[ny330xi]

BACKGROUND:

So, I started a thread last week on an intermittent stumble I had at idle that didn't throw any codes for months. Eventually, it began to stumble more and then badly (even past idle) and threw a code for misfire in #6.

I started by replacing the coil. That didn't fix the issue.

So, I replaced plug #6 - didn't have time to do them all that night. That helped, but I still had the intermittent stumble where it might stumble once or twice every few times I stopped and dropped to idle.

I replaced all the plugs last weekend. It was great for a day or two. Now it's back to an occasional stumble when at idle.

Original thread:

http://www.e90post.com/forums/showthread.php?t=1080477

QUESTION:

What's my next step? Try replacing all the coils?

It seems like it must be an ignition issue, since changing the plugs made a difference, even if it didn't solve the issue.

If it were an injector issue or a vacuum issue - rather than ignition - is there any reason the stumble would have gotten better by changing out the plugs?

UPDATE

The thing went off the F@*ing rails today. Got about a mile from my house when it started fully misfiring, SES came on, pulled the codes:

Fehler: Failure detection cyl.7 / Misfire cyl. 5 / Short circuit to ground intake
Code: 29D1
Fehler: Misfire at low tank capacity / To misfire at low fuel level / Inlet air temperature is too low / Verbrennungsaussetzer bei niedrigen Kraftstoff-Fuellstand / Misfire detection with low fuel level
Code: 29D9
Fehler: Failure detection cyl.11 / Intake air temperature sensor / Misfire cyl. 6 / Lambda probe before catalyst pump current line
Code: 29D2
Fehler: Failure detection checksum / Misfire detection error summation / Intake air temperature sensor temperature is too high / Central control timeout
Code: 29CC

Update 2

Chased down a bad coil in #5 by swapping coils and checking misfire code. The bad stumble is gone, the intermittent stumble is back.

Looks like at the least there is more than one bad coil. And who knows what else. Will change the rest of the coils this weekend.

Update 3

Changed coils last Saturday morning, no stumbles at all since. At the moment, I'm tempted to say the problem seems to have been resolved.

[mike3000fl]

when it stumbled again, did it throw another code?

[MORTON]

When was the last time you changed the plugs and coils? How many miles are on your car?

You probably do need to go ahead and change the rest of your coil packs if they've never been changed. This may not fix the problem but it needs to be done regardless. What brand plugs and coil pack did you use? Did you check your gaps on the plugs?

[MORTON]

After replacing the rest of the coil packs, if the problem still persists I personally would go straight to the VANOS solenoids.. From there I'd go to the coolant temp sensor.. Before you do any of that though check for codes first. VANOS solenoids have been known to not throw faults before..

[TheTal0n]

Id buy a coil or two, only twenty bucks on amazon. try swapping them out. And you can switch the vanos solenoids with each other. that works sometimes. clean them off too.

http://www.bmwfanatics.co.za/showthread.php?tid=37935

http://www.pelicanparts.com/BMW/tech..._Replacing.htm

[ny330xi]

Originally Posted by mike3000fl

when it stumbled again, did it throw another code?

No, it only threw the code once, when the stumble got really bad. I cleared it, changed #6 plug, and it didn't come back.

Originally Posted by MORTON

When was the last time you changed the plugs and coils? How many miles are on your car?

You probably do need to go ahead and change the rest of your coil packs if they've never been changed. This may not fix the problem but it needs to be done regardless. What brand plugs and coil pack did you use? Did you check your gaps on the plugs?

Plugs and coils are original as far as I can tell based on service records and observation. The plugs are OEM NGK, gaps are spec. The car as 54K miles.

Originally Posted by TheTal0n

Id buy a coil or two, only twenty bucks on amazon. try swapping them out. And you can switch the vanos solenoids with each other. that works sometimes. clean them off too.

http://www.bmwfanatics.co.za/showthread.php?tid=37935

http://www.pelicanparts.com/BMW/tech..._Replacing.htm

I think I'm going to try the VANOS tomorrow AM, easy and free - might as well - though I'm not sure a VANOS problem would show as a misfire code.

[PichaDis11]

What are you using to pull codes?? Reason I ask is that it will be better to use a BMW scan tool rather than a generic one.

Vanos can sure be an issue and there are codes for them when it happens. That's actually how I replaced both.

