[MSpeedAddict]

Did I really spell included wrong?
So I had the car smoke tested last summer when this issue developed - and fixed very minor leaks and sealed up the injectors.

The idle issue is worse in the summer, and combined with the idle drop issue that many experience the car will stall out when coming to a stop in neutral (only go in neutral right before a dead stop, tried putting it in neutral early but no difference), usually in hot weather.

Car is alpha-n tuned, leaks should not matter for the most part.

Car does run lean at idle, but under acceleration and WOT the air/fuels are very good.

If I hold the idle at 1100, there are no hiccups and the car runs perfectly (great) throughout the powerband just not at idle.

I have replaced fuel pump, fuel filter, spark plugs, injectors, vacuum lines, etc, everything that I could possibly believe to be related to the idle.

A member on here had me call him and suggested a vacuum as oppose to a pressure test. I'm looking into doing this ASAP.

I have cleared adaptations multiple times. Sometimes it will help for some miles but then return or sometimes it will come back right away.

Before I get to the videos, when working on the car today and changing up some things described below I had left the ICV unplugged by mistake. I went for a drive and every time when coming to a stop the car would stop PERFECTLY without ANY DIP WHATSOEVER at 1400rpms. I drove around for 10 minutes like this and I thought maybe the car had adapted or something so I went to go home and the car went into limp mode. I restarted the car and drove home fine without issue.

In INPA I checked adaptations and they were still zero'd out, all other numbers looked fine and then I remembered that I did not plug the ICV back in.

To the videos, taken today.

Part 1:
Thought I may had found the source of my idle issue, the 2" hose on the ICV was torn and I replaced it. Car had been idling perfect for a while directly before this video, I was waiting to see how far the vacuum would build up (ususally starts at -17 and builds to ~-21) and it made it all the way to -23 steady and was idling perfect and I was about to go on a drive when all of a sudden the car stuttered once and the air/fuels started fluctuating a full point (you can feel the oscillation in the car)

Part 2:

After the bad idle re-developed in video 1 after replacing hose on icv and adaptation reset, i rev'd the car in neutral to see if the bad idle rev'ing would occur with the vacuum oscillation as well. Rev'd up to 1.5k and let go and of course the idle started hunting, as well as the vacuum and lean air/fuel.

E46 M3 Bad Idle After Adaptation Reset and Hose Replacement PART 1 - YouTube

E46 M3 Bad Idle After Adaptation Reset and Hose Replacement PART 1 - YouTube

E46 M3 Bad Idle After Adaptation Reset and Hose Replacement PART 2 - YouTube

E46 M3 Bad Idle After Adaptation Reset and Hose Replacement PART 2 - YouTube

Anybody have any ideas?
I spoke with Zak @ Active Autowerke on Thursday and he is going to review my tune on file and see if there are any adjustments he can make to improve the idle.

At this point after dealing with this for so long I am completely fed up and beside myself and the stalling out in traffic (some would say thats embarrassing) is actually a safety risk as when pulling onto a main road and if the car is in neutral just long enough for the RPMs to reach idle speed the car will stall and the power steering will go out. Completely dangerous and as it happened once with my girlfriend in the car I will not drive with her again until this is resolved.

[Zengim3er]

Have you done a compression test at all? With the problems you've listed as fixed, and the forced induction, you may have had some detonation issues.

[MSpeedAddict]

Originally Posted by Zengim3er

Have you done a compression test at all? With the problems you've listed as fixed, and the forced induction, you may have had some detonation issues.

I'll have to see if a compression test was done when the long block was replaced. That said, wouldn't I have issues other than a rough idle? Their are no issues or 'roughness' etc while driving.

That, and when the ICV was disconnected and idle rpm was raised, both the idle dip and rough idle were eliminated.

[MSpeedAddict]

Bump

[kmfurdm]

Have you asked in the FI section?

[MSpeedAddict]

Originally Posted by kmfurdm

Have you asked in the FI section?

A while ago, my thread didn't get any traction.
I may post a link to this thread in that section.

[Hrvat]

What's your idle set at? I had the similar issue after SC-ing my 330i. Was worse in the summer then winter. With SC being added to belt system, it added extra strain and base idle wasn't high enough anymore. VF raised the idle by 80 rpm I believe and fixed the problem

[Ramp1]

Have you tried cleaning the idle air control valve out with throttle body cleaner spray? It could be working but gummed up and so it's constantly adjusting trying to keep the idle where it should be. It seems like a very mild issue, not as bad as the dirty MAF idle issue. Has the car ever stalled out or does it just fluctuate like that?

[MSpeedAddict]

Originally Posted by Hrvat

What's your idle set at? I had the similar issue after SC-ing my 330i. Was worse in the summer then winter. With SC being added to belt system, it added extra strain and base idle wasn't high enough anymore. VF raised the idle by 80 rpm I believe and fixed the problem

Yeah, Zak @ AA is looking into this. I firmly believe at this point that it is software related.

Originally Posted by Ramp1

Have you tried cleaning the idle air control valve out with throttle body cleaner spray? It could be working but gummed up and so it's constantly adjusting trying to keep the idle where it should be. It seems like a very mild issue, not as bad as the dirty MAF idle issue. Has the car ever stalled out or does it just fluctuate like that?

I've cleaned the ICV as well as check valves. They were gunked up when I pulled them a couple months ago. I have since pulled them both twice, ensured they were still clean (they were spotless) and reinstalled them.

Coinage actually lent me a working ICV to swap, I thoroughly cleaned and swapped and the issue still exists. (see above OP where I left the ICV unplugged, this was his ICV that I accidentally left unplugged)

[calvinf1]

From watching the video, it seems like the ICV is still the issue (because as soon as you let go of the gas, the car has trouble finding an idle spot). I know Matt gave you an ICV to do a swap test, but was his ICV old/used? I asked because I went through the same problem as you did. After I started experiencing idling issue, I went to buy a ICV off of a partout are that was ran perfect according to the seller. I swapped it and I was still experiencing the same issues. At that point I didn't think that it was an ICV and started swapping coils and plugs and things like that. At the end, I just went on amazon and bought an ICV for about a hundred bucks just to try it out one more time (as a last resort before to decided to get rid of my SC). And turns out that the brand new ICV fixed the idling issue... no more rough cold starts, stalling at neutral, stalling at a stop light, stalling when turning the AC on/off, and most important of all, I once again gained confident in driving my car.

I truely believe you need to order a new ICV and try that before you eliminate that as the source of your issue. (and do an adapt reset after the swap)