风华正茂

过程是这样的：
早晨从幼儿园回来的时候，车发动机在停牌或等红灯的时候，明显的感觉乏力，转数好像也下降很多，然后就熄火了，再次打火后，行走也有气无力，勉强找到泊位停靠。
我以为油箱只剩半小格油，是油不足的问题，晚上加了大半箱油后，问题依旧，甚至更为严重。发动一切正常，有时几秒钟后就熄火，连挂档都来不及。其中挂倒档时，倒车也没劲，必须踩油门稍微加点劲才行。
请教，这是什么问题，是分电器、电池还是发电机的问题，抑或其他问题。
车是93年Nissan Altima，老爷车了。

QQ8*8

我是新手，我感觉先把电瓶接头处理一下，重新接好试一试在看。

风华正茂

谢谢这位朋友的意见。

今天下午我曾翻阅了很多以前朋友对于车各种问题的帖子，曾有人提到过密码锁工作不正常也会出现类似的现象——经常熄火。当然更多的是诸如电瓶、分电器、发电机方面的问题。
晚上，我再次尝试开车在周围转转，结果一切都正常了，还约了朋友出去买点东西，当然也是为了试试车到底怎么样。这是我才注意到，平时显绿灯的密码锁（因为是冬天，我取消了密码输入，直接打火就行了），不知怎么回事又恢复了初始设置，变成闪红灯了。

看来是密码锁工作暂时失灵造成的上述问题。供遇到类似问题的朋友借鉴。

WangYcca

Post by 风华正茂
过程是这样的：
早晨从幼儿园回来的时候，车发动机在停牌或等红灯的时候，明显的感觉乏力，转数好像也下降很多，然后就熄火了，再次打火后，行走也有气无力，勉强找到泊位停靠。
我以为油箱只剩半小格油，是油不足的问题，晚上加了大半箱油后，问题依旧，甚至更为严重。发动一切正常，有时几秒钟后就熄火，连挂档都来不及。其中挂倒档时，倒车也没劲，必须踩油门稍微加点劲才行。
请教，这是什么问题，是分电器、电池还是发电机的问题，抑或其他问题。
车是93年Nissan Altima，老爷车了。

换PCV valve，就几块钱一个，正常来说5万公里要换。如果PCV valve老化，成压力不够，会造成发动机转速过低或抖动，严重的会熄火。

Harris

大哥：

啥 叫pcv alue? 在哪？啥 用图？

WangYcca

The PCV valve connects the crankcase to the intake manifold from a location more-or-less opposite the breather connection. Typical locations include the opposite valve cover that the breather tube connects to on a V engine. A typical location is the valve cover(s), although some engines place the valve in locations far from the valve cover. The valve is simple, but actually performs a complicated control function. An internal restrictor (generally a cone or ball) is held in "normal" (engine off, zero vacuum) position with a light spring, exposing the full size of the PCV opening to the intake manifold. With the engine running, the tapered end of the cone is drawn towards the opening in the PCV valve, restricting the opening proportionate to the level of engine vacuum vs. spring tension. At idle, the intake manifold vacuum is near maximum. It is at this time the least amount of blow by is actually occurring, so the PCV valve provides the largest amount of (but not complete) restriction. As engine load increases, vacuum on the valve decreases proportionally and blow by increases proportionally. Sensing a lower level of vacuum, the spring returns the cone to the "open" position to allow more air flow. At full throttle, there is nearly zero vacuum. At this point the PCV valve is nearly useless, and most combustion gases escape via the "breather tube" where they are then drawn in to the engine's intake manifold anyway.