[muncie21]

I have a slight misfire/rough idle on warm restart. This is with heater/AC off. Not enough of a miss to trigger a code or CEL, but noticeable none the less.

BTW, I have all new plugs and coils, still does it.

[bimmbo]

I have the N52, but figured it might be the same issue for you guys. Similar rough idle and engine stutter issues that were resolved by cleaning out the eccentric shaft sensor connector. Will need to replace the seal at some point, just wanted to be sure before buying parts. Here's my OP:
http://www.e90post.com/forums/showth...0#post20298100

[speculator]

Originally Posted by speculator

Hello all, I have some cold idle problems in my 325i ’08.

- After cold start rpms jumps up to 1000-1100rpm for a couple of seconds and then rpms keeps hunting to 600-700 rpm
- HPFP replaced recently
- car is shaking a little bit when engine is cold
- when the engine warms up a little bit, idle is very smooth and there’s no problems at all
- spark plugs replaced about 6000 miles ago

- error codes:
o 29F3 low pressure fuel sensor
o 2B05 NOX sensor, heating

Note that the car is 325i (mileage 85 000 miles) with naturally aspirated n53b30-U0 engine (euro model). I think that error codes above have not to do with the cold idle problems, because no misfire codes occurred and warm engine runs very smoothly.

So I decided to change all six injectors and see what happens, because no injectors have been changed before. Any comments or ideas?

I decided to change all of the 6 injectors. Now after two cold starts everything seems to be ok. Engine is running very smooth -no shaking or rpm hunting occurs anymore. Actually, the engine runs perfectly!

However, the local BMW service wanted to change 4 coils at the price of 114€/piece, because according to them "4 coils is broken". I decided not to change them and maintain in the original plan and change the injectors first. Now the engine runs perfectly, what do you think I should do with the coils?

To my mind, if 4 coils are broken, the engine won't even start. Or at least, there must be some issues if 4 coils is broken? I don't want to change unbroken parts...

Thank you in advance for your answer.

[dazz100]

Hi

I have/had this problem.
Took it to the dealer (first time ever).
The engine reported a rough idle on cylinder 4. The swapped the spark plug with cylinder 2.
The engine reported a rough idle with cylinders 2 and 4.

They found a fault with the No.4 coil and a defective spark plug. Replacing the coil and all spark plugs fixed the problem. Price was $NZD650.

I suspect that a rough idle can be caused by a number of "common" faults.
HPFP, fuel pressure regulator, injectors, air leaks, spark plugs and coils. That would explain why there is no simple answer.

[E92Wagon]

Our E91 wagon (2012 MY; 30K miles) had numerous rough idling/hesitation at startup. The BMW dealer couldn't figure it out until CYL5 coilpack failed. Car fixed under warranty - no questioned asked - all 6 coils replaced. I talked to the SM and mechanic - the solution was to not replace with Bosch coils but with (better) Delphi coils. Interesting since RX-8 owners (me) also have far better coil life with Delphi (LS) coils installed.

After reading my Berkeley shop manual - realized that the coil (heading to) failure may have been diagnosed by using an oscilloscope since the coil must have a minimum # of misfires prior to throwing the P code.

[AWD Addict]

I'm approaching 100k miles, and I'd offer the following based on my obnoxious level of study on this matter.

1) Run good gas. It's not all the non-brands, but some of them definitely do have a bad effect on idle, and sometimes it takes a tank or two of good gas for it to go away.
2) plugs, coil packs and injectors, in no particular order have been/can be culprits.
3) I did not find the walnut blast effective on this issue. The car certainly runs way better if you're cleaned every 40k or so, but after a few of them, I don't attribute any change int he rough idle and rpm movement to it.
4) Techron is a complete waste of time and money in a DI car. Stop wasting your money. I actually think the fuel cleaner could be part of the problem (two times my mechanic ran it for me as a "favor" and my car ran like shit for weeks). All it did was disturb deposits, and run them through a super-sensitive system. Just leave it alone. It won't even clean the injectors, which is the only reason you'd run Techron in the first place.
5) Intake system issues could also be a part of the problem. Our plastic manifolds are crappy, and can crack and be invisible. I've had 3 smoke tests identify 3 separate issues that dramatically improved my car's idle. Charge pipe crack, leaking inlet on the turbo (I'm starting a thread on that soon), and valve cover gasket breach. All were invisible until we smoke tested.

