Grand Prix 125
Join Date: Aug 2010
Location: Laval, Quebec, Canada
Thanks again for posting all the good info. I am learning a lot. I've got an 09 st and been chasing a "low idle speed issue" since almost day 1. In my quest to find the root cause i've found issues (cracked boot between air box & throttle body, loose clamp on throttle body, ect..) that i thought would explain the low idle issue but although not as severe (not stalling anymore) the issue remain. Before putting the bike in the shed for the winter, i plugged tune ECU to verify some stuff;
1) As you stated, the TPS is reading of 0.60V when the stepper is closed to 0.75V when the stepper is fully open.
2) The throttle position reads 0.60V when fully closed and 4,19V when fully open.
3) When the ignition is off, the idle stepper motor's control lever arm is touching the throttle cam. This is contrary to what you are stating...Maybe that could explain my issue. What do you think ?
4) I've also noted that before starting the bike, the coolant temp was showing 3 Deg C while the air intake temp was showing 10 Deg C. The bike was cold soaked since a week and the ambiant temp was indeed around 3 - 4 Deg C. So there was a split of 7 Deg C. I would have expected both temps should be within a 2 -3 deg C. Not sure if 7 Deg is too much. What do you think ?
5) Swapped both press sensors (same PN), issue remain
6) Isolated the coal canistor and its tubing, issue remain.
7) Throttle are balanced, checked.
8) New spark plugs & air filter. Issue remain.
9) MAP sensor tubing checked OK.
10) Tried "ethanol free" gaz, issue remain.
11) Remapped the ECU at the dealer shortly before the winter. Don't know if it will make a difference. We'll see next spring...
I am running out of ideas...Any ideas / hints are more than welcome.