One for the experts on vacuum systems!

[ninja_zx11]

Here is the diagnostic procedure described in ISTA.If you can check the amount of vacuum and vacuum build up time as shown in PIC 3.

Pic 1 shows location of changeover valve.

[mobilejo]

Thanks for that. I may need to get ISTA/RHEINGOLD.

Your issue sounds a little different to mine as mine is worse at idle than any other speed - have you looked into the 'driveshaft recall' issue for these cars: Recall: Front driveshaft

Apparently some of them had excessive slop and were to be replaced. Could explain your shudder.

[ninja_zx11]

Originally Posted by mobilejo

Thanks for that. I may need to get ISTA/RHEINGOLD.

Your issue sounds a little different to mine as mine is worse at idle than any other speed - have you looked into the 'driveshaft recall' issue for these cars: Recall: Front driveshaft

Apparently some of them had excessive slop and were to be replaced. Could explain your shudder.

It doesn't look like my issue is related with drive shaft as vibrations are rpm dependent not speed.Also mine has a Guibo Joint not universal joint as its 2009.Now i am just ignoring it.Even my wife doesn't feel anything while driving.Looks like i am too sensitive.

If you are getting too much vibrations while idling then you may need new mounts.

[mobilejo]

Originally Posted by ninja_zx11

It doesn't look like my issue is related with drive shaft as vibrations are rpm dependent not speed.Also mine has a Guibo Joint not universal joint as its 2009.Now i am just ignoring it.Even my wife doesn't feel anything while driving.Looks like i am too sensitive.

If you are getting too much vibrations while idling then you may need new mounts.

It went into my local BMW dealer today, the mechanic took a test drive with me and said he could feel it - exactly as I described. I left it for them to look for the cause and when they called later that day they said they can't find anything wrong.

I told them the mechanic already said he could feel the vibrations; apparently it was a different mechanic that tried to diagnose it to the one that drove it earlier

I told them to keep it overnight and have the first mechanic look at it tomorrow.

I hate the way they say "no fault" when they mean "we can't find the cause of the fault". They said the engine mounts looked fine - of course they 'look' fine, doesn't mean they are working as they should!

I imagine these engine mounts are much like the control arms - impossible to diagnose while on the car unless they are totally dead because they are so heavy duty they only show up problems under the stress of being in use yet show nothing when tested by hand. Sometimes an educated guess is the best you can do but they rely on fault codes and things being visibly broken before they are willing to suggest something as a cause.

[ninja_zx11]

Originally Posted by mobilejo

It went into my local BMW dealer today, the mechanic took a test drive with me and said he could feel it - exactly as I described. I left it for them to look for the cause and when they called later that day they said they can't find anything wrong.

I told them the mechanic already said he could feel the vibrations; apparently it was a different mechanic that tried to diagnose it to the one that drove it earlier

I told them to keep it overnight and have the first mechanic look at it tomorrow.

I hate the way they say "no fault" when they mean "we can't find the cause of the fault". They said the engine mounts looked fine - of course they 'look' fine, doesn't mean they are working as they should!

I imagine these engine mounts are much like the control arms - impossible to diagnose while on the car unless they are totally dead because they are so heavy duty they only show up problems under the stress of being in use yet show nothing when tested by hand. Sometimes an educated guess is the best you can do but they rely on fault codes and things being visibly broken before they are willing to suggest something as a cause.

Agree with you.Unfortunately that's how most of the times stealerships come back with universal answer "its totally normal and everything is working as it should be".

If you can get ISTA then you can also try to run smooth running control measurements and you can also measure vacuum at the mounts by activating that function.I think if there is not enough vacuum available to the mounts to shift to hard mode then mounts will remain in soft mode all the time and can cause premature wear on the mounts as there will be more movements.you can even do that test without ISTA by reving the engine upto 1000~1500 rpms and checking the vacuum if it switching on/off quickly and building upto the spec shown in ISTA.

[mobilejo]

Originally Posted by ninja_zx11

Agree with you.Unfortunately that's how most of the times stealerships come back with universal answer "its totally normal and everything is working as it should be".

If you can get ISTA then you can also try to run smooth running control measurements and you can also measure vacuum at the mounts by activating that function.I think if there is not enough vacuum available to the mounts to shift to hard mode then mounts will remain in soft mode all the time and can cause premature wear on the mounts as there will be more movements.you can even do that test without ISTA by reving the engine upto 1000~1500 rpms and checking the vacuum if it switching on/off quickly and building upto the spec shown in ISTA.

