[beamlord]

Originally Posted by ztx84

Mine is exactly the same as yours - RPMs vary a little bit hot or cold, gauge jumps just a little bit (but you really have to look to see it). I figure as long as it pulls correctly, starts and drives as it should, then its all normal. Nothing to worry about I don't think

Check the youtube video I posted. Apparently it's not normal, since that car in the video doesn't do that, despite of idling for 15 minutes straight I can't see one single movement of the gauge.
That should have us worried..no?

[vasillalov]

Not having experienced it myself with S58, but having owjed a highly modified N54, this sounds like misfires at idle. The MSD80 and later ECUs have "Rough Running" control settings. They are adaptive and I believe fairly normal for direct injection engines. I would count it as normal.

On my N54, new spark plugs every 10K miles do wonders.

[beamlord]

Originally Posted by vasillalov

Not having experienced it myself with S58, but having owjed a highly modified N54, this sounds like misfires at idle. The MSD80 and later ECUs have "Rough Running" control settings. They are adaptive and I believe fairly normal for direct injection engines. I would count it as normal.

On my N54, new spark plugs every 10K miles do wonders.

So the "rough running" is a sort of a mode that may have been set on purpose?

[vasillalov]

Originally Posted by beamlord

So the "rough running" is a sort of a mode that may have been set on purpose?

If the driver perceives rough running, you can use BMW software to diagnose from which cylinder it is coming from. The software displays all 6 cylinders and a range of how each cylinder is doing. You can reset values but unless you've fixed the problem, it will occur again.

This "rough running" on N54 can be caused by many things: sticking injector, ignition coil that's randomly not releasing all the charge, worn out spark plug, etc. If a cylinder misses an ignition cycle, the DME will detect that, and usually the cure is to raise the idle a bit till it detects that everything is good.

Remember, 600rpm means 10 crank rotations per second. If there is a single misfire event, you'll only notice a small hick-up followed by an rpm change.

At least this is now things are on the N54. I am not sure exactly how this works on S58 so take everything above as nothing more than a theory.

[vasillalov]

Also, one other thing I wanted to mention, in North America, we do not have OPF system like in the rest of the world. I am not exactly sure how this works, but it could be related to DME making adjustments for emissions purposes and this comes out as "unsteady" idle.

[beamlord]

Originally Posted by vasillalov

Also, one other thing I wanted to mention, in North America, we do not have OPF system like in the rest of the world. I am not exactly sure how this works, but it could be related to DME making adjustments for emissions purposes and this comes out as "unsteady" idle.

Wish this were the case. But the OP and others who mentioned the exact same thing, are all in the US so can't be OPF.

This issue seems to be the same both in US and Europe. I have seen it on German forum as well.

I have a much stronger concern regarding long crank when hot issue which happens intermittently. And on engine stumble when cold.
And wondering if rough idle is just another symptom of that (i.e. injector failure)..

[vasillalov]

The S58 uses the same injectors as B58. The injector issues were sorted out way back with the N55 engines. I don't think it's an issue here.

[beamlord]

Originally Posted by vasillalov

The S58 uses the same injectors as B58. The injector issues were sorted out way back with the N55 engines. I don't think it's an issue here.

Apparently, unfortunately not sorted at all:

https://g80.bimmerpost.com/forums/showthread.php?t=1940488

[vasillalov]

Oh wow. I have not seen this.

[beamlord]

Originally Posted by vasillalov

Oh wow. I have not seen this.

Yep. And it very much looks like I am doomed with the same issue.

Unless it magically turns out to be, in my case, caused by a weak battery, which I definitely have as well.

[mirob]

It's cammed.

[Shaneartistry]

Originally Posted by vasillalov

Oh wow. I have not seen this.

Looking like I have the same issue with a faulty fuel injector as well. I have an appointment on the 12th. Most notable symptom is long crank after the engine is warm, almost like the car doesn’t want to start. Sometimes strong gasoline smell as well after the long crank. I’ve noticed “bouncy” rpm as well, but initially thought it was just how the M3 was. Now I’m wondering if it’s related to a bad fuel injector.

[M4_ZMT]

OP checking back in. I have had the break-in service as well as the one year oil service (Don't judge me but I have tandem parking and I treat this thing like my special occasion Ferrari, but I only have about 1,700 miles on her)...but it has remained the same. It just kinda burps a lil' here and there, I truly do think it's normal or people just don't notice it. You can hear it happening as well if you are outside the car with the engine running and near the exhaust. Seems people have reported the same on 6MT and Comp so that doesn't seem to be a factor. ALSO, I find it very possible with that video of the iDrive 8 car, that BMW has added some sort of compensation to this so that it doesn't appear to the driver that the idle is fluctuating...Because it can be THAT subtle where if the tach didn't show me, I may not have even noticed at times, when it is warmed up especially, when cold would just chock it up to that.

