Rough Idle, stumbling rpms

r4dr · 05-18-2017, 01:20 PM

Keep in mind: a "rough idle" could be caused by many different things, and that is something to realize when you read through this thread and see how many different ways people fixed this generic issue.

Some of it is trial and error, but doing more detective work like logging the car might help pinpoint the issues.

Johnny335i · 09-16-2017, 11:54 PM

Hi all,
I've been having misfire issue with misfire in cylinder 1, 3 and random, so i changed all my plugs, coils, fuel injectors to index 12, intake vanos solenoid and had walnut blasting done 3000km ago. Since then I haven't got any misfire codes yet but i still feel a few misfire when I start the car after it has been sitting for a long period of time. Car will start normal, idle to normal and then I hear a misfire and revs up a bit from normal idle level but no misfire codes are thrown. Same as what everyone is experiencing in this thread.

Has anyone found the solution?

Please help,

Car - 2008 BMW 335i sedan with no modifications and has 134,000KM

335e92tx · 09-17-2017, 11:46 AM

got anyway to log data?

jwebb335xi · 09-17-2017, 06:34 PM

Quote:

Originally Posted by Johnny335i

Hi all,
I've been having misfire issue with misfire in cylinder 1, 3 and random, so i changed all my plugs, coils, fuel injectors to index 12, intake vanos solenoid and had walnut blasting done 3000km ago. Since then I haven't got any misfire codes yet but i still feel a few misfire when I start the car after it has been sitting for a long period of time. Car will start normal, idle to normal and then I hear a misfire and revs up a bit from normal idle level but no misfire codes are thrown. Same as what everyone is experiencing in this thread.

Has anyone found the solution?

Please help,

Car - 2008 BMW 335i sedan with no modifications and has 134,000KM

Without misfire codes, are you certain that's the issue? Perhaps your getting erratic fuel delivery related to 02 sensors?

Logging your car at idle MAY give you some clues...

dbensman1 · 10-12-2017, 03:21 PM

Well, first tons of thanks to AWD Addict for starting this thread. I spent 4 days and 18 clumps of hair sorting through all 17 pages +.

So, yeah, after exactly the same situation many of you described in detail, I figured mine out.

Flipping through the Bavarian Auto catalog is what got me into this whole mess in the first place. My just 47k 2010 335xi had absolutely no tuning or performance problems. The only mod on it is a K&N cold air intake. But seeing their ‘high performance’ ignition coils on sale, and having done them before on an e39, I pulled the trigger on coils and spark plus, just for giggles. It’s been a shit show since.

First, I checked all connections and re-tightened everything. Checked for any cracked hoses and vacuum leaks. Using an old (stock) ignition coil, I pulled each new ignition coil, in sequence, to check if I had any duds in the new batch. I removed and cleaned both the MAF and TMAP. What finally worked?

I re-installed the old sparkplugs. That was it. I cleaned them and simply swapped the OEM plugs back. Everything back to smooth, steady, silky idle.

The Bosch plugs I purchased were from Amazon. Guess I should have read the negative reviews more closely. I ensure you they were the correct spec. Maybe there are widespread fakes out there, or a huge batch of defective plugs that came off the line? I don’t know. Of course, it’s possible that the ignition system on these cars is so touchy, that new plugs simply jar the thing out of whack. Possible. What I DO know, however, is that I’m going to sell this car before the plugs die. Ugh.

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

335e92tx · 10-12-2017, 04:38 PM

Quote:

Originally Posted by dbensman1

Well, first tons of thanks to AWD Addict for starting this thread. I spent 4 days and 18 clumps of hair sorting through all 17 pages +.

So, yeah, after exactly the same situation many of you described in detail, I figured mine out.

Flipping through the Bavarian Auto catalog is what got me into this whole mess in the first place. My just 47k 2010 335xi had absolutely no tuning or performance problems. The only mod on it is a K&N cold air intake. But seeing their ‘high performance’ ignition coils on sale, and having done them before on an e39, I pulled the trigger on coils and spark plus, just for giggles. It’s been a shit show since.

First, I checked all connections and re-tightened everything. Checked for any cracked hoses and vacuum leaks. Using an old (stock) ignition coil, I pulled each new ignition coil, in sequence, to check if I had any duds in the new batch. I removed and cleaned both the MAF and TMAP. What finally worked?

I re-installed the old sparkplugs. That was it. I cleaned them and simply swapped the OEM plugs back. Everything back to smooth, steady, silky idle.

The Bosch plugs I purchased were from Amazon. Guess I should have read the negative reviews more closely. I ensure you they were the correct spec. Maybe there are widespread fakes out there, or a huge batch of defective plugs that came off the line? I don’t know. Of course, it’s possible that the ignition system on these cars is so touchy, that new plugs simply jar the thing out of whack. Possible. What I DO know, however, is that I’m going to sell this car before the plugs die. Ugh.

