[95blkmax]

are you guys (burr and Willy) on the original coils?

I think it was burr that said you started getting this at 83k and still now. At that 83k N55s don't have THAT much CBU to merit that cold-start behavior (if it was an N54 I'd say heck that's your problem right there LOL).

I had a shaky idle and cold start ever since I started modding right after i bought the car at 109k. It got worse as we got into the summer heat. Felt like a misfire but I had no codes. I changed the plugs to N20 NGKs (FCP!) gapped down- it got better but still noticeable. I bit the bullet and got a set of Eldor coils (FCP again!) and BUTTER SMOOTH. Not a single twitch in cold start or idle (cold or heatsoaked). Rock steady.

[95blkmax]

Originally Posted by SWFLf10

Another thing to look into is the vanos solenoids mounted to the front of the engine. I know on a previous BMW of mine that they caused an RPM issue when starting the car when they were starting to go bad.

This is a good point too! And it's not too hard to pull these and clean them out. Put new gaskets and back in they go.

[WildWilly1100]

Originally Posted by SWFLf10

Another thing to look into is the vanos solenoids mounted to the front of the engine. I know on a previous BMW of mine that they caused an RPM issue when starting the car when they were starting to go bad.

Thanks for this, started the car today after sitting for a few days and the RPM dropped to around 600, so I guess the intake is not the issue. Will talk to my mechanic about the solenoids. Thx.

[BurrNinja]

Originally Posted by 95blkmax

are you guys (burr and Willy) on the original coils?

I think it was burr that said you started getting this at 83k and still now. At that 83k N55s don't have THAT much CBU to merit that cold-start behavior (if it was an N54 I'd say heck that's your problem right there LOL).

I had a shaky idle and cold start ever since I started modding right after i bought the car at 109k. It got worse as we got into the summer heat. Felt like a misfire but I had no codes. I changed the plugs to N20 NGKs (FCP!) gapped down- it got better but still noticeable. I bit the bullet and got a set of Eldor coils (FCP again!) and BUTTER SMOOTH. Not a single twitch in cold start or idle (cold or heatsoaked). Rock steady.

I'm on same coils yeah I havent dug into the problem. One of these days I will change them out .

[WildWilly1100]

As the colder weather has come on, the cold start issue has now moved on to rough running for about the first 10 minutes until warm. Not really rough, but enough that it feels like the tires are out of balance. Going to do the VANOS solenoids next week, will report back.

[ryansbmw]

Originally Posted by WildWilly1100

As the colder weather has come on, the cold start issue has now moved on to rough running for about the first 10 minutes until warm. Not really rough, but enough that it feels like the tires are out of balance. Going to do the VANOS solenoids next week, will report back.

Any luck with this? My n55 is stuttering/stalling out on the first cold start of the day only, (colder the temp, the worse it is) but I’m not getting any codes or CEL on the dash. Back on New Years, I finally got 2D55, 2C58, and 2774. Cleared hem and drove 6 hrs without issue. This was the one and only time I’ve gotten a code pointing towards something but not sure if it will actually solve the problem.

[Bmwfan55]

I have had the same issue for a few years by now on my n55. Did everything go the car, spark plugs, both fuel pumps, vanos solenoids, maf/map sensors, fuel filter, injectors, solenoids, valve cover and gasket, and I'm sure I'm forgetting some other things. I could never got rid of the cold start issue. It did get better in the sense that rpms don't dip lower than 1000 now, but still bounces on cold start. I have prob invested a good 6 to 8k on trying to make the car start right, to no avail. Only think left to try is walnut blasting.

[mashpotato]

Check if there is any extra power draw on the system. I had a shorted door handle that eventually blew the fuse, but before that I had a similar idle problem.

[WildWilly1100]

Originally Posted by ryansbmw

Any luck with this? My n55 is stuttering/stalling out on the first cold start of the day only, (colder the temp, the worse it is) but I’m not getting any codes or CEL on the dash. Back on New Years, I finally got 2D55, 2C58, and 2774. Cleared hem and drove 6 hrs without issue. This was the one and only time I’ve gotten a code pointing towards something but not sure if it will actually solve the problem.

I replaced the VANOS solenoids and it made no difference, talked to a top level MB tech and he says two things to do. 1) a good cleaning of the throttle body plates with the correct type of cleaner, sometimes they can get sticky with age, 2) go for the intake cleaning, start with a fuel system service, then go to walnut blasting if needed. Will look into these two things in the spring.

[Bmwfan55]

Originally Posted by WildWilly1100

I replaced the VANOS solenoids and it made no difference, talked to a top level MB tech and he says two things to do. 1) a good cleaning of the throttle body plates with the correct type of cleaner, sometimes they can get sticky with age, 2) go for the intake cleaning, start with a fuel system service, then go to walnut blasting if needed. Will look into these two things in the spring.

Just replaced the camshaft position sensors, fresh oil change and vanos cleaning. I am amazed of how smooth the car starts on cold mornings! Hope this helps you

[Boosted M5]

Forgot where I read this but someone posted that it could be a vacuum leak. Not sure exactly from where. I have a 550i btw. Mine does the same thing. When the engine is not at operating temp, the idle is at 750. Once the engine is warm Rpms drop to 500ish and go up to 750 if the a/c is on.

