Tim D Posted June 30, 2023 Report Share Posted June 30, 2023 Hi all, I've been trying to fine tune a weird problem with idle control on my Subaru Impreza STI (EJ257) and noticed that the vehicle speed (LF Wheel Speed) as seen by the ECU doesn't return to 0 mph very nicely. It sort of hangs around 4-6 mph, then drops to 0 mph at the last minute, usually after coming to a standstill. I think this is detrimental to the transition to idle control. I looked at datalogs from 4+ years ago and these also show similar effects when coming to a standstill, so I am wondering how precise the indicated speed should be? I've attached a screenshot of a datalog showing this behaviour (I came to a standstill very smoothly, not as depicted in log): Happy to post logs etc, but wanted to know how good it should be, I'm assuming what I am seeing is sub standard? Any info/tips would be greatly appreciated. Quote Link to comment Share on other sites More sharing options...
Adamw Posted June 30, 2023 Report Share Posted June 30, 2023 Thats likely as low as it can read. The "hang" is the ecu waiting for the next tooth to arrive, if it doesnt arrive within the timeout period it will set the speed to zero. Set the idle lockout somewhere above that should be fine. Quote Link to comment Share on other sites More sharing options...
Tim D Posted July 1, 2023 Author Report Share Posted July 1, 2023 Excellent, thanks for the speedy reply Adam, much appreciated. Quote Link to comment Share on other sites More sharing options...
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