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

Well, dan ;-), sorry you had bad luck. There are blue ring and green ring bosch plugs. it looks like the one realoem shows for mine is a green. http://www.realoem.com/bmw/enUS/part...&q=12120037244

I got a set of blue rings in a bag and was gonna swap them out in the next few K. Iv bought at least 3 previous sets off of ebay (blues i think) with no prob. shrug..

funflyer63 · 11-21-2017, 10:58 PM

Hey all, I'm struggling with the high-load stumble issue and have been for about a year. Same old symptoms: missing and hesitating on the highway under load at 2000 rpm up. This happens at both part and full throttle.

I've done plugs and coils. Earlier this year, I did the walnut blast. I've run Techron. Nothing works particularly well.

So. the car's been at the dealer for a couple of weeks. I asked them to look at the problem. They found a fault on the low-pressure fuel sensor and replaced it. After doing a smoke test, they replaced one of the turbo dump valve assemblies. Got the car back and no joy. It still had the problem.

Brought it back to the dealer and took the shop foreman for a ride. He ended up over the next few days replacing all the injectors and HPFP. He pulled the O2 sensors and checked that the cats were not blocked. He pulled the intake manifold and verified the intake ports were clean. He swapped plugs and coils to check to see if anything followed the changes, but no problem was found.

I got the car back tonight and it, frankly, is worse than when I brought it to them. Talking to the foreman, he was at a loss. His next step would have been to replace the engine wiring harness, then the DME if the harness swap didn't work.

I've seen issues with the MOSFETs in the DME, but don't think they fail gradually. If they did, this could be the source of the problem, but I really doubt it. Has anyone seen a harness failure? If so, what fails?

The car has barely 90k miles on it and hasn't been abused. Any thoughts are appreciated.

MysticRob · 11-22-2017, 03:27 PM

Quote:

Originally Posted by funflyer63

I've done plugs and coils. Earlier this year, I did the walnut blast. I've run Techron. Nothing works particularly well.... ended up over the next few days replacing all the injectors and HPFP...I got the car back tonight and it, frankly, is worse than when I brought it to them. Talking to the foreman, he was at a loss. His next step would have been to replace the engine wiring harness, then the DME if the harness swap didn't work.

I've seen issues with the MOSFETs in the DME, but don't think they fail gradually. If they did, this could be the source of the problem, but I really doubt it. Has anyone seen a harness failure? If so, what fails?

The car has barely 90k miles on it and hasn't been abused. Any thoughts are appreciated.

DME doesn't sound plausible, nor does wiring harness. 7yrs old, 90k miles on it, could be anything but I'd still look at the most common fail points.

Multiple plugs and coils, new injectors, HPFP, etc. Usually it's one or more of those. Brand, gap, purchase location (ebay, Amazon, neighbor) etc, of those parts?
What codes are you pulling, if any, and what are you using to try to pull them?
Any mods?
How about vacuum lines?
Replaced with 3.5mm at any point?
Test the rest of the turbo system including solenoids, canisters, plastic fittings, wastegate actuators, etc.

xlr88r · 12-06-2017, 05:01 PM

Hi All,

I'm a newbie to this to forum and forums in general, but this has been a great resource so far. Just over a week ago I picked up an 06 330i with 72k on the clock and a total of 13 stamps in the book, but zero receipts. Naff all. It's wearing an AFE Intake of some sort and EBC brakes so this could have had a, erm, 'spirited' previous owner, but otherwise seems stock.

Anyway. I drove it back from the dealer, to and from work (a 130 mile round trip!) and the following morning it was misfiring like mad. Belled the dealer and got it booked in to a local garage to be looked at, as I wasn't dead comfortable doing 30 odd miles in it misfiring like it was. The diagnostics said the coil pack on 6 was dead. That was replaced along with the plugs too. Finally to the question... I can go on a bit!

The garage kept the old plugs and gave them to me, and this is what they look like. I went a bit Sherlock and called the garage that had done the last 3 services. The plugs were replaced at just over 54k in April 2016, so they're roughly 18 months and 18k miles old.

I honestly don't know: do these look about right, terrible, or really clean? Given some of the aftermarket bits attached to it, I'm hoping this kind of life from a set of plugs is OK, and not a sign that it's spent a part of its life being absolutely hammered about!

Erk! Beanie.

kickserve · 01-10-2018, 08:58 PM

well, here's my contribution:

my '12 e91 xdrive developed a rough idle with the bouncing rpm (600-700) and stuttering/jerking (without a SESL) and then came a noticeable stuttering/shaking when accelerating between an RPM of 1200-2000 (at which point the SESL came on). Took it to the dealer since I'm in my last few months of CPO. Cylinder 6 was the culprit and all 6 coils + plugs got replaced under warranty. Along with that, my SA recommended getting the fuel induction service (BG fuel induction + GDI intake service) to (paraphrasing here) clean out all the stuff that led to this notorious problem. From what I gather, I probably could have DIYd this... next time I guess. Fingers crossed that this does the trick.

(just noticed this was the N54 section- and not N52 (mine). sorry if this post is irrelevant. this was first thread I went through when my car was acting up so I thought I would chime in. thanks to AWD Addict and others for posting here.)

