Why does the car run rich during warm up? How is that hotter?

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Mar 31, 2004 | 09:54 PM

sporkcrx

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From: broke in the bay area, CA

Why does the car run rich during warm up? How is that hotter?

When cars are started cold, it runs rich to warm up faster than if it's running near stoich. How the hell does this warm the engine up faster? It seems like the closer to to lean it is the hotter it would be running?

Mar 31, 2004 | 10:09 PM

blueeg

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From: bay area, ca, sf

Re: Why does the car run rich during warm up? How is that hotter? (sporkcrx)

more fuel is going into the engine which makes it easier to start especially in the cold mornings. more fuel means your engine is working faster thus creating more heat.

Apr 1, 2004 | 05:06 AM

JimBlake

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Re: Why does the car run rich during warm up? How is that hotter? (blueeg)

You need stoichiometric mixture to burn OK, but any liquid that doesn't evaporate doesn't count. So for example when the engine's cold maybe only 80% of the fuel actually evaporates. So you inject 25% extra, in order to get the PROPER amount that's actually evaporated.

Apr 1, 2004 | 07:50 AM

Chiovnidca

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From: Cincinnati,, Oh

Re: Why does the car run rich during warm up? How is that hotter? (sporkcrx)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by sporkcrx »</TD></TR><TR><TD CLASS="quote">When cars are started cold, it runs rich to warm up faster than if it's running near stoich. How the hell does this warm the engine up faster? It seems like the closer to to lean it is the hotter it would be running?</TD></TR></TABLE>
A cold engine is richened up so it runs better. It doesn't have anything to do with warming it up faster.