Idle Control Valve clean or replace?

[Alexei9012]

Hey guys got a question,

My m3 has a rough idle when cold then goes away but my rpm aren’t solid and they constantly jump up and down. I’ve already don’t the fuel breather valve so next is the ICV.

I’ve only been able to find info that it needs to be replaced. I watched M539 Restoration and he just cleaned his with throttle cleaner, is this a viable fix or do I need to replace the unit? I have no codes being thrown by the rough idle either.

[Honda]

Originally Posted by Alexei9012

Hey guys got a question,

My m3 has a rough idle when cold then goes away but my rpm aren’t solid and they constantly jump up and down. I’ve already don’t the fuel breather valve so next is the ICV.

I’ve only been able to find info that it needs to be replaced. I watched M539 Restoration and he just cleaned his with throttle cleaner, is this a viable fix or do I need to replace the unit? I have no codes being thrown by the rough idle either.

I am also wondering about this as well. I am not really sure what exactly fails in this device to replace. I do have bad idle from time to time with no CEL.

[Alexei9012]

Originally Posted by Honda

I am also wondering about this as well. I am not really sure what exactly fails in this device to replace. I do have bad idle from time to time with no CEL.

From what ive seen and heard, it seems to get clogged with carbon.

[Honda]

I did do alot of research but I didn't get much info on cleaning ICV. Most people just replace it and I don't get the reason or justify it.

I do understand that it is too much work to get to it but ICV brand new is too expensive.

[Alexei9012]

Originally Posted by Honda

I did do alot of research but I didn't get much info on cleaning ICV. Most people just replace it and I don't get the reason or justify it.

I do understand that it is too much work to get to it but ICV brand new is too expensive.

Yeah i agree, i might try clean it and see how i go, worst comes to worst well know and then can replace it for peace of mind.

[Honda]

Originally Posted by Alexei9012

Yeah i agree, i might try clean it and see how i go, worst comes to worst well know and then can replace it for peace of mind.

Please keep us posted if it gets improved after cleaning

[t_win]

While you're in there might as well do the throttle actuators if you haven't yet.

[yardbro]

A good place to start would be to run the ICV service function within ISTA to test its function and run a diag. I have used it in the past and it should be able to give you some good information. It has been a while, but if I remember correctly it should be able to show you specified parameters and if your unit either passes or fails each part of the test (similar to what we have for testing function of throttle actuators).

These things are getting up there in price nowadays so I would definitely lean towards the side of trying to clean it or be absolutely sure its faulty before throwing money at a new one.

[pathall1]

Originally Posted by Alexei9012

Yeah i agree, i might try clean it and see how i go, worst comes to worst well know and then can replace it for peace of mind.

Did you ever clean this? Curious as to your results. Planning on doing my throttle actuators soon and would like to also address this and starter motor while i'm in there, but if I can just clean the ICV and save almost $800, all the better!

[Alexei9012]

Originally Posted by pathall1

Did you ever clean this? Curious as to your results. Planning on doing my throttle actuators soon and would like to also address this and starter motor while i'm in there, but if I can just clean the ICV and save almost $800, all the better!

Cars in for NRW Design valve covers at the moment, getting them to clean the ICV, so will update soon

[Alexei9012]

Originally Posted by pathall1

Did you ever clean this? Curious as to your results. Planning on doing my throttle actuators soon and would like to also address this and starter motor while i'm in there, but if I can just clean the ICV and save almost $800, all the better!

Got the car back today, so far it seems cleaning has fixed it, had no rough idles, or RPM needle bouncing around!

I’ll keep updated if it reverts

[UPSROD]

Originally Posted by t_win

While you're in there might as well do the throttle actuators if you haven't yet.

He doesn't state the milage that I saw, which is the main factor on the throttle actuators!

[mjn77]

Is there a DIY for cleaning the ICV?

[yardbro]

Originally Posted by mjn77

Is there a DIY for cleaning the ICV?

There are certainly DIYs out there for how to remove and replace the ICV. Other than that, you would clean and treat this the same way you would a standard butterfly throttle body.

You are really just aiming to ensure that there isn't any carbon buildup obstructing the butterfly plate in the bore around where it seals. No reason you couldn't clean it with throttle body cleaner or brake cleaner and some q tips.

[nleeumd]

Originally Posted by mjn77

Is there a DIY for cleaning the ICV?

Good ol' M539 @16:07

[GinTonic]

Replace fuel breather valve first. My problems went away once I replaced this.

[mjn77]

Originally Posted by GinTonic

Replace fuel breather valve first. My problems went away once I replaced this.

Yeah, i already did and made no difference.

[yardbro]

Originally Posted by mjn77

Yeah, i already did and made no difference.

Have you tried cleaning the ICV yet or running the test plan in ISTA? After that, I'd take a look at live data and see what the MAP sensor is showing. There aren't really many other things left that could be doing this.

[mjn77]

Originally Posted by yardbro

Have you tried cleaning the ICV yet or running the test plan in ISTA? After that, I'd take a look at live data and see what the MAP sensor is showing. There aren't really many other things left that could be doing this.

Not yet, going in the garage next week as the prop shaft CV joint needs replacing as well.

[yardbro]

Originally Posted by mjn77

Not yet, going in the garage next week as the prop shaft CV joint needs replacing as well.

Got ya. Let us know what they find.

[mjn77]

Originally Posted by yardbro

Got ya. Let us know what they find.

So, had the ICV replaced about 4 weeks ago and straight away, it starts much better. However, as of now, the cold start splutter is back. So either the new ICV has gone bad, or it is something else?

[a5m]

Vacuum leak maybe?