Stock ecu closed / open loop behavior

K-Series Programmable ECU installation questions / support issues
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Razathorn
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Location: Lenexa, Kansas, USA

Stock ecu closed / open loop behavior

Post by Razathorn »

I was browsing around and decided to re-read http://www.hondata.com/techk20boostprimer.html , and something stuck out at me...
Closed loop operation.

With the introduction of a wideband oxygen sensor for the K series the stock ECU can and does run closed loop at full throttle. While 14.7:1 is ok for a naturally aspirated vehicle it is far too lean for a boosted vehicle and will cause hesitation. Typically this hesitation occurs while rolling onto the throttle from a cruise and for several seconds after a gear change. Hondata eliminates this by switching to open loop based on manifold pressure.
Huh? I thought the thing read from static tables at wide open throttle / heavy acceleration. Does the stock ecu actually try to use closed loop to make the car hit 14.7:1 at N/A WOT? This seems to not be the case on dyno a/f readings at least.

Wayne
2003 black RSX type-s / jrsc @ 12psi / methanol injection / aftercooled
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Hondata
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Post by Hondata »

The behaviour of the stock ECU is not always logical. It runs closed loop for several seconds at WOT.
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