05-09-2020, 06:34 AM
(05-09-2020, 03:55 AM)max_imp Wrote: Pawel thanks for the video, it demonstrates things we have never seen before and is very helpful.
There is some abnormal behaviour with the iacv connected outside the engine,
because the engine is cold at startup the ecu controls the iacv to;
1 retract enough to know it's at the end of the stroke, after that it knows where the iacv is.
2 the ecu then extends about half that amount of steps which is programmed to get the engine to idle at 1500 rpm.
3 the ecu then tries to maintain 1500 rpm by trimming the iacv in or out depending, it chases a set point.
4 as the engine warms up it reduces the rpm's to a programmed " map " of target rpm's until it reaches 1050 rpm.
Like Speed i was expecting the iacv to retract on opening the throttle rather than close it, maybe they programmed it so the throttle is less snatchy or makes the mixture richer, who knows.
But thanks to your video's we now know a lot more about the iacv behaviour, all we have to do is understand it's role in the throttle body.
Pawel if possible at some stage could you do the same thing but with an indicator on the shaft like the copper wire?
Also looking at it sideways makes it difficult to see which way it is moving, something like a piece of electrical tape like a flag would do it with a 45 degree view of it.
Two things i noticed;
1 the pin in Speed's picture seems to protrude ( stick out ) more than seems necessary to guide the piston and;
2 Pawel's piston appears to have a wear mark inside the groove on the bottom at the iacv end.
This is probably not important since the fault went away by replacing the iacv but it just struck me as a bit suspicious.
From what i understand the software inside the ecu was changed in 2014, does this have to do with it and; why is it only happening to a few bikes?
Here is a video clip from "zam's channel" (dl2zam for us hams) in Germany where he removes the iacv housing from a similar throttle body like ours that may help to understand what's going on inside our engines;
https://www.youtube.com/watch?v=_asKPXxu...e=youtu.be
His video's are usually an hour or so long so i picked out what could be helpful for us and no, there is no access from the top, the fuel injection is in the way, i tried.
Followed a lot of his very interesting but technical video's.
No problem MAX. Tomorrow morning the engine will be cold again.
I will repeat the test .. and will do a better video.
I would like to correct that what I felt touching the piston .. I said that it was gently stepping back.
When I put the copper wire on the shaft, you could see that it really was 2 moves. First to the right and second to the left.
In fact, the piston shifted forward and backward alternately.
Maybe a defective IACV series was produced and that series was used our in hondas 2014.
Maybe we should compare the VIN of everyone who has this problem.
Maybe we should compare the IACV series NR which is printed on the valve body.
Mine old IACV 31128A
Speed,s old 31012E
Did it also happen in 2015 and 2016?
My mechanic admitted, however, that there is some ECU re-flash procedure.
He said that this is done by unauthorized workshops ... e.g. to remove the speed limit.
I planned to go to Norway this summer through Denmark. There is a virus age now ... but ... if they open borders, I probably will.
Along the way there is the Honda service, which did the upgrade of Wisedum's bike.
In this situation, I would go there and ask to change the software version.
I can also go to the Honda Poland office (not dealers) which is near my working place.
Maybe I can talk to someone form Honda who will get the copy of new image and will forward it to Polish dealers.
I think that... much has been done in this case.
I don't know how many people have this problem right now.
I had a problem for a year ... I read this post and did nothing about it.
Finally, I decided to take the risk that the IACV replacement would change nothing.
Now I have driven 922km since the IACV exchange.
I fell in love with my again
Speed .... were you able to drive more kilometers after the IACV exchange?