My car won't start in humid weather.

Dear Car Talk

Dear Car Talk | Jan 01, 1998

Dear Tom and Ray:

I own a 1991 Toyota Camry that has never been any trouble until lately.
Whenever the weather becomes humid, the car won't start. I first noticed
the problem several months ago when I was driving and the car actually
died. My impression was that if I stepped on the gas harder, it died
more quickly. Eventually, the car wouldn't start at all in the humid
weather. The engine would crank, but it wouldn't start. In the past
year, I've had a new timing belt, new spark plugs and new wires. The
part about the humid air is the perplexing part. Any ideas? -- Jason

TOM: I suppose you've already ruled out relocating to the desert
Southwest, Jason.

RAY: Actually, it sounds like a classic case of a bad coil. The coil is
what generates the spark. And when it fails, the spark would be
interrupted and the car would hesitate and die.

TOM: And as we all remember from our high school physics, water conducts
electricity. So moisture (a k a water) in the air is likely to "steal"
some of the electricity that would normally go to the spark plugs. And
that's why it's worse when it's wet out. Eventually, it'll get so bad
that you won't be able to start it, even on dry, sunny days.

RAY: The best solution is to replace the whole distributor, which
includes the coil, igniter, cap, pickup, rotor and plug wires. It's
expensive (around $500 with labor), but, as you say, this car has never
been any trouble. So just consider yourself due. Good luck, Jason.

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