[850CSi]

Hi all,

Car: 2006 325i, 170k miles. Manual transmission.

Problem: vibration and roughness generally. No relevant codes.

More specifically...

At idle -- the car holds a nice consistent rpm but I feel a regular vibration throughout the car. This got better, but did not resolve completely, after I recently swapped my engine mounts.

In neutral and revving engine at pretty much anything above idle -- vibration becomes less defined but the car generally still feels a little rougher than normal.

Under load/acceleration -- very significant shuddering and vibration of the entire car, especially in 1st and 2nd gears, and especially around 2-3k RPM.

These vibrations, particularly under 1st/2nd gear acceleration, have been present for a long while but were far less noticeable. The vibration at idle is a more recent development.

***

I know there are a number of possible sources so hoping to narrow things down.

My crank pulley/harmonic balancer looks like it's seen better days, but I'm not sure that could be the main contributor.

Anyone have any ideas? DMF? My clutch doesn't seem to be slipping, though I think I remember having felt some judder [I think mostly from a cold start] in the past, but not sure.

Any help is much appreciated!


---------------------------
EDIT: SOLVED. Read the thread for progression but basically I was probably dealing with a number of issues. Perhaps most prominently, a dual-mass flywheel that had a big hole in it and a driveshaft with a bad center support bearing and a sticky u-joint.
I have posted some info on the driveshaft swap further down.
I have more detailed posts in other threads about the flywheel.

[W37V]

I am betting it's DMF.

[velorider562]

I just discovered sheared bolts on the passenger engine mount bracket. I assume that would have been discovered when the mount was replaced. Replacing those improved cabin vibration.

[850CSi]

Originally Posted by velorider562

I just discovered sheared bolts on the passenger engine mount bracket. I assume that would have been discovered when the mount was replaced. Replacing those improved cabin vibration.

That's actually what I initially thought it was, having seen reports of that on here, but everything looked fine to me when I swapped the mounts.

[juld0zer]

misfire without code? Try reseating the coils

[850CSi]

Originally Posted by juld0zer

misfire without code? Try reseating the coils

Well that's the thing -- I have a lumpy idle and heavy vibration when accelerating (but smoother in both cases at higher RPM), so I don't think it's actually a misfire.

[juld0zer]

Any fault codes in the DME? eg. Vanos?
Oil in the eccentric shaft sensor connector?
Where do you feel the vibration comes from? Eg. front/middle/rear of car? Is it reproduceable with the handbrake up and wheels chocked with an assistant observing in the engine bay or a 4 post hoist?

[JonOhh]

My 330i has a bit of vibration at idle, but is smooth under any other circumstance.

Are the spark plugs due for a change? Does it seem like the engine itself is not producing power smoothly (misfire, and so on) , or that its coming from somewhere else?

[850CSi]

Originally Posted by juld0zer

Any fault codes in the DME? eg. Vanos?
Oil in the eccentric shaft sensor connector?
Where do you feel the vibration comes from? Eg. front/middle/rear of car? Is it reproduceable with the handbrake up and wheels chocked with an assistant observing in the engine bay or a 4 post hoist?

I’m going to recheck, but the only engine-related faults it’s been pulling (I use Carly) are 2F0D (which on N52 I understand to be a false radiator blind code) and 2EF5 (thermostat).

Vibration on acceleration/in gear isn’t isolated — I mean it feels like it’s from the front half of the car but it’s felt throughout the cabin. It’s not nearly as noticeable if I’m driving leisurely as it is under full throttle (which, particularly in 1st-2nd gear and especially around 2-4K RPM makes the car accelerate in a “choppy” manner) but even floating down the highway in 6th at constant speed there’s still a “roughness”.

At idle, you can visually see the engine vibrating, and you can even see/feel it pretty clearly if from the exhaust tips. Revving the engine in neutral does smoothen things out somewhat.

[850CSi]

Originally Posted by JonOhh

My 330i has a bit of vibration at idle, but is smooth under any other circumstance.

Are the spark plugs due for a change? Does it seem like the engine itself is not producing power smoothly (misfire, and so on) , or that its coming from somewhere else?

Plugs are probably due for a change, and that might be part of it. One issue here is I think the cause might be more than one thing. And so I’d like to eliminate everything but the DMF because that’s by far the most involving fix.

[850CSi]

Hard to see but... Is this what people are referring to when they talk about failing DMFs puking out a bunch of gunk? (Left side in the gap)

There was more of that, which I initially thought to be gummed up engine oil from my leaking oil pan.

For what it’s worth I haven’t clearly noticed anything wrong with my clutch though I do recall a judder at times.

I did have my CDV removed about 60k miles ago.

