CB1100 Idle speed instability problem

[PowerDubs_imp]

Well sounds like you already talked yourself out of trying- but there are plenty of places you can buy an updated ECU from online and return it if the problem still occurs.

[whizzle_dizzler_imp]

Well sounds like you already talked yourself out of trying- but there are plenty of places you can buy an updated ECU from online and return it if the problem still occurs.

Well if that's the case where I can return it, where should I get it from? High dollar electronic parts like that are usually non-refundable

[Cormanus]

Is Nachodaddy the first owner of a 2013 to report this problem?

[Nachodaddy]

Max, I am confused.
You said " i then put another two 470 ohm resistors in parallel with the first pair and the e.c.u. was happy with the 470:2= 235 ohm load per winding of the iacv and the c.e.l. did not light..... i think it is worth connecting two 100 microfarad capacitors across the two windings, this may store/release enough energy to motivate the iacv by making the pulse last longer."
_______________________________________

Are you replacing the IACV with the resistors/capacitors?
Do you remove the IACV?
If the IACV is not removed, how do you connect the capacitors across the two windings?
Thanks for all the work/brainpower you have already committed to this and please forgive my electronic incapacity.

[max]

Cheers Nacho, these are two different idea's;

Idea 1; remove iacv connector ( when the engine has idled normally when switched off so the iacv is in a good position) and insert two 220 ohm resistors as in the picture and leave the iacv disconnected, this will disble the limp mode that you mentioned since the ecu monitors the iacv current and decides it has or has not got a problem and limits the engine to 5000 rpm.

Idea 2; connect two capacitors parallel with the iacv coils, this might hopefully charge ( when the pulse is present ) and release ( when the pulse has stopped ) the capacitor's energy into the iacv ( the pulse appears longer to the iacv ) .

A bit of a trick but i would stick the capacitor's legs right besides the wires to the connector through the " weather pack " which is the silicon rubber seal which stops moisture entering the connector on the wire side.
These seals are generally used by diagnostic techs who insert a test pin or a paper clip beside the wire, the seal will hold the pin in place and the pin will make contact at some point when inserted at the end of travel of the connector, this can also be done with the capacitor leads as a temporary test and go from there.

This second idea is just a theory of me which may or may not work.
The value of the capacitor is arbitrarily ( i just thought this may work ) and you have to observe the polarity of the electrolytic capacitors, again; just an idea.

Good point as i was not clear enough on the second idea, i have not experienced the idle thing personally so i am limited in the things i can suggest, all of this is my best guess and some of it i have verified, like the resistors.

Since it is not always possible for me to know the ability or sense of direction they want to go in of the guys at the other end of the world i just put forward some hints which may work for them and maybe be of assistance to some which are reading the posts, some pick it up some don't that's fine too.

[Nachodaddy]

Thank you Max, I am a great admirer of your work. I understand now. I would try the first approach, but there is a catch. The engine no longer idles at what anyone would consider normal. At start-up, it idles about 1500 and after I ride a few minutes, when I next come to a stop, it is at 2K. I can ride as much as I like after that, as long as I am careful about the idle. So, since the engine has not idled at "normal" before switching off, do you think there is any chance #1 will work? Or will it simply apply 2K as it's new "normal?"

[max]

So if you start the engine and it warms up at 1500 does it not gradually slow down to 1050 or another acceptable level? when sitting still?
Also try disconnecting the engine temperature sensor ( just below the cam chain tensioner at the back of the cylinders ),
with some combination it may decide to come down to 1050 at which point you can shut it down with the ignition key and unplug the iacv.

As you know the butterfy valves of the throttle body are closed at idle, all the iacv does is supply the " correct "
amount of air passed each valve and has an individual adjustment screw ( 4 in total ) under the throttle body to
adjust the airflow to the individual cylinders and is measured with 4 vacuum gauges to make the engine run with an equalized amount of mixture to make it run smooth, i have checked my 4 set screws with 4 vacuum gauges and all was perfect so i left it alone, normally these do not need service unless the idle is rough and thus " out of sync ".

There is no information in the service manual about this, all it says is " don't touch " but if the tech knows what he is doing.........

[Enzofour_imp]

So if you start the engine and it warms up at 1500 does it not gradually slow down to 1050 or another acceptable level? when sitting still?
Also try disconnecting the engine temperature sensor ( just below the cam chain tensioner at the back of the cylinders ),
with some combination it may decide to come down to 1050 at which point you can shut it down with the ignition key and unplug the iacv.

As you know the butterfy valves of the throttle body are closed at idle, all the iacv does is supply the " correct "
amount of air passed each valve and has an individual adjustment screw ( 4 in total ) under the throttle body to
adjust the airflow to the individual cylinders and is measured with 4 vacuum gauges to make the engine run with an equalized amount of mixture to make it run smooth, i have checked my 4 set screws with 4 vacuum gauges and all was perfect so i left it alone, normally these do not need service unless the idle is rough and thus " out of sync ".

There is no information in the service manual about this, all it says is " don't touch " but if the tech knows what he is doing.........

Hi Max, I would like to connect the vacuum gauge, but I don't understand where the 4 connections are, I only see 3, I don't see the connection for the first cylinder on the right. could you indicate it to me, perhaps with a diagram?
Thanks

[max]

So if you start the engine and it warms up at 1500 does it not gradually slow down to 1050 or another acceptable level? when sitting still?
Also try disconnecting the engine temperature sensor ( just below the cam chain tensioner at the back of the cylinders ),
with some combination it may decide to come down to 1050 at which point you can shut it down with the ignition key and unplug the iacv.

As you know the butterfy valves of the throttle body are closed at idle, all the iacv does is supply the " correct "
amount of air passed each valve and has an individual adjustment screw ( 4 in total ) under the throttle body to
adjust the airflow to the individual cylinders and is measured with 4 vacuum gauges to make the engine run with an equalized amount of mixture to make it run smooth, i have checked my 4 set screws with 4 vacuum gauges and all was perfect so i left it alone, normally these do not need service unless the idle is rough and thus " out of sync ".

There is no information in the service manual about this, all it says is " don't touch " but if the tech knows what he is doing.........

Hi Max, I would like to connect the vacuum gauge, but I don't understand where the 4 connections are, I only see 3, I don't see the connection for the first cylinder on the right. could you indicate it to me, perhaps with a diagram?
Thanks

Hi Max, I would like to connect the vacuum gauge, but I don't understand where the 4 connections are, I only see 3, I don't see the connection for the first cylinder on the right. could you indicate it to me, perhaps with a diagram?
Thanks


Howzat Enzo?

Make sure the gauges are indicating the same reading, i use a 4 way aquarium hose connector, produce a vacuum on 3 gauges and then swap one for the last gauge, that way i know the readings are true.
i also use clamps on the rubber hoses so the gauges don't shake themselves to bits and have gentle movement.

[GoldOxide_imp]

lol - over the years I have formed a perception that every time max is up to the challenge to solve a forum question, some CB1100 will get a quick teardown later that day.

I am curious the day a like question is asked:

" ... max? The main journal counter-masses, what are their weight? ... "

Max: " ... uh, that will take me some time. Let me get back to you after my egg salad sandwich ... "