Spineless · 01-10-2018, 10:11 PM

My car has a recent history of throwing injector codes and a super rough morning idle. I recently purchased a nice diagnostic tool, Foxwell NT-510. After scanning and retrieving the codes, I cleared all of the codes. The peculiar thing is that since clearing the codes, my car has run better, not perfect, but better. The rough morning idle is gone, and it hasn’t thrown any injector codes since then. I do have to occasionally “reboot” the car in the morning still when it is stumbling, but not specifically misfiring.

Has anyone else seen this sort of behavior? Could it have been that the DME was trying to compensate for the active codes?

My new injectors were delivered today for this weekends installation.

335e92tx · 01-11-2018, 08:24 AM

Quote:

Originally Posted by xlr88r

Hi All,

I'm a newbie to this to forum and forums in general, but this has been a great resource so far. Just over a week ago I picked up an 06 330i with 72k on the clock and a total of 13 stamps in the book, but zero receipts. Naff all. It's wearing an AFE Intake of some sort and EBC brakes so this could have had a, erm, 'spirited' previous owner, but otherwise seems stock.

Anyway. I drove it back from the dealer, to and from work (a 130 mile round trip!) and the following morning it was misfiring like mad. Belled the dealer and got it booked in to a local garage to be looked at, as I wasn't dead comfortable doing 30 odd miles in it misfiring like it was. The diagnostics said the coil pack on 6 was dead. That was replaced along with the plugs too. Finally to the question... I can go on a bit!

The garage kept the old plugs and gave them to me, and this is what they look like. I went a bit Sherlock and called the garage that had done the last 3 services. The plugs were replaced at just over 54k in April 2016, so they're roughly 18 months and 18k miles old.

I honestly don't know: do these look about right, terrible, or really clean? Given some of the aftermarket bits attached to it, I'm hoping this kind of life from a set of plugs is OK, and not a sign that it's spent a part of its life being absolutely hammered about!

Erk! Beanie.

Only the one with the white around the ground electrode looks as it should.
Get a leakdown test done.
What is oil use like?

muncie21 · 01-19-2018, 09:44 AM

Quote:

Originally Posted by Spineless

After scanning and retrieving the codes, I cleared all of the codes. The peculiar thing is that since clearing the codes, my car has run better, not perfect, but better.

Interesting theory, I've had this happen a few times. Car is missing/throwing a code...plug in the laptop and clear the code and it runs perfectly for several days/weeks.

Not sure if the ignition cycling is the root cause or clearing the codes. Either way, it has happened several times in the past years.

Matthewricha · 01-26-2018, 05:16 PM

Thanks AWD Addict for your useful info in this thread!

Hi have a 2006 335i with 74k miles. I've owned it for 6 years, but have had this stumble idle for last 18months. More recently the stumble is worse when cold, but calms down a bit once warm, but still there and seems more prevalent when it's wet / raining outside. WOT and boost is ok, Stumbling is felt at partial throttle and idle.

I have had the following done:
New Turbos @ 35k
New Vanos Solenoids @ 47k
VGC + Boost PCV Pipe replaced @ 65k
6 New Injectors (Index -12) @ 66k
Two new Boost Solenoids @ 68k
Vacuum lines 3mm rubber @ 68k (except lines from Boost Solenoids to Wastesgates)
Wallnut blast + OFH Gasket @ 71k
External PCV fitted with Mishimoto Catch Can @ 72k
6 Spark Plugs @74k (NGK, gapped to 0.022 thou)
6 Bosch Coils @74k
Vanos solenoids cleaned @74k

New Plugs made a marked improvement in running, but hasn't solved the problem.

There are no codes and smooth running values are apparently ok. Local Indy can't find anything wrong. Apparently the Fuel pressues are fine. They also performed a smoke test and couldn't find any leaks. There isn't a Valve cover crack that I can see. There is a small oil leak from the VGC near the OFH. If this was an issue for the vacuum passages to the valves I would have thought it would have shown up in the smoke test.

Should I be looking at O2 sensors next? Maybe clean TPS sensors? I have no codes, so can these cause issues without codes? Think maybe blocking the head vacuum ports would eliminate some potential issues, but would be a big job.

Cese5 · 06-19-2018, 03:30 PM

So....after reading 17 pages of possible solutions I can say I've nothing to add and still have this problem (rough idle at start with occasional stall at warm stops). It first occurred in 2017 at 50K, I'm around 100K now. At 70K (January 2018) I did plugs, coils, valve cleaning, PCV replacement, idle throttle adjustment, valve cover replacement and every damned thing else the dealer could think of for 4.5K. Maintenance is regular and with BMW spec materials, no cutting corners. 40K of highway driving later (700 m weekly commute)it has returned. Ugh! My love affair with the car is ending......

