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Old 01-05-2010, 03:07 PM   #3 (permalink)
Bow
Old School Hashiriya
 
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Join Date: Dec 2009
Location: Yuma, AZ
Posts: 87

Fred - '98 Nissan Frontier XE
90 day: 26.57 mpg (US)
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Thanked 6 Times in 3 Posts
I know in the Nissan ECU programing, the Open Loop/Close Loop on start up is determined but the coolant temp.

For Example, my '91 240SX and my '98 Frontier (both use the same KA24DE DOHC four cylinder engine), when cold started it runs as a simultaneous multiport injection system, where every injector fired two times for each engine cycle, then with the cool temp reaches operating temp, it switches to sequential multi-port injection.

Your Saturn may be similar in its operation, which would describe why the Open loop/Closed loop switches about the same time with the different O2 sensors.

Just a thought
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