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My Nissan SX gave me quite a scare I turned...

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Dear Tom and Ray:



My 1988 Nissan 200SX gave me quite a scare. I turned the ignition key and
it sounded like the motor was already running. I sat there for a minute
thinking I had left my car running. No, I had the keys with me. I turned
the key again and it started immediately. This happened again about a week
later to a mechanic when I had my car in the muffler shop. This was three
weeks ago and it hasn't happened since. What could it be? Will this get
worse, quit happening or should I get to a repair shop? -- Lea

TOM: Well, I have good news and bad news, Lea. The good news is that you're
not losing your mind; you had not left your car running when you turned the
key.

RAY: The bad news is that after you hear our diagnosis, you're going to
WISH you had just left the car running.

TOM: You've got a bad ring gear on your flywheel, Lea. When you turn the
key to start the car, a little gear on the starter meshes with a big gear
(the ring gear) on the flywheel. And turning that flywheel is what starts
the engine. The problem is that the gear on your flywheel has some broken
teeth.

RAY: Has it been eating at my mother's house lately?

TOM: When you turn off the engine, and the flywheel happens to stop in just
the wrong place (where the broken teeth are perfectly lined up with the
starter gear), you get that horrible gnashing noise next time you turn the
key. And if you're lucky, that gnashing is enough to move the flywheel a
couple of degrees; just enough so on the next try, the starter hits some
good teeth and the car starts right up.

RAY: But it's going to get slowly worse, Lea. If you don't mind the
inconvenience, you can drive it like this for a while, but as time goes by,
it's going to happen more and more often. And someday it won't start at
all.

TOM: So if you've got $500 or $600 lying around with nothing to do, you
might as well grit your teeth (ha, ha) and get a new flywheel. If not, you
might see if your local bank has a "flywheel club" to help you start
saving. Good luck.
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