CB1100 Idle speed instability problem

[Lord Popgun]

Doc, you know, we were just joking about the creds back then. Like we tend to do here.

Found the needles, have some jumpers ready and a long one for the proper ground so as to use 2 probes at once.

[SportsterDoc]

Doc, you know, we were just joking about the creds back then. Like we tend to do here.

Found the needles, have some jumpers ready and a long one for the proper ground so as to use 2 probes at once.

I know and we were still getting acquainted...and a couple times I probably overdid the background and appreciate Moderator deletion, at my request. At the risk of perhaps having to again do so, I will share this:

In 1985, I was asked for input on an automation project, for which I sold the DC motor, gear reducer and brake.

The machine, one of many built by Calmation's predecessor, inserted .025 square pins (bandolier fed) into an AT&T backplane at the rate of 20 pins per second: 5 pin head, dual heads, 2 insertions per second.

The challenge was to increase speed, but when motor speed was increased, the brake (sensor activated for positioning) would overheat and cause position drift. A larger brake would dissipate the heat, but created an inertia problem and advancing the timing of sensor activation was inconsistent.

My solution was not at all technical: I simply suggested blowing air on the brake to prevent overheating. It worked...and was not previously discussed in either Warner (electric clutch/brakes) nor Horton (pneumatic clutch/brakes) factory technical seminars.

The moral of this story is to recommend not overthinking a problem or its solution.
Correction
I forgot about DTC 29-1, which is most likely connector or wiring issue, not a positional error.
I would correct post 1042 and 1047 but too much time has elapsed for me to do so.

[Lord Popgun]

Well, first test. One probe on Bl/R and one on Bl/Y. Both probe ground leads connected to battery negative terminal.

Both traces show a square wave pulse train that comes up, then goes away. I am taking video’s and that I can email and someone can post them if they want. I AM NOT a videographer. I’m am using my iPhone on a stand. Due to test setup I can’t really watch the scope and reach the key. So, I start the video, turn on the key and wait for a response.

Interestingly, the pulse train does not appear until the fuel pump is done cycling. This is consistant every time I turn on the ignition. EDIT: not true. on the second run they showed up before the pump was done cycling.

The second run was interesting, but I messed with the scope and kinda messed up the video. So I’ll run it again in a while.

[Speed_imp]

Well, first test. One probe on Bl/R and one on Bl/Y. Both probe ground leads connected to battery negative terminal.

Both traces show a square wave pulse train that comes up, then goes away. I am taking video’s and that I can email and someone can post them if they want. I AM NOT a videographer. I’m am using my iPhone on a stand. Due to test setup I can’t really watch the scope and reach the key. So, I start the video, turn on the key and wait for a response.

Interestingly, the pulse train does not appear until the fuel pump is done cycling. This is consistant every time I turn on the ignition. EDIT: not true. on the second run they showed up before the pump was done cycling.

The second run was interesting, but I messed with the scope and kinda messed up the video. So I’ll run it again in a while.

There are two shocking things I did not expect in my case. The pulse train goes from - 12v to 12v (was expecting from 0v to 12v). On opening throttle from zero the pulse train appears again for less than a second, and this is what I don't understand. I put one end of the probe in Bl/Y and the other in Bl/O, in other words, measuring what the coil is receiving. I believe this pulse train on opening throttle is somehow screwing the position of my valve. If you want you can send the video to jose.maria.miranda.castillo@gmail.com so I can post it here with a youtube link!

[Lord Popgun]

Speed, I sent you a PM.

I want to send you the video. You can see the scope settings too. I used the same you had set. 10v, 25Ms/c (my scope won’t do 20)

I haven’t video’d a bike running yet. Getting ready to though.

[Cormanus]

Doc, you know, we were just joking about the creds back then. Like we tend to do here.

Found the needles, have some jumpers ready and a long one for the proper ground so as to use 2 probes at once.

I know and we were still getting acquainted...and a couple times I probably overdid the background and appreciate Moderator deletion, at my request. At the risk of perhaps having to again do so, I will share this:

In 1985, I was asked for input on an automation project, for which I sold the DC motor, gear reducer and brake.

The machine, one of many built by Calmation's predecessor, inserted .025 square pins (bandolier fed) into an AT&T backplane at the rate of 20 pins per second: 5 pin head, dual heads, 2 insertions per second.

The challenge was to increase speed, but when motor speed was increased, the brake (sensor activated for positioning) would overheat and cause position drift. A larger brake would dissipate the heat, but created an inertia problem and advancing the timing of sensor activation was inconsistent.