[Agentphish]

my stumbling was 2 leaking fuel injectors.

[ny330xi]

Originally Posted by PichaDis11

What are you using to pull codes?? Reason I ask is that it will be better to use a BMW scan tool rather than a generic one.

Vanos can sure be an issue and there are codes for them when it happens. That's actually how I replaced both.

Using BMWhat...no VANOS codes, but it's easy, so I'll clean the solenoids anyway.

Originally Posted by Agentphish

my stumbling was 2 leaking fuel injectors.

Interesting. What codes were you seeing?

[ny330xi]

The thing went off the F@*ing rails today. Got about a mile from my house when it started fully misfiring, SES came on, pulled the codes:

Fehler: Failure detection cyl.7 / Misfire cyl. 5 / Short circuit to ground intake
Code: 29D1
Fehler: Misfire at low tank capacity / To misfire at low fuel level / Inlet air temperature is too low / Verbrennungsaussetzer bei niedrigen Kraftstoff-Fuellstand / Misfire detection with low fuel level
Code: 29D9
Fehler: Failure detection cyl.11 / Intake air temperature sensor / Misfire cyl. 6 / Lambda probe before catalyst pump current line
Code: 29D2
Fehler: Failure detection checksum / Misfire detection error summation / Intake air temperature sensor temperature is too high / Central control timeout
Code: 29CC



So, now I'm seeing multiple misfires. WTF?

Cleared the codes, took it around the block, and just the cylinder 5 code came back.

[Morpheus]

Try replacing or cleaning the tmap sensor. It's easy to get to and cheap to replace.

[ny330xi]

Still chasing this thing around:

Yesterday, since now it would pop an SES immediately on startup, I tried swapping coils to see if the code followed the #5 coil. It did. So, I swapped out the #5 and that stopped the severe misfire. The #5 coil apparently died.

However, it's gone back to an intermittent miss. A couple stumbles fairly consistently when at idle. I ordered more coils. I'll change them this weekend and check the plug gaps again.

I'm not sure what would make more than one coil go bad at once, but it seems there's another underlying issue.

Will update again after this weekend.

[mike3000fl]

Originally Posted by ny330xi

I'm not sure what would make more than one coil go bad at once, but it seems there's another underlying issue.

hi,

it's an 06, you are due

also curious... did you buy oem plugs? did you personally gap them?

[ny330xi]

Originally Posted by mike3000fl

hi,

it's an 06, you are due

also curious... did you buy oem plugs? did you personally gap them?

It's an 06, but I've only got 54K on the clock.

I did buy OEM plugs, NGK iridium, the current part revision #; they were pre-gapped. I checked a couple, they were fine. I'm going to take them all out and check again.

[mike3000fl]

If the gap is too great, the coils are overworking trying to create that spark, can lead to premature coil failure. On my car I had 1 coil go out, then another a month later, then one more shortly after that. In the end i said fuckit and just replaced them all instead of doing them one at a time. Turns out the electrodes on my plugs was pretty much gone, so the coils were probably having a hard time delivering a full spark.

[TheTal0n]

checkin back in on this, have you figured it out?
I actually had another coil go out yesterday, I have a 06 330i too haha. They are the original at 84k.

[ny330xi]

Originally Posted by mike3000fl

If the gap is too great, the coils are overworking trying to create that spark, can lead to premature coil failure. On my car I had 1 coil go out, then another a month later, then one more shortly after that. In the end i said fuckit and just replaced them all instead of doing them one at a time. Turns out the electrodes on my plugs was pretty much gone, so the coils were probably having a hard time delivering a full spark.

Yeah, that makes sense; that's why I'm going to re-check the gaps on Saturday morning when I have the time.

Originally Posted by TheTal0n

checkin back in on this, have you figured it out?
I actually had another coil go out yesterday, I have a 06 330i too haha. They are the original at 84k.

You're reading this in real time. Still working on it.

[pqsteve]

I had a coil go bad at 34K on my '11.

[ny330xi]

UPDATE 3

Last Saurday, I went in checked all the plug gaps, no issues, changed out coils 5 and 6 with OEM Bosch parts - the two cylinders which had associated codes. Since, I've had no stumbles at all. Fingers crossed.

As a side note, I decided not to replace all the coils for purposes of isolating the issue. I'll replace the rest after a couple thousand miles if there are no further issues.