Spyro235 · 06-21-2018, 01:02 PM

Quote:

Originally Posted by Cese5

So....after reading 17 pages of possible solutions I can say I've nothing to add and still have this problem (rough idle at start with occasional stall at warm stops). It first occurred in 2017 at 50K, I'm around 100K now. At 70K (January 2018) I did plugs, coils, valve cleaning, PCV replacement, idle throttle adjustment, valve cover replacement and every damned thing else the dealer could think of for 4.5K. Maintenance is regular and with BMW spec materials, no cutting corners. 40K of highway driving later (700 m weekly commute)it has returned. Ugh! My love affair with the car is ending......

Are you on MHD? Reset the Lambda adapts. Didn't see that your O2's were changed, that's the first place to start I would think. O2 adapts solved all of my woes, which you exactly described.

Spineless · 06-22-2018, 02:22 AM

The only things I didn’t see you mention are injectors or fuel pumps. Have either of those been done? Do you have any codes? Even without a SES light, the car may be throwing codes.

iseck1 · 06-28-2018, 11:01 AM

After weeks of troubleshooting my rough idle E93 N54 I managed to solve mine. Tried everything discussed on these threads including walnut blasting the intakes, coils, cleaning electrical connectors, etc. and nothing worked. As a last resort I decided to put back the old spark plugs and voila - car runs good as new much to my surprise. Here's what I learned through the process that I thought i'd share with the forum in case it can help others. I had a bit of a rough idle a few weeks ago for which I started with new plugs from Amazon. The plugs were new OEM BMW BOSCH 4 electrode plugs and were exactly the same part number as what was in the car - even the stamping on the side was exactly the same including the "made in germany" part. There was no reason to suspect any issues with these plugs. During the change I also added a catch can and replaced a spark plug heat shield tube on #3 cylinder which had what appeared to be corrosion on it i.e. crusty green deposits. What I later learned is that corrosion is linked to spark arcing through the coil insulator to ground through the spark plug heat shield. Not all BMW's use this heat shield but it appears to be common on Turbo cars - down side to them is that they provide a good ground very close to the coil stem which can allow the spark to jump out. Once it starts the insulator deteriorates and issue gets worse. The corrosion is ionized air on the aluminum sleeve. It also deposits on the coil stem so keep a watch for these and clean (or preferably replace) these coils as needed. I suspect this was the initial reason for my rough idle but by putting in new plugs I managed to move the problem and cause weeks of headaches trying to troubleshoot. Now back to the plugs - after close inspection of the new plugs the only physical difference appears to be the gapping of the 4 electrodes. One or two electrodes on the new plugs appear to be closer to the center pin than the old ones. Remember - these are factory gapped plugs and not intended to be re-gapped by the user. I figured the larger gaps was wear on my old plugs and decided not to address it on the new ones. After about 500Km of horrible idling and lots of troubleshooting I swapped back to the old plugs as a last resort. I examined the new ones and found the ones with the small gaps had burn marks only one side of the porcelain insulator. That a sign that three other electrodes were likely not firing. All that to say - I believe short of an internal issue with the new plug (i.e. manufacturing defect) the root cause is the smaller gap on some electrodes causing an insufficient spark for proper detonation especially on idle. That likely explains why the computer does not detect a fault and why certain conditions like load from the AC compressor or engine/ambient temperature vary the symptoms. Since switching back to the old plugs the car is running perfect. If I find some time I plan to pull the old plugs again and measure the gaps then regap the new plugs somehow to match and try them again. If that works then this will tell for certain the gap is the root cause and not a plug manufacturing defect. Another key lesson here is to pay close attention to the details and part conditions. You could replace all coils, plugs, injectors and hope for the best but in my case that would have addressed the arcing coil issue and not the faulty plug gap. I would have thrown out lots of good parts and money in the process and I hate doing that because you never get to actual root cause and you waste lots of money. If the rough idle returns, I would keep a close eye the coil stems and plug heatshields. If it happened to one, it's likely going to happen to one of the other 5 and it will leave a crusty deposit as a telltale sign. Will also need to be much more careful with spark plugs - I might try NGK's as I'm told some newer BMW's come with those from factory now. Check the gaps! Hope this helps in case you are dealing with the same issues.

go0gyy · 08-11-2018, 07:50 PM

Hi everyone. I am new to the forum and this is my first post so if something isn’t right, I apologize. I catch on quick tho. Recently purchased a 08 335xi. In 5k miles of me owning the car I have had to replace the radiator, pump, t stat, and al the inlets and outlets. Yes, I know. After they were replaced I’ve had a misfire in cylinder 5. Now when I bought the car I had the same issue due to a leaky injector, I took the injector out the same model n54 and swapped them, never did any coding just plug and play. Car ran like trash for a few days but then smoothed our to a whopping 21 mpg all day. After I had the cooling system replaced now my car won’t go past 4K rpm without hiccuping and misfiring. I changed the plug and coil in cylinder 5 aswell. Could this be a cause of not coding the injector ? Please help !! Thanks !