Bottom line, this engine is tuned tighter than a dolphin's ass, and it's likely not just one thing that can cause it to run a bit. This is primarily an issue of a German over engineered system. If one gnat's asshair is out of place, a driver that is tuned into their automobile will notice it. If a few are out of place, your blind, deaf aunt will notice.

Thanks to all contributing to this thread. We're lucky to have such an involved and thoughtful community.

AA

[!LEFTCOAST!]

^^^ Tell me about it! This car knows how to test your patience as well as your wallet. Lol!

[Sgop335]

Originally Posted by AWD Addict

I'm approaching 100k miles, and I'd offer the following based on my obnoxious level of study on this matter.

1) Run good gas. It's not all the non-brands, but some of them definitely do have a bad effect on idle, and sometimes it takes a tank or two of good gas for it to go away.
2) plugs, coil packs and injectors, in no particular order have been/can be culprits.
3) I did not find the walnut blast effective on this issue. The car certainly runs way better if you're cleaned every 40k or so, but after a few of them, I don't attribute any change int he rough idle and rpm movement to it.
4) Techron is a complete waste of time and money in a DI car. Stop wasting your money. I actually think the fuel cleaner could be part of the problem (two times my mechanic ran it for me as a "favor" and my car ran like shit for weeks). All it did was disturb deposits, and run them through a super-sensitive system. Just leave it alone. It won't even clean the injectors, which is the only reason you'd run Techron in the first place.
5) Intake system issues could also be a part of the problem. Our plastic manifolds are crappy, and can crack and be invisible. I've had 3 smoke tests identify 3 separate issues that dramatically improved my car's idle. Charge pipe crack, leaking inlet on the turbo (I'm starting a thread on that soon), and valve cover gasket breach. All were invisible until we smoke tested.

Bottom line, this engine is tuned tighter than a dolphin's ass, and it's likely not just one thing that can cause it to run a bit. This is primarily an issue of a German over engineered system. If one gnat's asshair is out of place, a driver that is tuned into their automobile will notice it. If a few are out of place, your blind, deaf aunt will notice.

Thanks to all contributing to this thread. We're lucky to have such an involved and thoughtful community.

AA

Interesting you talk abour techron. I used to add redline si1 only to find timing corrections. Now i dont and no timing corr, still a mystery to je.

[dlbrooks18]

Originally Posted by AWD Addict

I'm approaching 100k miles, and I'd offer the following based on my obnoxious level of study on this matter.

1) Run good gas. It's not all the non-brands, but some of them definitely do have a bad effect on idle, and sometimes it takes a tank or two of good gas for it to go away.
2) plugs, coil packs and injectors, in no particular order have been/can be culprits.
3) I did not find the walnut blast effective on this issue. The car certainly runs way better if you're cleaned every 40k or so, but after a few of them, I don't attribute any change int he rough idle and rpm movement to it.
4) Techron is a complete waste of time and money in a DI car. Stop wasting your money. I actually think the fuel cleaner could be part of the problem (two times my mechanic ran it for me as a "favor" and my car ran like shit for weeks). All it did was disturb deposits, and run them through a super-sensitive system. Just leave it alone. It won't even clean the injectors, which is the only reason you'd run Techron in the first place.
5) Intake system issues could also be a part of the problem. Our plastic manifolds are crappy, and can crack and be invisible. I've had 3 smoke tests identify 3 separate issues that dramatically improved my car's idle. Charge pipe crack, leaking inlet on the turbo (I'm starting a thread on that soon), and valve cover gasket breach. All were invisible until we smoke tested.

Bottom line, this engine is tuned tighter than a dolphin's ass, and it's likely not just one thing that can cause it to run a bit. This is primarily an issue of a German over engineered system. If one gnat's asshair is out of place, a driver that is tuned into their automobile will notice it. If a few are out of place, your blind, deaf aunt will notice.

