The idle of my S3 1050 from 2010 is very 'jumpy' at random times. Doesn't matter if the bike is hot or cold. Sometimes the problem occures right after starting the bike, sometimes it doesn't happen at all.
I got the bike second hand since 2 months and the problem started the second day that I got it. The bike has a 3-1 arrow low boy exhaust with K&N filter and SAI is on.
I've used TuneECU to update the mapping (to #20539), it had an outdated 3-1 mapping on it (#20209) but this didn't fix the problem. Idle is set to I believe 1400 rpm but it is never steady, it always jumps around 1100-1450rpm and at random times when nearing lights or roundabout and pulling the clutch, it drops to 800 and sometimes even stalls.
I've done the TPS and idle test in TuneECU. The TPS is set to 0,63v (0,60v ideal) and increases gradually as it is supposed to on opening the throttle. Once the idle test starts however, the bike starts making it noise (i believe this is the stepper motor) and shows 0,77v (0,75v ideal). But now, the pitch of the noise changes and once this happens the idle voltage drops to 0,60v and up to 0,78 and keeps jumping around. I don't think this is supposed to happen..?
Does anybody have an idea of what the problem could be here? What sensor does the stepper motor use to get it's position from? I will try to use the 'reset adaption' function from TuneECU this afternoon and will update this post after.