Reply To: Inconsistent rpm at idle, stalling + jerky acceleration GT250 EFI 2010
Jo. It has been a year since I was playing with the ISC so my recollection may not be accurate. But here goes.
You cannot screw the piston back in the normal sense since I believe the piston moves in a guide along the axis. This guide is what allows the in/out movement when the stepper motor threaded spindle rotates inside piston’s “nut”.
I think what I did was align the piston to mate with the ISC housing and then hold the piston and body between thumb and forefinger with sufficient pressure to stop thye piston rotating along with the stepper motor.
Turn on the ignition key and initially the stepper motor would be trying to push the piston further out. During the second phase the stepper motor will rotate in the opposite direct and provide you are still aligned the piston will be drawn back in.
At that point turn off the ignition, fit the ISC back into the airbox, then turn the ignition back on. At this point the system should initiate the piston calibration procedure again.
I am still using the same ISC as I concluded it is not the source of the problem I have with my bike. Hope this helps.