Ok, so I don't know for sure, but I don't think the long crank is related to the possible fuel injector thing. Because my crank is 100% normal, starts up right away even after sitting (I do use a battery tender at times for what it is worth). It would be interesting to see if anyone with an iDrive 8 equipped G8X has this rev bounce, or at least has it displaying as fluctuations in the cluster. Mine has 7 and the tach does visibly do it's little thing but since it's simply a screen, I can see them adjusting the display refresh settings when at idle to not reflect this. The interesting this is that a non M (the ones I've seen) w/ iD7 don't have a fluctuation, but again, not an M and I know M idles can be a little extra. Maybe they can fix at least the way it is being displayed via software at some point. This is all speculation, but interesting the one video of a G8X not doing it, is with iD8.

The plot thickens...but with no performance issues, I can't really imagine it being ABnormal...but I just think we would have seen more documentation at this point. I am a very picky/astute type of person so leave it up to me to find something odd that probably is normal.

[beamlord]

Originally Posted by M4_ZMT

OP checking back in. I have had the break-in service as well as the one year oil service (Don't judge me but I have tandem parking and I treat this thing like my special occasion Ferrari, but I only have about 1,700 miles on her)...but it has remained the same. It just kinda burps a lil' here and there, I truly do think it's normal or people just don't notice it. You can hear it happening as well if you are outside the car with the engine running and near the exhaust. Seems people have reported the same on 6MT and Comp so that doesn't seem to be a factor. ALSO, I find it very possible with that video of the iDrive 8 car, that BMW has added some sort of compensation to this so that it doesn't appear to the driver that the idle is fluctuating...Because it can be THAT subtle where if the tach didn't show me, I may not have even noticed at times, when it is warmed up especially, when cold would just chock it up to that.

Ok, so I don't know for sure, but I don't think the long crank is related to the possible fuel injector thing. Because my crank is 100% normal, starts up right away even after sitting (I do use a battery tender at times for what it is worth). It would be interesting to see if anyone with an iDrive 8 equipped G8X has this rev bounce, or at least has it displaying as fluctuations in the cluster. Mine has 7 and the tach does visibly do it's little thing but since it's simply a screen, I can see them adjusting the display refresh settings when at idle to not reflect this. The interesting this is that a non M (the ones I've seen) w/ iD7 don't have a fluctuation, but again, not an M and I know M idles can be a little extra. Maybe they can fix at least the way it is being displayed via software at some point. This is all speculation, but interesting the one video of a G8X not doing it, is with iD8.

The plot thickens...but with no performance issues, I can't really imagine it being ABnormal...but I just think we would have seen more documentation at this point. I am a very picky/astute type of person so leave it up to me to find something odd that probably is normal.

I just put on over 1700 miles in less than two weeks, half of them spirited driving and track 😃
Anyway, my car is ID8 and the idle fluctuates just the same as you describe, and I do feel light shudder from time to time.
And I have the long crank, as well as stumble and die on cold start already a few times.

The car performs flawlessly otherwise, the engine took a 3 day long beating at the track going all the way.

[M4_ZMT]

Originally Posted by beamlord

I just put on over 1700 miles in less than two weeks, half of them spirited driving and track 😃
Anyway, my car is ID8 and the idle fluctuates just the same as you describe, and I do feel light shudder from time to time.
And I have the long crank, as well as stumble and die on cold start already a few times.

The car performs flawlessly otherwise, the engine took a 3 day long beating at the track going all the way.

Shoot, there goes my theory. So I have a normal crank just the idle thing and def flawless performance. So strange! LOL- I hope we can get some sort of answer at some point, what an odd thing. Anyway, thanks everyone for helping bump the thread as it’s definitely good to hear everyone else’s experience! I’m still feeling that it’s normal for an S58, then I drove an X3 M and it didn’t at all haha! Jeez, I would’ve expected an information only SIB by now if it were but maybe we’re all just super astute towards our rides.

[beamlord]

Originally Posted by M4_ZMT

Shoot, there goes my theory. So I have a normal crank just the idle thing and def flawless performance. So strange! LOL- I hope we can get some sort of answer at some point, what an odd thing. Anyway, thanks everyone for helping bump the thread as it’s definitely good to hear everyone else’s experience! I’m still feeling that it’s normal for an S58, then I drove an X3 M and it didn’t at all haha! Jeez, I would’ve expected an information only SIB by now if it were but maybe we’re all just super astute towards our rides.

That's the problem, x3m, other m3/m4 I have seen don't have this issue. They have steady idle. So it's definitely not normal.

By the way, can you measure your resting battery voltage? Engine off, use the jump start connectors under the hood.
I have another theory that the weak battery may be causing the floating idle..