Yeah I'm going to order ISTA and cable etc tonight I think! I also need a vac guage.

[mobilejo]

Originally Posted by ninja_zx11

Agree with you.Unfortunately that's how most of the times stealerships come back with universal answer "its totally normal and everything is working as it should be".

Ninja_Zx11 - In your other thread when you first documented the issue, you said that you had vibrations at idle and when driving at certain RPMs. Now you don't appear have it at idle anymore - is that correct? If so, did changing the engine mounts solve the idle problem but not the driving rpm vibrations?

I am going round in circles trying to find the cause of mine and I keep coming back to engine mounts. When I bypass my engine mount vac solenoid and connect the mounts direct to a constant source of vacuum, I get no vibrations while driving - it's like a different car completely. But at idle it's the same.

My vac system appears to be working to spec according to BMW who 'said' they tested it. My own test of just checking for vacuum when revved did show that there is vacuum when revved so it's working to an extent definitely.

soooo, why does giving the mounts constant vacuum make the car drive better in all rpm's except idle? I can only guess that my mounts have deteriorated to an extent that when in the soft state, they are not performing adequately. When hard they do their job and so having them hard all the time (while not how BMW intended) produces less vibes than having them soft upto 1050rpm. Perhaps the idle rpm is just too low for hard mounts to overcome those vibrations

I went and tested another 2011 with identical mileage (40k) today and at idle the steering wheel had the same vibrations but when driving it felt 'smoothed out' and much less vibrations than mine. This has just got me thinking that maybe these mounts are starting to deteriorate at this mileage.

[ninja_zx11]

Originally Posted by mobilejo

Ninja_Zx11 - In your other thread when you first documented the issue, you said that you had vibrations at idle and when driving at certain RPMs. Now you don't appear have it at idle anymore - is that correct? If so, did changing the engine mounts solve the idle problem but not the driving rpm vibrations?

I am going round in circles trying to find the cause of mine and I keep coming back to engine mounts. When I bypass my engine mount vac solenoid and connect the mounts direct to a constant source of vacuum, I get no vibrations while driving - it's like a different car completely. But at idle it's the same.

My vac system appears to be working to spec according to BMW who 'said' they tested it. My own test of just checking for vacuum when revved did show that there is vacuum when revved so it's working to an extent definitely.

soooo, why does giving the mounts constant vacuum make the car drive better in all rpm's except idle? I can only guess that my mounts have deteriorated to an extent that when in the soft state, they are not performing adequately. When hard they do their job and so having them hard all the time (while not how BMW intended) produces less vibes than having them soft upto 1050rpm. Perhaps the idle rpm is just too low for hard mounts to overcome those vibrations

I went and tested another 2011 with identical mileage (40k) today and at idle the steering wheel had the same vibrations but when driving it felt 'smoothed out' and much less vibrations than mine. This has just got me thinking that maybe these mounts are starting to deteriorate at this mileage.

I started that thread just after i purchased my 2009 35D. I was feeling faint vibrations at idle but more at driving at low rpms and it was kind of annoying after moving from jetta TDI.
Then i made dealer to change my both front vacuum controlled mounts.It made a difference but it was not like day and night.Then i drove another vehicle and it had same kind of vibrations at idle but while driving that vehicle felt smoother than mine.Its when i started to diagnose myself but i eventually gave up.The only thing dealer didn't replace was transmission mount. Couple of months ago i ordered new transmission mount but never got a chance to replace it.

[mobilejo]

I'd be curious to see what difference the trans mount makes on yours, and also whether a vac bypass like what I tried makes any difference.

It's really irritating that such good vehicles can be spoiled by the silly little things like this.

[mobilejo]

Well I had my engine replaced today and just like you Ninja, I notice a slight improvement but not a huge difference. Vibration is still there particularly at idle, but it's almost all in the steering wheel.

I noticed holdign the steering wheel by the controls (volume and phone buttons) you feel it much worse so now i'm just gonna keep my hands at 2 and 10 o clock - barely feel it there. So yeah, not much of a solution but instead a 'compromise'.

It does seem to be smoother when moving - less vibes at 1200 rpm which is where it was worse before. Still there but less.

During all this, I did go and test a few cars of same age and mileage and they all vibrated the same so I'm ready to give up and accept that maybe this is just the way these cars are...