Quote:
Originally Posted by Tcoat
The high idle, rich mixture, cold start process has existed since about the Model A. It just used to be done with a choke instead of a computer. Cold start high idle is about more than just heating up the cats. It is also about building oil pressure and reaching proper operating temperature more efficiently.
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I forgot about the choke, I took a motorcycle class once and they had us use this to start the bike.
people also forget that high idle used to be via coolant temp sensor/ECU control + IACV which usually had a bimetal element that caused intake air to be bypassed, thus resulting in a cold start high idle. modern engines don't have quite the same system anymore.
and yes, warming up the engine was critical. not everyone has the luxury of slowly driving your car to reach operating temps ...