[vasillalov]

Unfortunately, this sounds like a deja-vu from the N54 days. Sad to see this happening 3 generations of turbo I6 engines later.

[beamlord]

Originally Posted by vasillalov

Unfortunately, this sounds like a deja-vu from the N54 days. Sad to see this happening 3 generations of turbo I6 engines later.

Since they are in principle similar engines, how intrusive is the job to replace the fuel injectors?
For example, does cooling system or charge cooler need to be drained or stays on?

[M4_ZMT]

Originally Posted by beamlord

That's the problem, x3m, other m3/m4 I have seen don't have this issue. They have steady idle. So it's definitely not normal.

By the way, can you measure your resting battery voltage? Engine off, use the jump start connectors under the hood.
I have another theory that the weak battery may be causing the floating idle..

Many seem to also have it, (idle concern), but not any of the other symptoms, like myself, which is extremely odd. So most people are having long cranks when the vehicle is warm only? I can check that. Since my car doesn't get driven very often, when I take it out, I usually will run it a good 50-60 miles (88km) without shutting it off and restarting before it gets turned off in my garage. Next time I drive it I will try to do a restart while warm.

I don't have a multimeter at the moment, but I will order one promptly as I didn't realize I was without this garage essential tool. For further info, I do regularly use the rebranded BMW C-Tek trickle charger.

Do you mind taking a video of your idle and that long crank at warm by chance? I will do as soon as I can drive it as it is currently blocked in garage. Thank you for your detailed analyses of these possibly related/but not confirmed issues, and now people are having a failing injector. I just wonder if the people that are claiming rough idle with a failed injector are referring to a VERY extreme rough idle and not the, for lack of a better word "small burps" that I experience, and very slight up and down movement also heard from exhaust on exterior. I know that doesn't explain the videos of some cars not doing it...but I think we need more videos of the tach of G8X S58 engines idling once warm...the more we see the more we can determine normality or not. A lot can change in a I-Step version, I haven't even gotten the most recent OTA and it's possible it exists in certain versions and not in others, granted we are also comparing US vs Euro spec.

[beamlord]

Originally Posted by M4_ZMT

Many seem to also have it, (idle concern), but not any of the other symptoms, like myself, which is extremely odd. So most people are having long cranks when the vehicle is warm only? I can check that. Since my car doesn't get driven very often, when I take it out, I usually will run it a good 50-60 miles (88km) without shutting it off and restarting before it gets turned off in my garage. Next time I drive it I will try to do a restart while warm.

I don't have a multimeter at the moment, but I will order one promptly as I didn't realize I was without this garage essential tool. For further info, I do regularly use the rebranded BMW C-Tek trickle charger.

Do you mind taking a video of your idle and that long crank at warm by chance? I will do as soon as I can drive it as it is currently blocked in garage. Thank you for your detailed analyses of these possibly related/but not confirmed issues, and now people are having a failing injector. I just wonder if the people that are claiming rough idle with a failed injector are referring to a VERY extreme rough idle and not the, for lack of a better word "small burps" that I experience, and very slight up and down movement also heard from exhaust on exterior. I know that doesn't explain the videos of some cars not doing it...but I think we need more videos of the tach of G8X S58 engines idling once warm...the more we see the more we can determine normality or not. A lot can change in a I-Step version, I haven't even gotten the most recent OTA and it's possible it exists in certain versions and not in others, granted we are also comparing US vs Euro spec.

Yes, please do that. It's not really a warm start, but more like - have the car get to full operating temperature, after your usual drive. Then leave it for awhile - don't start it up immediately. Something like 20-30 minutes, seems to be the time. And then start it.

My idle is exactly as you describe - very light shaking of the needle, and really just very seldom something that I can actually feel i.e. shudder, and barely noticeable.

Whether the idle and fuel injectors are related, we will hopefully know soon when my car is brought in next week.

But the original poster in another thread actually said his idle was fixed after replacing the injector. So I am hoping this is related.

[FISH22]

My G80 has exhibited choppy idle for quite some time now. Mostly smooth, but it will do the occasional burp (what almost feels like a miss). Did this when the car was bone stock, and still after being modified; intake and full exhaust.

The car starts like a champ though, and runs flawlessly. She’s coming up on 18k miles and has not blown up yet.

[vasillalov]

Originally Posted by beamlord

Since they are in principle similar engines, how intrusive is the job to replace the fuel injectors?
For example, does cooling system or charge cooler need to be drained or stays on?

I was probably the first person on E90post to create a DIY for replacing the N54 injectors AND the process for coding them in so that the ECU can operate them properly. The N54 injectors rely on piezoelectric components and thus there are slight deviations that naturally happen during manufacturing. As such N54 injectors need to be coded in. I created a DIY manual and video about it.

I have no clue how this process works for B58 and S58 engines.