Mizkizaa · 08-11-2018, 08:50 PM

Quote:

Originally Posted by go0gyy

Hi everyone. I am new to the forum and this is my first post so if something isn’t right, I apologize. I catch on quick tho. Recently purchased a 08 335xi. In 5k miles of me owning the car I have had to replace the radiator, pump, t stat, and al the inlets and outlets. Yes, I know. After they were replaced I’ve had a misfire in cylinder 5. Now when I bought the car I had the same issue due to a leaky injector, I took the injector out the same model n54 and swapped them, never did any coding just plug and play. Car ran like trash for a few days but then smoothed our to a whopping 21 mpg all day. After I had the cooling system replaced now my car won’t go past 4K rpm without hiccuping and misfiring. I changed the plug and coil in cylinder 5 aswell. Could this be a cause of not coding the injector ? Please help !! Thanks !

You have to code the injectors. Otherwise the dme doesn’t know how much fuel it is injecting. If it doesn’t know how much fuel you could run too lean or too rich. Also by just throwing a random injector in you could be mixing index’s numbers that the dme doesn’t like. I would assume from the age of the car that the injectors have probably been replaced with the newer index numbers, but you should still check. I believe if they are index number 10-12 they are compatible with each other, but still have to be coded. If you mix the 10-12 with 1-9 your car will not run correctly. The index number is the last 2 numbers after the dash on the injector. I would first check to see if index numbers are compatible. If they are then it needs to be coded. Also if 1 injector failed and there’s around 100,000 miles on them, the others are probably on the way. Hope that helps.

go0gyy · 08-12-2018, 10:22 AM

Quote:

Originally Posted by Mizkizaa

You have to code the injectors. Otherwise the dme doesn’t know how much fuel it is injecting. If it doesn’t know how much fuel you could run too lean or too rich. Also by just throwing a random injector in you could be mixing index’s numbers that the dme doesn’t like. I would assume from the age of the car that the injectors have probably been replaced with the newer index numbers, but you should still check. I believe if they are index number 10-12 they are compatible with each other, but still have to be coded. If you mix the 10-12 with 1-9 your car will not run correctly. The index number is the last 2 numbers after the dash on the injector. I would first check to see if index numbers are compatible. If they are then it needs to be coded. Also if 1 injector failed and there’s around 100,000 miles on them, the others are probably on the way. Hope that helps.

It helps greatly, thanks. Makes me almost certain that it’s the injector causing the misfire. Of course I don’t have the cash at the moment to buy all 6 index 12s right now since I took the cooling system hit. Have you had any experience with you using a China index 12 from amazon for about a month until I can save to get some true 12s? Lastly, what damage can be done to the motor by driving the car like that? Thanks again.

Mizkizaa · 08-15-2018, 03:57 PM

Quote:

Originally Posted by go0gyy

It helps greatly, thanks. Makes me almost certain that it’s the injector causing the misfire. Of course I don’t have the cash at the moment to buy all 6 index 12s right now since I took the cooling system hit. Have you had any experience with you using a China index 12 from amazon for about a month until I can save to get some true 12s? Lastly, what damage can be done to the motor by driving the car like that? Thanks again.

Before buying all injectors I would first make sure your injector types are compatible. If they are I would code that 1 injector fist and see if that fixes your problem. It’s honestly pretty easy to code. You just need to get the cable ($20 or so on amazon) and have a laptop running windows and you can follow the instructions on how to setup the INPA software. Check out these links for some info. http://www.e90post.com/forums/showthread.php?t=918608
http://www.n54tech.com/forums/showthread.php?t=15140. I’m not sure about the Chinese injectors for these cars. I’ve seen multiple people saying they’re perfectly fine don’t waste you money on the “true” ones and others saying spend the extra money for no headaches using the cheap ones, there’s no consensus from what I can tell. I bought mine from FCP Euro and I think they were 160 a piece, a good middle ground with lifetime warranty. I obviously don’t want to say nothing is wrong with driving like that but typically if the car is running lean it will run hotter and be more susceptible to knocking. Since it’s 1 cylinder you shouldn’t be overheating and the knock system on these cars are pretty good so I would just drive it the least amount that you can, be easy on it and obviously don’t race it until you figure it out

05-18-2017, 01:20 PM	#353
r4dr First Lieutenant 173 Rep 393 Posts Drives: various BMWs Join Date: Oct 2015 Location: Seattle, WA iTrader: (0)	Keep in mind: a "rough idle" could be caused by many different things, and that is something to realize when you read through this thread and see how many different ways people fixed this generic issue. Some of it is trial and error, but doing more detective work like logging the car might help pinpoint the issues.
	Appreciate 0 Quote

09-16-2017, 11:54 PM	#354
Johnny335i Johnny 3 Rep 44 Posts Drives: 2008 BMW 335i Join Date: Jul 2008 Location: Toronto iTrader: (0)	Hi all, I've been having misfire issue with misfire in cylinder 1, 3 and random, so i changed all my plugs, coils, fuel injectors to index 12, intake vanos solenoid and had walnut blasting done 3000km ago. Since then I haven't got any misfire codes yet but i still feel a few misfire when I start the car after it has been sitting for a long period of time. Car will start normal, idle to normal and then I hear a misfire and revs up a bit from normal idle level but no misfire codes are thrown. Same as what everyone is experiencing in this thread. Has anyone found the solution? Please help, Car - 2008 BMW 335i sedan with no modifications and has 134,000KM
	Appreciate 0 Quote

