CB1100 Idle speed instability problem

[max]

Sync, it runs on 12 v just like Speed mentioned, with a resistance of 105 ohms that means the current is 0,12 Amps or 1.5 wattts per step, not very strong.

There are 2 sets of coils inside and a multi pole permanent magnet on the rotor;



As the pulses are sent from the e.c.u. the motor "steps" with every pulse to it's next position;



You can apply some dc from your supply but the iacv will only move a small amount in one direction, energizing the other coil will move it some more, very un-interesting and disappointing to look at but it will show you the principle.

Normally the current in the two sets of coils is reversed as well but i think if you just take the 12v supply wires and pulse coil A then coil B etc. that will motivate the rotor in one direction ( video? ) and there is no danger in changing polarity in the coils,, they just move in the opposite direction.

In order to not damage the iacv use very short times to energize the coils, if the dc is applied for a long time they will overheat i think, it's very thin wire.

One possible explanation could be that the permanent magnets inside the iacv loose strength over time due to the heat which is a known phenomenon with magnets and would explain why it occurs in slow traffic with heat building up in the throttle body, just a guess and probably not the cause, it could be that the software change produces better pulses with full pulse with other than just a smaller peak as shown in Lord Popgun's nice video.

Thanks for your video, it answers a lot of questions i had previously but it still does not solve the mystery why it fails, although i found the marks inside the groove interesting, awesome of you to post this!

[Lord Popgun]

Max, that is a great visual and explanation on stepper motor operation!

I have about given up on getting the 5 minute file to Speed. So I am going to sign up with YouTube and post it there. I had slow internet problems and got new hi-speed internet service so can actually transfer large files now. Going to work on that tonight. I haven't given up, just had to get the new service going.

[the Ferret]

you guys are like magicians to me. You show it,and explain it, but it just doesn't make it seem real lol

[max]

Ferret we all have our things we get better at, some are good at planting trees, if i planted a tree it would be upside down, trial and error, unfortunately a generous amount of error for me but over time i have picked up some clues that were useful to me and the people that i worked for so i bungled my way through life and here we are, posting gif's on the internet.......

[syncronizator_imp]

Sync, it runs on 12 v just like Speed mentioned, with a resistance of 105 ohms that means the current is 0,12 Amps or 1.5 wattts per step, not very strong.

There are 2 sets of coils inside and a multi pole permanent magnet on the rotor;



As the pulses are sent from the e.c.u. the motor "steps" with every pulse to it's next position;



You can apply some dc from your supply but the iacv will only move a small amount in one direction, energizing the other coil will move it some more, very un-interesting and disappointing to look at but it will show you the principle.

Normally the current in the two sets of coils is reversed as well but i think if you just take the 12v supply wires and pulse coil A then coil B etc. that will motivate the rotor in one direction ( video? ) and there is no danger in changing polarity in the coils,, they just move in the opposite direction.

In order to not damage the iacv use very short times to energize the coils, if the dc is applied for a long time they will overheat i think, it's very thin wire.

One possible explanation could be that the permanent magnets inside the iacv loose strength over time due to the heat which is a known phenomenon with magnets and would explain why it occurs in slow traffic with heat building up in the throttle body, just a guess and probably not the cause, it could be that the software change produces better pulses with full pulse with other than just a smaller peak as shown in Lord Popgun's nice video.

Thanks for your video, it answers a lot of questions i had previously but it still does not solve the mystery why it fails, although i found the marks inside the groove interesting, awesome of you to post this!

My conclusion:
Assuming that the ECU supplies voltage at a correct time , I wonder if IACV responds to all coil feeds and moves the piston as it should be.
Perhaps when the IACV is hot, it is not able to move the piston, and the result is that the engine RPM drops to 500 or increases to 1500.
At what step is the IACV piston then?
I forgot to mention that I did one test before IACV replacement.
Because fuel pomp is very loud i disconnected it (easy to do).
Then I turned on the ignition and listened to whether IACV works or no, (performs adaptation).
Mine was heard very clearly.


I think I will connect the IACV to the motorcycle first before testing with the power supply.
If I damage the IACV, there will be nothing to test cooperation with the motorcycle ECU.

Pawel.

