Originally posted by SleeperZ:
When the engine is cold (at first start up) the ECU runs the car in an "open loop" mode, which runs the car rich, causing it to heat up to operating temp quicker.
Close, but Wrong. When cold, the engine runs open loop (ie. rich) in order to heat up the catalyst. The catalyst must reach operating temperatre before it can act as a oxygen bank, thus reducing NoX and HC.
96 Sport 2.0L - 190,XXX miles
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