09-17-2017, 11:46 AM	#355
335e92tx ahat 1073 Rep 2,592 Posts Drives: Was '07-335e92 - Now '13-335IS Join Date: Mar 2008 Location: Texas iTrader: (6)	got anyway to log data? __________________ '13 335IS N54 (1 of 373 LeMans Blue out of 3597 total production e92)- Grey interior (1 of 24 in LMB with any trans- 1 of 14 with DCT)-MODS -MFactory LSD/MHD-BQ custom Tune/ATM-IC/AFE Momentum GT Intake/Konis/Mfront&HeimJoint Rear rods&arms/Brembos. https://photos.app.goo.gl/Lo6aHZRo7XqtPkhL8
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10-12-2017, 03:21 PM	#357
dbensman1 Registered 0 Rep 1 Posts Drives: 2010 335i Auto AWD Join Date: Oct 2017 Location: Minneapolis, MN iTrader: (0)	Problem solved -- Bum Bosch plugs Well, first tons of thanks to AWD Addict for starting this thread. I spent 4 days and 18 clumps of hair sorting through all 17 pages +. So, yeah, after exactly the same situation many of you described in detail, I figured mine out. Flipping through the Bavarian Auto catalog is what got me into this whole mess in the first place. My just 47k 2010 335xi had absolutely no tuning or performance problems. The only mod on it is a K&N cold air intake. But seeing their ‘high performance’ ignition coils on sale, and having done them before on an e39, I pulled the trigger on coils and spark plus, just for giggles. It’s been a shit show since. First, I checked all connections and re-tightened everything. Checked for any cracked hoses and vacuum leaks. Using an old (stock) ignition coil, I pulled each new ignition coil, in sequence, to check if I had any duds in the new batch. I removed and cleaned both the MAF and TMAP. What finally worked? I re-installed the old sparkplugs. That was it. I cleaned them and simply swapped the OEM plugs back. Everything back to smooth, steady, silky idle. The Bosch plugs I purchased were from Amazon. Guess I should have read the negative reviews more closely. I ensure you they were the correct spec. Maybe there are widespread fakes out there, or a huge batch of defective plugs that came off the line? I don’t know. Of course, it’s possible that the ignition system on these cars is so touchy, that new plugs simply jar the thing out of whack. Possible. What I DO know, however, is that I’m going to sell this car before the plugs die. Ugh. https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1
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11-21-2017, 10:58 PM	#359
funflyer63 Registered 0 Rep 1 Posts Drives: 2010 E92 M-package Join Date: Jun 2014 Location: Northern California iTrader: (0)	Hey all, I'm struggling with the high-load stumble issue and have been for about a year. Same old symptoms: missing and hesitating on the highway under load at 2000 rpm up. This happens at both part and full throttle. I've done plugs and coils. Earlier this year, I did the walnut blast. I've run Techron. Nothing works particularly well. So. the car's been at the dealer for a couple of weeks. I asked them to look at the problem. They found a fault on the low-pressure fuel sensor and replaced it. After doing a smoke test, they replaced one of the turbo dump valve assemblies. Got the car back and no joy. It still had the problem. Brought it back to the dealer and took the shop foreman for a ride. He ended up over the next few days replacing all the injectors and HPFP. He pulled the O2 sensors and checked that the cats were not blocked. He pulled the intake manifold and verified the intake ports were clean. He swapped plugs and coils to check to see if anything followed the changes, but no problem was found. I got the car back tonight and it, frankly, is worse than when I brought it to them. Talking to the foreman, he was at a loss. His next step would have been to replace the engine wiring harness, then the DME if the harness swap didn't work. I've seen issues with the MOSFETs in the DME, but don't think they fail gradually. If they did, this could be the source of the problem, but I really doubt it. Has anyone seen a harness failure? If so, what fails? The car has barely 90k miles on it and hasn't been abused. Any thoughts are appreciated.
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12-06-2017, 05:01 PM	#361
xlr88r Second Lieutenant 331 Rep 205 Posts Drives: 2006 E90 & E91 330i M Sport Join Date: Nov 2017 Location: Leicester iTrader: (0)	Hi All, I'm a newbie to this to forum and forums in general, but this has been a great resource so far. Just over a week ago I picked up an 06 330i with 72k on the clock and a total of 13 stamps in the book, but zero receipts. Naff all. It's wearing an AFE Intake of some sort and EBC brakes so this could have had a, erm, 'spirited' previous owner, but otherwise seems stock. Anyway. I drove it back from the dealer, to and from work (a 130 mile round trip!) and the following morning it was misfiring like mad. Belled the dealer and got it booked in to a local garage to be looked at, as I wasn't dead comfortable doing 30 odd miles in it misfiring like it was. The diagnostics said the coil pack on 6 was dead. That was replaced along with the plugs too. Finally to the question... I can go on a bit! The garage kept the old plugs and gave them to me, and this is what they look like. I went a bit Sherlock and called the garage that had done the last 3 services. The plugs were replaced at just over 54k in April 2016, so they're roughly 18 months and 18k miles old. I honestly don't know: do these look about right, terrible, or really clean? Given some of the aftermarket bits attached to it, I'm hoping this kind of life from a set of plugs is OK, and not a sign that it's spent a part of its life being absolutely hammered about! Erk! Beanie.
