04-29-2020, 05:27 AM
(04-29-2020, 04:58 AM)max_imp Wrote: Who else thinks it's an alignment problem, thanks Pavel.
Imagine looking at the iacv from the back;
During the time when the rev's are low, can you blip the throttle and move the iacv 1 "nose up", " nose down" left or right?
If it rights itself during one of these movements that would indicate a misalignment with the cylinder, there are two "o rings" holding the iacv in place, they may have enough flexibility to move just enough to clear the dragging spot.
Next thing is to maintain the new position of the iacv somehow.
Interesting observation Pavel.
Not our bike but here is what the iacv cylinder looks like, notice the pin inside the cylinder which runs in the groove of the piston which prevents the piston to rotate;
What if the bracket on the back of the iacv is slightly off measurement or positioned a bit in one direction?
It seems the piston gets "stuck" when it is extended furthest into the cylinder and restricts the idle air flow the most.
Speed the wiring does not change polarity in a reverse rotation but the micro controller decides to reverse the 90 degree timing step and flips 180 degrees, exactly like when you walk backwards and change the timing of your feet, one behind the other instead of in front, same thing
Max
Concern for IACV piston binding was expressed in posts
846
833
775, as excerpted below:
(03-21-2018 07:25 AM)pdedse Wrote:
With this information does Dave now have "probable cause" that the IACV is the culprit?
Dave ordered a new IACV from his Honda dealer.
The part is backordered, so there may be a delay in receiving the part.
Dave emailed that he is loyal to his dealer and choose to not order on-line and his dealer gave him a price as good as/close to on-line.
A couple weeks ago (post 726) I commented: "Even though the IACV operation is a prime suspect in most of the reported idle issues, there may be (instead of or in addition to) poor electrical connection(s)."
This may have been Max's direction earlier than that, but Max wanted to be sure that all other possibilities were checked, since replacing the IACV will take more labor than the other checks.
The only other step which may be practical to do, waiting for the new part, would be to unbolt the IACV (air box in place), pull it back enough to squirt some silicone lubricant into the area, which may facilitate easier movement (or not?)...the theory being that if it is binding, the IACV may not in itself be defective, but not able to operate properly.