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1979-1993 & 94 Conv [Subscribe to Daily Digest] |
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, Thu, 19 Sep 2002 08:17:30
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The AIC is like a second throttle plate - it is a device to control the amount of air entering the engine. When the real throttle plate is closed off (at idle), it is a near complete seal - so, the engine isn't getting *any* air through it.
Now, the engine does need to get *some* air at idle, so the AIC is an electronic valve that lets some in. The engine control unit can sense engine rpm's, and it opens and closes the AIC to keep the rpm's at a certain number. Thus, the car idles at that given speed.
Back in the old days, there were other (mechanical) means to let a bit of air in when the throttle plate was shut. These weren't the best solutions, because usually they were "dumb" - that is, they let a certain amount of air in, and didn't pay any attention to the results. So, you'd get a variable idle speed, that went up and down as the car got warm or cold or the engine wore out or any of a number of other factors. The AIC on the other hand, being computer controlled, can manage to keep a constant idle speed under a variety of conditions.
If you are getting really sick of your idle problems, and you're a real cheapskate, you could always do this - block off the two hoses going to the AIC, take the throttle plate out of the TB, and drill a really small hole in it. Then, your engine will get a set amount of air when the plate is closed. This is the most simple and inflexible way to get your car to idle, and is in reality a terrible solution for daily driving, but it gets the job done.
In short, as Mr. Black stated, a "dead" AIC can't really strand you or cause any permenant damage. It'll just be more of an inconvenience, since your engine will either want to die (stuck closed) or idle really high (stuck open.)
And one final note - don't unplug the AIC when the car is running. You can damage the ECU.
-Nate
1991 VW Corrado g60, 182k
1988 Saab 900 Turbo, 82k
posted by 12.3.14...
, Thu, 19 Sep 2002 08:17:30, Thu, 19 Sep 2002 09:52:36
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