Thanks to all contributing to this thread. We're lucky to have such an involved and thoughtful community.

AA

Totally agree with your analysis of techron, thanks for the post

[FamilyManTrackSedan]

Originally Posted by speculator

I decided to change all of the 6 injectors. Now after two cold starts everything seems to be ok. Engine is running very smooth -no shaking or rpm hunting occurs anymore. Actually, the engine runs perfectly!

However, the local BMW service wanted to change 4 coils at the price of 114€/piece, because according to them "4 coils is broken". I decided not to change them and maintain in the original plan and change the injectors first. Now the engine runs perfectly, what do you think I should do with the coils?

To my mind, if 4 coils are broken, the engine won't even start. Or at least, there must be some issues if 4 coils is broken? I don't want to change unbroken parts...

Thank you in advance for your answer.

I'm cool with people letting shops or dealers work on their car. But do some homework FFS. In this case, you didn't fall for what amounts to robbery. An ignition coil is approx $50 online and it takes approx 10 minutes to replace one. It requires about the same amount of skill as changing a lightbulb.

I don't know what's worse - a dealer charging that kind of markup for labor and materials, or a BMW owner of a car that asks something from you every 5k miles after 60k, pissing away their money to them on things like that, believing every word they say, and coming back the next week for the next thing. /rant

[skyotee]

Originally Posted by skyotee

Ugh, this thread --

Okay, so I am the latest victim of the rough idle. I have a 2012 335is with 35K mi. I have owned it since 27K, and have been running MHD for a few weeks.

Everything started out perfect, car ran perfectly, and even faster with MHD. I installed my Wagner FMIC, and went stage 1+, still running perfectly and no rough idle. UNTIL -- I blew my charge pipe a week later. I drove about 10 mi in limp mode with the blown charge pipe to get home (I know, probably not my best move).

Anyway, I put on a new ER charge pipe with Forge DV, and now I have the dreaded rough idle! Ideas?! My first thought after reading much of this thread -- clean the TMAP sensor. What should I use to clean it? Since the rough idle started after blowing the charge pipe, I am thinking of things that might have been affected by that -- Dirty TMAP? Could the throttle body have come loose? Maybe I fouled an injector or plug driving around with no intake filter?? Or someone in this thread mentioned a vacuum leak cause?

Any ideas on what order I should start troubleshooting this in? At 35K, I am also due for plugs which I was going to do anyway. But I did not have rough idle before the blown charge pipe. But could that have caused plug fouling anyway (running too rich somehow)??

I do have a CPO warranty... Should I just bring it in? Maybe someone knows of a good dealership for a car like mine, in the LA area.... (PM?)

Thanks for any input!

Still dealing with this. First I changed the plugs & cleaned the VANOS solenoids, no help. I took it to the dealer and they changed the coil packs & replaced my leaking valve cover gasket. Next, I cleaned the TMAP and throttle body. Still have the stumbling RPM/rough idle. Are there any adaptations I should reset, having done all this work? Any ideas on what to try next?

Probably need to go back to the dealer for the same issue and tell them they did not fix it, so maybe they will try harder this time. They basically started by saying they did not notice the rough idle, and then they said the coil packs were probably contaminated by oil from the leaking valve cover, and that was the cause of the idle problem... Which was kind of lame, since I pulled the coil packs when I did the plugs and there was no oil on them, just on cyl 3 plug.

[bartbes]

I have changed and cleaned everything mentioned here with no luck. People keep saying it first started doing it with new plugs, I switched to ngk gapped to 0.22, problem solved.

[skyotee]

So, the last page of this thread has one guy replacing all the injectors, and anothe trying NGK plugs, both fixing their issues. Maybe I will try the plugs first!!

Any other ideas?

Also, sorry for the newb question, but is it normal to find a bit of oil in the charge pipe?

[dgrbovic]

I have had the same issue (after 140k miles). Rough idle but no fault codes. They found that it was one ignition coil but they suggester replacing all 6 since they were already in there. Since mine is a SULEV vehicle in California, it turned out that the issue was covered so I didn't pay a dime . The car works like a charm now.

