kushane

My 2005 530i started having a rough/uneven idle along with lean codes which I traced to a vacuum leak in a CCV hose (the one between the dipstick tube and the CCV). I also put in 6 new NGK spark plugs since I was at 75k too. A short while later it started throwing large clouds of blue/white smoke during startup and it turned out the CCV was blown altogether. So I put in a new CCV and replaced the remaining hoses as well and things seem fine now except for a slight vibration during idle that wasn't there before. The vibration can be felt through the steering wheel, seats etc. I sprayed electrical cleaner around the ccv and the hose connections and can't detect another vacuum leak. Couple of thoughts:

1. I also cleaned the throttle body while I had it removed. Could I have damaged anything when I manually moved the throttle plate open/closed?

2. Since the ccv blew after I put in the new plugs, could the oil being sent to the combustion chamber have fouled the plugs and could that cause a vibration?

3. Any other thoughts on what this might be?

No error codes are being thrown although my butt dyno suggests it might be slightly down on power any my gas mileage maybe slightly lower as well.

Thanks,

turboawd

how long did you drive the car after the repairs?
the computer may need a little time to relearn....

turboawd

also, if you were burning oil like you said, you may have coated your O2 sensors a bit.
i say drive the car for a while, get it hot, run it through its rpms, then see if all is good.

kushane

Been about 300 miles since then over about a week now. Although to your point, I feel the vibration is a little less pronounced now than is was earlier in the week.

I just took out a couple of the plugs to take a look and the only thing I noticed was that it looked lighter compared to the old plugs, almost like it was running a bit lean, but its been a while since I've seen a used plug in good condition and this maybe normal.

The pic below shows an old plug on the left and a new one I just pulled out on the right.

kushane

Wanted to close the loop on this issue I was experiencing. While I was waiting on my transmission to cool down during a drain and fill, decided to take out the Idle Control Valve (ICV) and give it a good cleaning. There was enough carbon buildup that the tabs that open and close inside the valve weren't moving. A quick spraying with carb cleaner and it broke free and there was quite a bit of carbon residue that drained out. This has fixed my idle vibration about 90% and I think the very slight vibration left may have been there before and is therefore normal. Since this issue started when my CCV broke, wondering if the fumes from the broken CCV caused the ICV to clog up? Took about 30 minutes total and the hardest part was inserting the ICV back into the rubber grommet on the intake. Space is a bit tight and the ICV needs to be aligned correctly before it would insert back in.

To summarize:

Symptoms: vibration during idle felt through the steering wheel. Also, upon coming to a stop, the revs would initially drop below ~550 for about a second before settling at ~650.

My resolution: remove and clean ICV

BenAnd

Hi kushane

Had just the same issue with a faulty CCV , and after change of this , the same feeling of "more" vibration at idle than before.

Did also a cleaning of the ICV , and now it seems to be "back" as it was before :-)

So the conclusion must be , it's a good idear when cleaning/changing the CCV , also to clean the ICV.

Best Regards
BenAnd