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Old 01-23-2009, 11:31 AM   #1 (permalink)
RobertSmalls
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Join Date: Aug 2008
Location: Buffalo, NY, USA
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Prius C - '12 Toyota Prius C
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My car is too eager to switch to open loop

I've had my scangauge for a few weeks now, and I've noticed a few undesirable things my engine management computer does, especially when it's cold.

Most annoying is the very high idle until it warms up. I show an open loop idle, 1500 rpm, and 1gph for the first minute or two of driving. Once it gets vaguely warm, I see open loop, 1000 rpm, 0.50gph. This is still not as desirable as the closed loop, 500rpm, 0.25gph that I've come to expect. I often see the 0.50gph idle with the coolant temp at 195F while I'm trying to pulse and glide. I run 0W30, so I'm confident it can idle lower especially while it's cold. Can I force it into closed loop idle?

There's a seperate issue: whenever I open my throttle more than, say, 1/3, it goes into open loop. Yeah, I know, welcome to the real world. Still, can I keep closed loop for slightly larger throttle aperatures? What if I mod the TPS?

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