[virtual_law]

Hello folks,

I have a 2007 335i e93 cabrio auto RHD at 50k miles.

I pulled the coils and plugs yesterday to inspect them cause low rpm driving was a bit jerky, idling not as smooth as I've come to expect from bmw inline sixes, and there's a slight surge/stumble when shifting up on partial throttle. Other than that, its got great smooth power throughout the rev range and no boost leaks or codes. The last job on it was a DME change.

My coils are relatively new, changed to Eldors less than 2000 kms ago.

Cylinder 1 and Cylinder 4 came out looking like they'd been on the wrong end of a shotgun, cylinder 4 particularly.

I also looked into the cylinder 4 well, and noticed the chrome sleeve that the coil sits in is missing. It seems that the last workshop lost it as I remember seeing it in there when I installed the Eldor coils. It is present on all other cylinders.

Cleaned spark plugs also, they were quite sooty and oily. Picture after cleaning is attached, arranged from Left to Right, cylinder 6 to 1.

What could this mean? Bad plugs, bad coil? Missing chrome sleeve a factor?

[Vitalauto]

Did oil get on the coils? Maybe those spots are from arcing, as the coil with the corresponding plug looks like it is not firing right. I need to do some post to pm turbid, sorry if my info is no good.

[virtual_law]

Originally Posted by Vitalauto

Did oil get on the coils? Maybe those spots are from arcing, as the coil with the corresponding plug looks like it is not firing right. I need to do some post to pm turbid, sorry if my info is no good.

No oil on the coils. I applied some die-electric grease on the ceramic part of the plug and over all these spots on the coil also. It didn't really make a difference to behavior though (the car sputters on first cold start with a misfire type feeling, then cycling the engine on and off it smoothens out). I am getting very low fuel pressure readings though (24 psi on cold idle), so I'll address that and pull the coils again to inspect.

The arching feels pretty severe on this cylinder though, do you reckon it has anything to do with the missing chrome sleeve?

[thatllbe2000bucks]

Great car you got there I have the same spec except it’s a LHD 😎

How many km on your spark plugs they look a bit dirty. Replace the tube seal. You can’t ask us to comment on the arching with a tube seal missing. Check your valve cover and valve cover gasket for leaks and replace your spark plugs if you still get stumbles. If they have never been changed do it regardless. Do you have any fuel injector problems? Maybe them being mismatched or leaking? Any codes?

[virtual_law]

Originally Posted by thatllbe2000bucks

Great car you got there I have the same spec except it’s a LHD ��

How many km on your spark plugs they look a bit dirty. Replace the tube seal. You can’t ask us to comment on the arching with a tube seal missing. Check your valve cover and valve cover gasket for leaks and replace your spark plugs if you still get stumbles. If they have never been changed do it regardless. Do you have any fuel injector problems? Maybe them being mismatched or leaking? Any codes?

Thanks! She's great when she works, which is usually a few weeks in between problems.

I did a few things to address the above issues. I replaced the tube seal with a bmw part from ECS. Put everything back together. It started up with a longer crank than usual. Idled a little rough, and feels like its misfiring but no codes. When I start driving, it smoothens out except at really low speeds, when its a little stumbly. As the car warms up, it smoothens out considerably, but its not 100% smooth. I can feel the hesitation and stumble at idle pretty regularly still. This condition is virtually the same as before the tube seal install. I have also replaced the low pressure fuel pump, and my idle pressure is back up to 5000 hpa i.e 72 psi.

I've been playing around with ISTA a lot. I've noticed that when I reset adaptations, it runs a little better for the first day or two.

I also did a WOT run after warming up, and it threw an exhaust Vanos code. I cleaned the exhaust Vanos carefully, lots of dirt around that area, tried my best not to introduce any dirt into the Vanos hole and into the engine. Cleared codes. It hasn't come back since a few days.

Afterwards, I diagnosed further with Ista and inspected injector values. The values were all over the place. I had to recode the injector flow values into the DME cause it showed very odd values to what was written on the injectors. My injectors are quite a mismatch also, from cylinders 1-6, I have index 7, 12, 7, 7, 10, 7. Oh well, I recoded and let the DME sleep over night. Next day, it again started with longer crank and feels like it's in exactly the same state hesitation wise.

My sparkplugs are about 6-8 months old, car has only done about 4000 miles on them.

Thinking I should replace them again because they look sooty, which of course points to leaky injectors. Really don't feel like dropping $2500 on index 12s.

What else can I do to ensure everything else is right?

[thatllbe2000bucks]

Originally Posted by virtual_law

Thanks! She's great when she works, which is usually a few weeks in between problems.

I did a few things to address the above issues. I replaced the tube seal with a bmw part from ECS. Put everything back together. It started up with a longer crank than usual. Idled a little rough, and feels like its misfiring but no codes. When I start driving, it smoothens out except at really low speeds, when its a little stumbly. As the car warms up, it smoothens out considerably, but its not 100% smooth. I can feel the hesitation and stumble at idle pretty regularly still. This condition is virtually the same as before the tube seal install. I have also replaced the low pressure fuel pump, and my idle pressure is back up to 5000 hpa i.e 72 psi.

I've been playing around with ISTA a lot. I've noticed that when I reset adaptations, it runs a little better for the first day or two.

I also did a WOT run after warming up, and it threw an exhaust Vanos code. I cleaned the exhaust Vanos carefully, lots of dirt around that area, tried my best not to introduce any dirt into the Vanos hole and into the engine. Cleared codes. It hasn't come back since a few days.

Afterwards, I diagnosed further with Ista and inspected injector values. The values were all over the place. I had to recode the injector flow values into the DME cause it showed very odd values to what was written on the injectors. My injectors are quite a mismatch also, from cylinders 1-6, I have index 7, 12, 7, 7, 10, 7. Oh well, I recoded and let the DME sleep over night. Next day, it again started with longer crank and feels like it's in exactly the same state hesitation wise.

My sparkplugs are about 6-8 months old, car has only done about 4000 miles on them.

Thinking I should replace them again because they look sooty, which of course points to leaky injectors. Really don't feel like dropping $2500 on index 12s.

What else can I do to ensure everything else is right?

Did you fix the issue? Your injectors are all over the place that’s most likely the problem here. Call your dealer maybe you are eligible for the free injector recall.

[aemdgt]

Hi there, I know this post is old, but just in case you’re still on the forum I wanted to check if you got a resolution. I have exact same issue with new Eldor coils (3 of them pitting) on an N54. I don’t believe it is cylinder specific as I initially moved the worst coil (cyl 4) to cyl 3. The old cyl 4 coil seems to have kept pitting while in cyl 3, the good one from cyl 3 that I moved to cyl 4 has no marks on it after ~1,000k’s.

Cheers