[max]

Pawel since none of our bikes have this issue we have to imagine what occurs, when this problem happens and so your input is enlightening and very importand to me.

Just so you get this in perspective; the images i posted are to explain the principle as easy as i could put it so you understand what it takes to make the rotor move.
The real world is a bit more complex and looks more like the next photo but makes it harder to understand what is happening but this shot shows the pairs of coils with different colors of the windings to show which set is positioned where;



So there's a yet unknown set of coils inside your iacv that moves the rotor in a as yet unknown part of the rotation, the more sets of coils the stronger the attraction but less movement with each step.
And a set can be two, four, six or anymore even number of opposite coils.
The impression i get is that on startup the iacv opens the valve to the end ( so the ecm knows where it is ) with many steps and then closes the valve with a pre-determined amount ( 36 ) of steps

And apologies to anyone who is not so interested in these details on this great forum.

[syncronizator_imp]

MAX,
We will see how IACV works on Saturday.
I'm getting more and more curious.

Backing to :

"One possible explanation could be that the permanent magnets inside the iacv loose strength over time due to the heat"

I wonder why, therefore, a quick reload IACV which is done by turning the ignition key off and on again restores immediately proper engine speed for some time.
Since the engine and the IACV itself does not have enough time to lose high temperature.
Therefore, the magnetic properties of the IACV rotor do not change because the temperature has not changed.

I am already tired today.
I am going to sleep because I have to get up early for work tomorrow.
The good news is that tomorrow morning I will ride a motorcycle again.

Good night to all

[Houtman_imp]

If only I was smarter....

[Speed_imp]

My old IACV phisical condition:

https://youtu.be/0HCgrUdMVIQ

---------------------------------

Speed ​​,
I want to test IACV by connecting it to the power supply.
I want to see if it turns with the same power to the right as to the left.
I don't want to damage the IACV by wrong connection to 12v power supply.
There are 4 connectors.

According to SM one coil - two inside connectors
second coil - to outside connectors


Question:
If I connect the IACV in the wrong (reverse) polarity can I damage the IACV coil ?

No, actually each coil is receiving first 12 volts from one side and then from the other side alternatively as shown in the shots I took, that is why measuring both ends you can see alternative pulses 12V and -12V

Sync, it runs on 12 v just like Speed mentioned, with a resistance of 105 ohms that means the current is 0,12 Amps or 1.5 wattts per step, not very strong.

There are 2 sets of coils inside and a multi pole permanent magnet on the rotor;



As the pulses are sent from the e.c.u. the motor "steps" with every pulse to it's next position;



You can apply some dc from your supply but the iacv will only move a small amount in one direction, energizing the other coil will move it some more, very un-interesting and disappointing to look at but it will show you the principle.

Normally the current in the two sets of coils is reversed as well but i think if you just take the 12v supply wires and pulse coil A then coil B etc. that will motivate the rotor in one direction ( video? ) and there is no danger in changing polarity in the coils,, they just move in the opposite direction.

In order to not damage the iacv use very short times to energize the coils, if the dc is applied for a long time they will overheat i think, it's very thin wire.

One possible explanation could be that the permanent magnets inside the iacv loose strength over time due to the heat which is a known phenomenon with magnets and would explain why it occurs in slow traffic with heat building up in the throttle body, just a guess and probably not the cause, it could be that the software change produces better pulses with full pulse with other than just a smaller peak as shown in Lord Popgun's nice video.

Thanks for your video, it answers a lot of questions i had previously but it still does not solve the mystery why it fails, although i found the marks inside the groove interesting, awesome of you to post this!

That's it Max, what a great graphical explanation! The way it moves to one or the other direction is inverting B and B' for example, in a similar way you change the direction of a triphasic induction motor. I think we are at this point very close to reveal what is the exact issue. I am also sorry it is getting too deep diving technical but I am very interested as it is happening in my own bike. I owe her the time spent and of course I am having so much fun actually!

[Lord Popgun]

If I did it right the 5 minute video is on YouTube now.

Shows IACV pulses from a dead cold start to warm and idling at 1100 at 4:30 time and then a few revs of the throttle.

https://youtu.be/sbKZ-kbjLvQ