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Old 06-30-2009, 09:32 PM
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Tomguy Tomguy is offline
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Quote:
Originally Posted by WANT '71 280SEL View Post
So there is a huge vacuum leak, but would this cause the car to idle really high and run rich?
Yes. The MAP sensor richens the mixture when it determines the need. The need is based off of manifold vacuum. Idle and just cruising, vacuum in the manifold is high, so it will not give the engine much gas. When you put your foot in it, it opens the throttle body and the manifold vacuum is reduced substantially, the MAP determines the engine is getting more air, so it dumps in more fuel.

Your throttle position switch is misaligned too, your car should be "Hunting" - high idle, low idle, high idle, low idle. Your idle circuit isn't being detected so your engine is in "Runaway idle".

If covering the throttle body completely did not kill the engine, you have bad vacuum leaks. If covering it completely barely slowed your runaway idle, don't run the engine like that. It's WAY too rich, and your oil is probably the viscosity of boiling water due to gas contamination. Fix the leaks and change your oil.
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