Quote:
Originally Posted by SovXietday
It's condensation all over the exhaust, it heats up and evaporates it and there's your smoke.
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^Exactly, you guys could have tried explaining why instead of bitching that it's a stupid question and this thread would have been done in two posts.
Long explanation:
Bascially when you burn gasoline there are two byproducts, carbon dioxide and water (there's other stuff like carbon monoxide and nitrogen oxide which are bad for the environment, but they make up a small percentage of your "waste".) Now, what happens when you put a glass of cold liquid outside on a humid summer day? Condensation. The water vapor in the air is sticking to the glass. So the smoky exhaust you're getting in that same concept, but inverted. The cold glass is your cold exhaust system and the humid air is your exhaust. So the humid exhaust that isn't really hot yet (cause your engine is cold) is hitting the cold exhaust walls and turning into water, but the exhaust keeps coming and adds energy to the water, turning it into steam, which is what you see coming out of your tailpipe. Once everything heats up the exhaust is so hot that it never condenses on the exhaust walls and just blows right out the car.
Now why does it smell weird. What your smelling is unburnt fuel, remember it, it's a good thing to know. This is caused by the cold start rich condition. Again, this is completely normal. The ECU is running rich when the engine is cold because cold fuel doesn't vaporize well so you don't get a good, complete burn. It has to run rich to keep itself from stalling. Once it reaches operating temperature the cold start condition ends and a normal injector pattern is selected.
Any questions, or clarifications?