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01-10-2018, 08:58 PM	#362
kickserve Enlisted Member 30 Rep 39 Posts Drives: 2012 e91 xdrive Join Date: Oct 2017 Location: Michigan iTrader: (1)	well, here's my contribution: my '12 e91 xdrive developed a rough idle with the bouncing rpm (600-700) and stuttering/jerking (without a SESL) and then came a noticeable stuttering/shaking when accelerating between an RPM of 1200-2000 (at which point the SESL came on). Took it to the dealer since I'm in my last few months of CPO. Cylinder 6 was the culprit and all 6 coils + plugs got replaced under warranty. Along with that, my SA recommended getting the fuel induction service (BG fuel induction + GDI intake service) to (paraphrasing here) clean out all the stuff that led to this notorious problem. From what I gather, I probably could have DIYd this... next time I guess. Fingers crossed that this does the trick. (just noticed this was the N54 section- and not N52 (mine). sorry if this post is irrelevant. this was first thread I went through when my car was acting up so I thought I would chime in. thanks to AWD Addict and others for posting here.) Last edited by kickserve; 01-10-2018 at 09:29 PM..
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01-10-2018, 10:11 PM	#363
Spineless New Member 0 Rep 16 Posts Drives: 2018 540i, 2018 6GT, 2009 335i Join Date: Jul 2014 Location: Bellevue, WA, USA iTrader: (0)	Something peculiar that I noticed... My car has a recent history of throwing injector codes and a super rough morning idle. I recently purchased a nice diagnostic tool, Foxwell NT-510. After scanning and retrieving the codes, I cleared all of the codes. The peculiar thing is that since clearing the codes, my car has run better, not perfect, but better. The rough morning idle is gone, and it hasn’t thrown any injector codes since then. I do have to occasionally “reboot” the car in the morning still when it is stumbling, but not specifically misfiring. Has anyone else seen this sort of behavior? Could it have been that the DME was trying to compensate for the active codes? My new injectors were delivered today for this weekends installation.
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01-26-2018, 05:16 PM	#366
Matthewricha Private First Class 84 Rep 161 Posts Drives: M235i Join Date: Dec 2013 Location: Hampshire iTrader: (0)	Thanks AWD Addict for your useful info in this thread! Hi have a 2006 335i with 74k miles. I've owned it for 6 years, but have had this stumble idle for last 18months. More recently the stumble is worse when cold, but calms down a bit once warm, but still there and seems more prevalent when it's wet / raining outside. WOT and boost is ok, Stumbling is felt at partial throttle and idle. I have had the following done: New Turbos @ 35k New Vanos Solenoids @ 47k VGC + Boost PCV Pipe replaced @ 65k 6 New Injectors (Index -12) @ 66k Two new Boost Solenoids @ 68k Vacuum lines 3mm rubber @ 68k (except lines from Boost Solenoids to Wastesgates) Wallnut blast + OFH Gasket @ 71k External PCV fitted with Mishimoto Catch Can @ 72k 6 Spark Plugs @74k (NGK, gapped to 0.022 thou) 6 Bosch Coils @74k Vanos solenoids cleaned @74k New Plugs made a marked improvement in running, but hasn't solved the problem. There are no codes and smooth running values are apparently ok. Local Indy can't find anything wrong. Apparently the Fuel pressues are fine. They also performed a smoke test and couldn't find any leaks. There isn't a Valve cover crack that I can see. There is a small oil leak from the VGC near the OFH. If this was an issue for the vacuum passages to the valves I would have thought it would have shown up in the smoke test. Should I be looking at O2 sensors next? Maybe clean TPS sensors? I have no codes, so can these cause issues without codes? Think maybe blocking the head vacuum ports would eliminate some potential issues, but would be a big job.
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06-19-2018, 03:30 PM	#367
Cese5 Registered 0 Rep 1 Posts Drives: 2007 328i Join Date: Jun 2018 Location: Northern VA iTrader: (0)	Old post, same problem So....after reading 17 pages of possible solutions I can say I've nothing to add and still have this problem (rough idle at start with occasional stall at warm stops). It first occurred in 2017 at 50K, I'm around 100K now. At 70K (January 2018) I did plugs, coils, valve cleaning, PCV replacement, idle throttle adjustment, valve cover replacement and every damned thing else the dealer could think of for 4.5K. Maintenance is regular and with BMW spec materials, no cutting corners. 40K of highway driving later (700 m weekly commute)it has returned. Ugh! My love affair with the car is ending......
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06-22-2018, 02:22 AM	#369
Spineless New Member 0 Rep 16 Posts Drives: 2018 540i, 2018 6GT, 2009 335i Join Date: Jul 2014 Location: Bellevue, WA, USA iTrader: (0)	The only things I didn’t see you mention are injectors or fuel pumps. Have either of those been done? Do you have any codes? Even without a SES light, the car may be throwing codes.