My solution was not at all technical: I simply suggested blowing air on the brake to prevent overheating. It worked...and was not previously discussed in either Warner (electric clutch/brakes) nor Horton (pneumatic clutch/brakes) factory technical seminars.

The moral of this story is to recommend not overthinking a problem or its solution.
Correction
I forgot about DTC 29-1, which is most likely connector or wiring issue, not a positional error.
I would correct post 1042 and 1047 but too much time has elapsed for me to do so.

Doc, What do you want the posts to say? Ferret or I will edit them for you.

[SportsterDoc]

Max posted this 17 Dec 2017 in postt 21 of "diagnostic trouble codes and sensor testing" thread:

http://cb1100forum.com/forum/showthread....Diagnostic

"Bonus footage; iacv operation on my bike, as usual a bit vague, the video editing program had trouble at 5% slow motion but what happens is ; on startup the iacv opens 65 steps and then closes 12 steps with a cold engine and 35 wiith a warm engine.

This happens in the blink of an eye as demonstrated at the very end of the video so i slowed it down to count the steps and direction, open and close.

the ecu does not know what position the iacv is at startup , so it always commands the valve open with 65 pulses, it then makes a decision to close x many steps based on the temperature of the eot sensor."

Doc, you know, we were just joking about the creds back then. Like we tend to do here.

Found the needles, have some jumpers ready and a long one for the proper ground so as to use 2 probes at once.

I know and we were still getting acquainted...and a couple times I probably overdid the background and appreciate Moderator deletion, at my request. At the risk of perhaps having to again do so, I will share this:

In 1985, I was asked for input on an automation project, for which I sold the DC motor, gear reducer and brake.

The machine, one of many built by Calmation's predecessor, inserted .025 square pins (bandolier fed) into an AT&T backplane at the rate of 20 pins per second: 5 pin head, dual heads, 2 insertions per second.

The challenge was to increase speed, but when motor speed was increased, the brake (sensor activated for positioning) would overheat and cause position drift. A larger brake would dissipate the heat, but created an inertia problem and advancing the timing of sensor activation was inconsistent.

My solution was not at all technical: I simply suggested blowing air on the brake to prevent overheating. It worked...and was not previously discussed in either Warner (electric clutch/brakes) nor Horton (pneumatic clutch/brakes) factory technical seminars.

The moral of this story is to recommend not overthinking a problem or its solution.
Correction
I forgot about DTC 29-1, which is most likely connector or wiring issue, not a positional error.
I would correct post 1042 and 1047 but too much time has elapsed for me to do so.

Doc, What do you want the posts to say? Ferret or I will edit them for you.

Doc, What do you want the posts to say? Ferret or I will edit them for you.
Thank you.
1042 Pls delete "I am not aware of a DTC for the IACV" there is one, DTC 29-1, but it is not related to position error.

1047 "It has no feedback, unlike a servo motor with an encoder, hence no associated DTC" add "FOR POSITION ERROR"

[Cormanus]

Done, Doc.

[Wisedrum]

Too bad, that a software update isn't allowed to fix the idle problem in the USA. Honda released it due to this problem and it totally cured this very annoying fault unexpensively for me without changing other parts of the bike, which more or less feels like fishing in the dark. The reason for a missfunction is to be seen in a not correct programming for the injection combined with the intake valves, a Honda dealer explained in my country after his treatment. This was that.

Wisedrum

[Speed_imp]

Too bad, that a software update isn't allowed to fix the idle problem in the USA. Honda released it due to this problem and it totally cured this very annoying fault unexpensively for me without changing other parts of the bike, which more or less feels like fishing in the dark. The reason for a missfunction is to be seen in a not correct programming for the injection combined with the intake valves, a Honda dealer explained in my country after his treatment. This was that.

Wisedrum

Good info! And good to try before starting with the work! A programming issue makes sense viewing the signals I am getting to the IACV. I will talk with my Honda dealer in Barcelona just in case they know about it. By the way, could you tell me your Honda dealer's name? Just in cause they are not aware here in Barcelona. Actually a couple of years ago they supposedly reflashed my ECU. Thanks!
In this video

https://youtu.be/aT2bjVxi0qo

Can be seen that a pulse train appears at the moment of opening throttle and after releasing idle speed is low again...
And in this other video the signal to IACV when idle speed is stable, normal operation. When opening throttle the pulse train does not appear...

https://youtu.be/p-wqDjIqz2k

Someone else thinks that my issue is related to the pulse train on opening throttle? This would explain why the issue worsens when in heavy traffic (closing and opening throttle slightly repeteadly)