[Bmwfan55]

Originally Posted by Boosted M5

Forgot where I read this but someone posted that it could be a vacuum leak. Not sure exactly from where. I have a 550i btw. Mine does the same thing. When the engine is not at operating temp, the idle is at 750. Once the engine is warm Rpms drop to 500ish and go up to 750 if the a/c is on.

True. I did have a vacuum leak that got fixed. But didn't fix the cold start issue. I'm all honestly, It could be a lot of things, but believe me when I Tell you I tried and fixed them all and that was the only solution I could find. In my case those Sensors didn't throw any specific faults, after much research I replaced them and now car runs perfect.

[WildWilly1100]

Originally Posted by Bmwfan55

Just replaced the camshaft position sensors, fresh oil change and vanos cleaning. I am amazed of how smooth the car starts on cold mornings! Hope this helps you

Thanks for this info, those sensors don't seem to be too expensive, I'll give that a try and see what happens, we've already replaced the vanos solenoids and it's getting an oil change tomorrow. Will report back, once this is done. Thx.

[arshakadelic]

Originally Posted by WildWilly1100

Hi guys, Kinda new here and new to the F10, owned for about a year now. In the last few months, when starting the car cold, RPM will hit 1100-1200, then drop to 500 and a few seconds later, rev up to 1500, then settle in back at 1000 or so and away you go. Only does it on cold (not winter cold) start. Any ideas??

115,000 kms, N55.

Thanks.

Are you shifting to reverse right away ? Mine does that when I'm in a rush and put it into gear right after a cold start. I've stopped since and it's been fine.

[WildWilly1100]

Originally Posted by arshakadelic

Are you shifting to reverse right away ? Mine does that when I'm in a rush and put it into gear right after a cold start. I've stopped since and it's been fine.

No, I'm not shifting right away, usually wait about 30 seconds before I go anywhere. Replacing the cam shaft sensor this week to see if that helps. Will let you all know how that goes.

[Bmwfan55]

Originally Posted by WildWilly1100

No, I'm not shifting right away, usually wait about 30 seconds before I go anywhere. Replacing the cam shaft sensor this week to see if that helps. Will let you all know how that goes.

Please do. I hope you have the same luck than me

[Bmwfan55]

Originally Posted by WildWilly1100

No, I'm not shifting right away, usually wait about 30 seconds before I go anywhere. Replacing the cam shaft sensor this week to see if that helps. Will let you all know how that goes.

After a week and change, RPM drop at cold start came back again. Not as severe as before, but noticeable. I give up on this car, all I've done is to maintain it right and all it gives me is headaches. Hope you have better luck than me.

[WildWilly1100]

Originally Posted by Bmwfan55

After a week and change, RPM drop at cold start came back again. Not as severe as before, but noticeable. I give up on this car, all I've done is to maintain it right and all it gives me is headaches. Hope you have better luck than me.

They do have their quirks, but I have to say, when I'm cruising down the highway, all is forgiven. I just love everything else about these cars and will suffer through the odd issue that drives me nuts. Also, just picked up a 2015 650i xDrive convertible, looking forward to enjoying that once the snow melts.

[Bmwfan55]

Originally Posted by WildWilly1100

They do have their quirks, but I have to say, when I'm cruising down the highway, all is forgiven. I just love everything else about these cars and will suffer through the odd issue that drives me nuts. Also, just picked up a 2015 650i xDrive convertible, looking forward to enjoying that once the snow melts.

True. They do have excellent driving dynamics

[WildWilly1100]

So we just replaced the cam sensor and the spark plugs. 3 of the plugs were a nice tan color as expected, however, 3 were boot polish black, obviously running rich on those 3 cylinders. Could be injector issues, but we're trying some injector cleaner through the gas tank first. Will run seafoam for the next few tanks and see what happens. However, the new plugs did make it better, so fingers crossed for the injector cleaner. Will update again in a few weeks. We'll also pull the plugs at the next oil change and have a look see.

[Bmwfan55]

Originally Posted by WildWilly1100

So we just replaced the cam sensor and the spark plugs. 3 of the plugs were a nice tan color as expected, however, 3 were boot polish black, obviously running rich on those 3 cylinders. Could be injector issues, but we're trying some injector cleaner through the gas tank first. Will run seafoam for the next few tanks and see what happens. However, the new plugs did make it better, so fingers crossed for the injector cleaner. Will update again in a few weeks. We'll also pull the plugs at the next oil change and have a look see.

Best of lucks. If you need injectors, get them at fpc euro or ecs tuning. You'll have to pull one out and check the number on them.

[WildWilly1100]

Originally Posted by Bmwfan55

Best of lucks. If you need injectors, get them at fpc euro or ecs tuning. You'll have to pull one out and check the number on them.

Thanks, I've already looked on ecs site. But this morning, she barely dipped below 1,000 rpm, so it is definitely getting better. ½ a tank to go, then fill up again with seafoam. Also, went for a drive yesterday using manual mode and kept it above 3,000 rpm on the highway for a while.