The Case of the Faulty Converter

Jul 26, 1996

RAY: This is an automotive Puzzler. A do-it-yourselfer came in and said, "Jeez, guys, I have a problem, and I hope you can solve it. I think I have a faulty part."

And I said, "Oh, yeah? What part?"

I think he had something like an '81 or '82 Chevy pickup. It's not important what he had, but he had a late-model vehicle of some kind.

He said, "Gee, I have a problem where my car has no power. I can't climb hills. One day while trying to climb a long steep hill, I got out and looked under the car and lo and behold my catalytic converter was glowing red. And I said to myself, Jeez, it must be all plugged up. I listen to you guys all the time."

So there he is, out in the middle of nowhere, unable to climb a hill and his converter is glowing red, and what does he do? He goes out and buys a new converter, and spends the whole next weekend busting his knuckles removing the old converter and putting on said new converter.

And guess what?

TOM: He tried to climb the same hill at the same time of day, didn't make it, looked under the car, and lo and behold, Sonja Henie's Tutu! It was red hot again.

RAY: You are clairvoyant.

TOM: No, I'm Tom, Claire is my sister-in-law.

RAY: So he realized that either he misdiagnosed the problem, or, as he suspects, he bought a faulty converter. He returns to the parts store, irate. And the guy says, "Unlikely, twerp. You did not buy a faulty converter."

Whereupon he comes to our garage, head in hand, empty pockets, weeping, "Help me! Help me!"

The question is, what's wrong? Was it really his converter? And why not?


RAY: No, it wasn't the converter. What was wrong was that his timing was off. And the reason that his converter was glowing red was that the combustion of the gas was actually taking place in the first part of the exhaust system. Because the timing was so far off that he wasn't getting combustion in the cylinders, rather he was getting it where? In the exhaust system!

TOM: And what's right up front there?

RAY: The catalytic converter. That's why he also had no power, because the energy of those explosions was going into turning that pipe and that converter cherry red, and not going into pushing the pistons down.

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