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Old 01-10-2006, 08:13 AM   #11
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Join Date: Jun 2005
Location: USA!!
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The manual says not to allow it to sit idling. It is actually dangerous to let the car sit and idle. The problem is the O2 sensors do not do anything until they are warm, ie. no adjustments at all. When the car idles cold, it has a tendancy to not burn off all of the fuel in the chamber. Since the O2 sensors are not adjusting the mixture to keep from having extra fuel, the unburned fuel rolls down the exhaust to the cats. Voila...CAT FIRE

The chances of cat fire increase the longer you let it idle since more excess fuel collects down the exhaust. If you start driving, the excess fuel is burned off because the engine is running faster. If you have to warm it up before driving, sit in it and keep the rpm up at about 2000-2500 so it burns fuel more efficiently and has no runoff into the exhaust.

Personally, I start it and go. I try to stay under 3K rpm until it reaches operating temp, then stomp it. The reason for warm up is to get the oil to operating temp so it will flow freely through the entire engine. Keeping it at lower rpms until reaching operating temp accomplishes this without the risk of a cat fire.
1987 928S4 Silver Metallic (980)/Navy (TP) 5-Speed
2000 Boxster Speed Yellow/Black 5-Speed
1966 Wife White/Brown Top
1986 Daughter White/Brown Top (Sold!)
1992 Daughter White/Blonde Top
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