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06-28-2018, 11:01 AM	#370
iseck1 Registered 2 Rep 4 Posts Drives: 2007 E93 Join Date: Jun 2018 Location: Toronto Canada iTrader: (0)	N54 Rough Idle - fixed mine After weeks of troubleshooting my rough idle E93 N54 I managed to solve mine. Tried everything discussed on these threads including walnut blasting the intakes, coils, cleaning electrical connectors, etc. and nothing worked. As a last resort I decided to put back the old spark plugs and voila - car runs good as new much to my surprise. Here's what I learned through the process that I thought i'd share with the forum in case it can help others. I had a bit of a rough idle a few weeks ago for which I started with new plugs from Amazon. The plugs were new OEM BMW BOSCH 4 electrode plugs and were exactly the same part number as what was in the car - even the stamping on the side was exactly the same including the "made in germany" part. There was no reason to suspect any issues with these plugs. During the change I also added a catch can and replaced a spark plug heat shield tube on #3 cylinder which had what appeared to be corrosion on it i.e. crusty green deposits. What I later learned is that corrosion is linked to spark arcing through the coil insulator to ground through the spark plug heat shield. Not all BMW's use this heat shield but it appears to be common on Turbo cars - down side to them is that they provide a good ground very close to the coil stem which can allow the spark to jump out. Once it starts the insulator deteriorates and issue gets worse. The corrosion is ionized air on the aluminum sleeve. It also deposits on the coil stem so keep a watch for these and clean (or preferably replace) these coils as needed. I suspect this was the initial reason for my rough idle but by putting in new plugs I managed to move the problem and cause weeks of headaches trying to troubleshoot. Now back to the plugs - after close inspection of the new plugs the only physical difference appears to be the gapping of the 4 electrodes. One or two electrodes on the new plugs appear to be closer to the center pin than the old ones. Remember - these are factory gapped plugs and not intended to be re-gapped by the user. I figured the larger gaps was wear on my old plugs and decided not to address it on the new ones. After about 500Km of horrible idling and lots of troubleshooting I swapped back to the old plugs as a last resort. I examined the new ones and found the ones with the small gaps had burn marks only one side of the porcelain insulator. That a sign that three other electrodes were likely not firing. All that to say - I believe short of an internal issue with the new plug (i.e. manufacturing defect) the root cause is the smaller gap on some electrodes causing an insufficient spark for proper detonation especially on idle. That likely explains why the computer does not detect a fault and why certain conditions like load from the AC compressor or engine/ambient temperature vary the symptoms. Since switching back to the old plugs the car is running perfect. If I find some time I plan to pull the old plugs again and measure the gaps then regap the new plugs somehow to match and try them again. If that works then this will tell for certain the gap is the root cause and not a plug manufacturing defect. Another key lesson here is to pay close attention to the details and part conditions. You could replace all coils, plugs, injectors and hope for the best but in my case that would have addressed the arcing coil issue and not the faulty plug gap. I would have thrown out lots of good parts and money in the process and I hate doing that because you never get to actual root cause and you waste lots of money. If the rough idle returns, I would keep a close eye the coil stems and plug heatshields. If it happened to one, it's likely going to happen to one of the other 5 and it will leave a crusty deposit as a telltale sign. Will also need to be much more careful with spark plugs - I might try NGK's as I'm told some newer BMW's come with those from factory now. Check the gaps! Hope this helps in case you are dealing with the same issues.
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08-11-2018, 07:50 PM	#371
go0gyy Registered 0 Rep 2 Posts Drives: 2008 335xi Join Date: Aug 2018 Location: Northern NJ iTrader: (0)	Misfire in cylinder5 due to non coded injector? Hi everyone. I am new to the forum and this is my first post so if something isn’t right, I apologize. I catch on quick tho. Recently purchased a 08 335xi. In 5k miles of me owning the car I have had to replace the radiator, pump, t stat, and al the inlets and outlets. Yes, I know. After they were replaced I’ve had a misfire in cylinder 5. Now when I bought the car I had the same issue due to a leaky injector, I took the injector out the same model n54 and swapped them, never did any coding just plug and play. Car ran like trash for a few days but then smoothed our to a whopping 21 mpg all day. After I had the cooling system replaced now my car won’t go past 4K rpm without hiccuping and misfiring. I changed the plug and coil in cylinder 5 aswell. Could this be a cause of not coding the injector ? Please help !! Thanks !
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