Jim Grant's Tech Tips

85 Nissan Sentra, Ignition Problems
Q: I had bought an ‘85 Nissan Sentra (second car). It rode and handled well except that sometimes it would stall and not start for quite a period of time.
It was said that it was vapor locked but no one could correct it. I sold it and bought an ‘84 (good shape) and I’ll be darned, it does the same thing. A friend recently told me that it could be a weak coil. What’s your guess?

A: Your friend could be right. I would also suggest close inspection of the power transistor, which is mounted next to the ignition coil. The power transistor is a computer controlled switch for the ignition coil that is prone to corrosion problems and can fail when hot. One way to prove whether or not the ignition is the problem is to prove if there is ignition spark or not when the engine quits. Pick yourself up a spark tester; they’re not much money. The next time the vehicle quits install the spark tester on the coil wire and try to start the engine. If there is no spark at the coil wire then the ignition coil or power transistor is in question. If the spark is good and strong then there are other problems.