[Mantraxalos]

That's probably it. My brother has a 330i and it started feeling grainy whenever he would rev the engine. Just not smooth, but no wobble. Grainy is the best word to describe it. When he changed his starter we saw all the gray colored muck inside by the gear. The DMF failed. He's still driving it as is even though I told him not to.

[850CSi]

Alright, bumping for some advice.

I've changed the flywheel (which was totally destroyed, had a big hole in it), clutch, coils, and spark plugs. Engine and transmission mounts are also new.

But, while much better than before, I still have some roughness/vibration that I am trying to chase down.

It manifests most clearly when I first get on the throttle, and smooths out (but not completely) as RPMs increase.
Idle and revving at idle are buttery smooth.
No codes.

The car drives well enough that I think I probably put everything back together correctly when I had the transmission out. But, maybe not.

Anyone have any ideas? Driveshaft or harmonic balancer? Is it possible that it could just be my totally dead suspension? I don't think it's really speed dependent, so while my wheels and tires probably need some work, I doubt they're the culprit.

[E92William]

I know on the 335D the harmonic balancer is a seen as a maintenance item, I don't think so anywhere near as much in the N52 though. Maybe you could throw a known good used one in to try out though I doubt it.

I'd be inclined to blame the driveshaft but you say it also does it at idle, i think there's a chance these are many issues compounding into one. My car used to behave like that when my thrust arm bushings had basically collapsed. It was very inconsistent but sometimes on acceleration it would feel like a driveshaft coming apart. Lots of vibration from the wheel too at times.

[850CSi]

So, after my most recent work (flywheel, clutch) it's pretty damn smooth at idle.

I agree that I'm probably still dealing with multiple causes.

You could be right about thrust arms. My entire suspension is completely original at 170k.

[lowrydr310]

Originally Posted by 850CSi

Alright, bumping for some advice.

I've changed the flywheel, clutch, coils, and spark plugs. Engine and transmission mounts are also new.

But, while much better than before, I still have some roughness/vibration that I am trying to chase down.

It manifests most clearly when I first get on the throttle, and smooths out (but not completely) as RPMs increase.
Idle and revving at idle are buttery smooth.
No codes.

The car drives well enough that I think I probably put everything back together correctly when I had the transmission out. But, maybe not.

Anyone have any ideas? Driveshaft or harmonic balancer? Is it possible that it could just be my totally dead suspension? I don't think it's really speed dependent, so while my wheels and tires probably need some work, I doubt they're the culprit.

Usually any vibrations when you're first accelerating are caused by a bad giubo or center support bearing. Could be the joints on the driveshaft or even axles too, but check the driveshaft coupler (giubo) and center support bearing first.

I doubt it's the harmonic balancer unless it's REALLY messed up. The pulley on my 325i wobbles quite a bit but there are no vibrations.

[850CSi]

Forgot to mention I also swapped the giubo.

But thanks I think I'll get the car back up on my lift, double check that I did everything correctly, and check out my center bearing and axles. I'm tempted to just get another driveshaft and see if that does anything.

[E92William]

I've seen people opt for just getting a new driveshaft and at first I shrugged at that but now it seems smart because you can completely rule out any issues with it then. My center support bearing was definitely very soft and starting to have surface cracks at about 115k. I just changed the bearing and guibo at the transmission output shaft. Also have one by the differential but it seems most people dont

[850CSi]

Originally Posted by E92William

I've seen people opt for just getting a new driveshaft and at first I shrugged at that but now it seems smart because you can completely rule out any issues with it then. My center support bearing was definitely very soft and starting to have surface cracks at about 115k. I just changed the bearing and guibo at the transmission output shaft. Also have one by the differential but it seems most people dont

Yeah the center bearing is not an easy part to replace. Problem is that a brand new driveshaft is $$$$ and you’re sort of gambling if you pick up a used one.

[850CSi]

I put on some snow tires a couple of days back. That solved a piece of the puzzle -- car is a little smoother now.

I neglected to mention that I've swapped to a 3-stage manifold/DISAs but have NOT applied the bimmerlabs tune yet to me DME. Could that explain some roughness, especially at full throttle, lower RPMs in lower gears?

[MightyMouseTech]

Originally Posted by 850CSi

I put on some snow tires a couple of days back. That solved a piece of the puzzle -- car is a little smoother now.

I neglected to mention that I've swapped to a 3-stage manifold/DISAs but have NOT applied the bimmerlabs tune yet to me DME. Could that explain some roughness, especially at full throttle, lower RPMs in lower gears?

Currently running the same, actually made it a little smoother.

Your problem sounds like a worn inner CV joint.

[850CSi]

Originally Posted by MightyMouseTech

Your problem sounds like a worn inner CV joint.

Thanks for that suggestion. Anything in particular I should check for? The boots look good, and the only play I can feel is in/out along the joint's axis from the diff to the wheel. I don't hear clunking or anything like that.