The Fuel Injector

Mar 15, 2022

Oh, hey, it's time for the new puzzler. I know you can't wait. I didn't want to get anyone's hopes too high which is why I always say it's a new puzzler coming up. But I didn't say a great puzzler, because you shouldn't raise people's expectations. So this is just a lousy old mediocre puzzle. But it's actually interesting.

A fellow called the garage the other day. This fellow called the shop, and he'd been working on his Jetta out in the driveway. And somebody said to him, some mechanic had said, you have fuel contamination, so you must flush out the entire fuel system. Because you have dirt and water and dead bears and all kinds of stuff in the tank.

So he does it, he drains the tank and he and he decides that he's going to go even further than that. And he removes from the fuel distributor, the tubes that run, they're flexible tubes that run from this thing called the fuel distributor to the injectors. And he takes them all off and he sprays carburetor cleaner into them and gets them all nice and clean. And he goes to put them back.

And that's where the phone call came in. He calls me up and he says, "I did an awful thing. I don't remember where they go."

This is equivalent to swapping the wires and the spark plugs. He's got all these tubes. And he says, "How can I figure out where they go?"

I mean, how many possibilities are out there? Well, you know the four factorial? 24 ways to do it. Is that right? That could be right.

Any one of the four could go in one place. Now my brother argued that since there are only 24 options, he should just try them all!

But I had a different idea. I told him to pick anyone. Wherever the lines reach, just hook them up and drive the car.

"Will it work?" he said, "maybe it won't run." I said, "Don't worry about it. It'll be fine."

The question is will it be fine?



Hey! I'll give you 20 bucks if you can remember last week's puzzler. Nevermind, time's up!

Here's the answer, and it is not, as some have speculated, that I wanted to ruin his engine.

No, the answer is that his car has a fuel injection system called CIS which is Continuous Injection System. And because it has continuous injection, what it does is it's all the injectors spray all of the time instead of having electronic injection which sends a pulse to an individual injector and has it shoot in fuel at the precise time that that intake valve is open.

Whereas continuous injection just sprays the junk just like a carburetor would in fact, a carb is just delivering fuel all the time and if a valve happens to be open it sucks the stuff in and if not, the fuel just sits there. But that's the reason he could put them anywhere.

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