[ANMVQ]

So I read this whole thing hoping to find answer :/, I have this as well, lumpy idle( the car has came) my idle is ROCK solid tho at like 650(AT) I always let the car warm up for at least 5 mins before driving and the car everytime lurches forward for a few mins when idling forward and pressing the break, I've also noticed I get long cranks sometimes speeding low long it sits?
I'm waiting for CEL to take it to the dealer as I have a extended warranty. BTW car is a 2011 335XI with just about 61k on her and I've had this issue for about 5k miles

[Spyro235]

I've been battling this issue for the last few months, I just bought my car at 128k miles, now at 134k. I recently had to add a tiny bit of oil to hold me over until I get the chance to change it, and it ran absolutely perfectly for about a day and a half. I did the injectors a little while back, I had index 8, and now I have 6 new index 12's. I need to check my spark plugs to see how they look, and gap them, and possibly replace all of them. My MAF (or whatever bmw decided to call it) is responding perfectly and immediately to throttle changes when monitered in real time. I'm consulting my mechanic (Matt at ZNM) and he's helping me hunt this issue down, as I on't believe he's seen this problem before. For the record, I get really rough, oscillating idle on cold starts, and oscillating RPMs at a constant light throttle. For instance, if I hold the gas just enough to bring it up to 1000 RPM, it'll waver and stumble form 1200 down to 600rpm, but sometimes it'll fall down to 100-300 rpm. The car has stalled on me a total of three times, all when cold, because of this stumble. It's a real issue, and when it stumbles in 1st or second (or while clutching into either) it causes some VERY sudden, uncomfortable jerking. This is an issue I am hunting down and truly aim to fux, because after I fix it, I have to start saving for new turbos.

[Spyro235]

For the record, the car only threw a misfire code once. Otherwise, the engine light has never come on for this issue. If the issue is really that cylinder, I presume the plug will be in rough shape. I'll try a new plug, and then move to the coils.

[MrAC]

Originally Posted by muncie21

I have a slight misfire/rough idle on warm restart. This is with heater/AC off. Not enough of a miss to trigger a code or CEL, but noticeable none the less.

BTW, I have all new plugs and coils, still does it.

I know this post was old lol

But did you end up fixing that misfire of yours? If so, how did you fix it?

I have a similar problem.

[uhNexus]

If your car feels like it's vibrating when you're idling after coming to a stop, you might need to walnut blast it.

[uhNexus]

Originally Posted by ANMVQ

So I read this whole thing hoping to find answer :/, I have this as well, lumpy idle( the car has came) my idle is ROCK solid tho at like 650(AT) I always let the car warm up for at least 5 mins before driving and the car everytime lurches forward for a few mins when idling forward and pressing the break, I've also noticed I get long cranks sometimes speeding low long it sits?
I'm waiting for CEL to take it to the dealer as I have a extended warranty. BTW car is a 2011 335XI with just about 61k on her and I've had this issue for about 5k miles

You don't need to let the car warm up for more than 1 minute. It warms up faster if you drive it, and if you're not going WOT or going past 3500 RPMs, no damage will be done.

[muncie21]

Originally Posted by MrAC

I know this post was old lol

But did you end up fixing that misfire of yours? If so, how did you fix it?

I have a similar problem.

Car still does this occasionally, however not often or bad enough for me to look further into the cause. I suspect there's another injector (replaced one in Feb 2016) on the way out or it could be carbon buildup on the valves as I haven't done a walnut blast since I purchased the car.

Keep in mind I don't drive it much, I've put on maybe 5k miles in the past 12 months.

[MrAC]

Originally Posted by muncie21

Car still does this occasionally, however not often or bad enough for me to look further into the cause. I suspect there's another injector (replaced one in Feb 2016) on the way out or it could be carbon buildup on the valves as I haven't done a walnut blast since I purchased the car.

Keep in mind I don't drive it much, I've put on maybe 5k miles in the past 12 months.

Understood, I also replaced my plugs/coils and when car is warm, I rev it at idle, I notice misfires/shaking when the rev hits about 1kish. Does this happen to you as well?

Offer than that, I feel like the misfire during a warm startup is a bit better, but like you said, still noticeable.

Thanks