更换火花塞后，车辆能正常行驶</span><span style="font-size:10pt">1000km</span><span style="font-size:10pt;font-family:宋体">左右，然后就出现高速“闯车”现象，而且越来越严重，最后导致车辆不能加速，必须进行维修。</span><span style="font-size:10pt"></span></font> <p><font size="4"><span style="font-size:10pt"><span>    </span></span><span style="font-size:10pt;font-family:宋体">故障分析与排除：针对该车的故障现象，首先起动发动机，观察“检查发动机”警告灯是否点亮，结果发现该指示灯在发动机运转时常亮不灭，说明电控系统存在故障。关闭点火开关，在驾驶员侧右下方找出</span><span style="font-size:10pt">16</span><span style="font-size:10pt;font-family:宋体">针诊断插座，用导线短接</span><span style="font-size:10pt">1</span><span style="font-size:10pt;font-family:宋体">号和</span><span style="font-size:10pt">4</span><span style="font-size:10pt;font-family:宋体">号针孔。打开点火开关，观察仪表板右上角警告灯的闪烁情况，读得故障码为“</span><span style="font-size:10pt">0170<span style="font-family:宋体"><span>”</span></span><span style="font-family:宋体">，说明该车的氧传感器不正常。更换氧传感器及工作不良的</span>2</span><span style="font-size:10pt;font-family:宋体">个火花塞，起动试车，一切正常。清除故障码后，将车交付车主使用。</span><span style="font-size:10pt"></span></font></p><p><font size="4"><span style="font-size:10pt"><span>    </span></span><span style="font-size:10pt;font-family:宋体">第二天，车主又将车开进厂，并称故障现象再次出现。将换下的氧传感器与同型号车上的氧传感器进行替换试验，结果发动机工作正常，说明不是氧传感器的问题。再拆下该车的</span><span style="font-size:10pt">4</span><span style="font-size:10pt;font-family:宋体">个火花塞仔细检查，发现</span><span style="font-size:10pt">1</span><span style="font-size:10pt;font-family:宋体">缸和</span><span style="font-size:10pt">4</span><span style="font-size:10pt;font-family:宋体">缸的火花塞发黑，且电极处有油渍，说明</span><span style="font-size:10pt">l</span><span style="font-size:10pt;font-family:宋体">缸和</span><span style="font-size:10pt">4</span><span style="font-size:10pt;font-family:宋体">缸点火不良，所以造成车辆加速不良。</span><span style="font-size:10pt"></span></font></p><p><font size="4"><span style="font-size:10pt"><span>    </span></span><span style="font-size:10pt;font-family:宋体">该车发动机是无分电器式微机分组点火，由</span><span style="font-size:10pt">2</span><span style="font-size:10pt;font-family:宋体">个连体高压点火线圈分别对</span><span style="font-size:10pt">1-4</span><span style="font-size:10pt;font-family:宋体">缸和</span><span style="font-size:10pt">2-3</span><span style="font-size:10pt;font-family:宋体">缸分两次进行点火。由此看来，很有可能是其中一组点火线圈有故障所致。用万用表电阻档测量点火线圈初级绕组的电阻，结果</span><span style="font-size:10pt">1-4</span><span style="font-size:10pt;font-family:宋体">缸端的电阻值仅为</span><span style="font-size:10pt">0.3</span><span style="font-size:10pt;font-family:宋体">Ω，明显过小，说明该点火线圈有间歇性短路现象，所以造成发动机工作时高压断火。</span><span style="font-size:10pt"></span></font></p><p><font size="4"><span style="font-size:10pt"><span>    </span></span><span style="font-size:10pt;font-family:宋体">更换相同型号的点火线圈及</span><span style="font-size:10pt">1</span><span style="font-size:10pt;font-family:宋体">缸、</span><span style="font-size:10pt">4</span><span style="font-size:10pt;font-family:宋体">缸火花塞，再起动试车，一切正常。车辆行驶</span><span style="font-size:10pt">1000km</span><span style="font-size:10pt;font-family:宋体">后复查，各工况下均无异常，故障彻底排除。</span><span style="font-size:10pt"></span></font></p>