Vanos solenoids or breather valve? Idle trouble

[fitzbane]

So my car is giving me issues at idle - seems pretty much like the symptoms people have described here with the fix being replace the fuel tank breather valve.

Symptoms - after car has been driven a little bit and warmed up, at stop lights my idle will drop below 500, then will overcompensate to ~1000 to catch back up. Sometimes it will drop low enough to stall / throw itself into neutral, although this is somewhat rare. It looks a lot like videos in threads like the following, although fuel type / amount does not seem to make a difference to me.

http://www.m3post.com/forums/showthr...t=Erratic+idle

So anyway I finally decided to take it in and have it looked at, the shop (BPC in Raleigh) says its not the breather valve, its my VANOS solenoids and quoted me $1755 to replace all four. Seems expensive to me, they also wanted $1500 for o2 sensors, which BMW quoted me only $1000 . Anyone have any thoughts on this? I haven't seen much at all about the S65 VANOS solenoids giving people issues here.

Just had a rock destroy my windshield 3 days ago also..wallet is hurting

[drummer20]

man I would be hard pressed not to just buy the fuel tank breather valve and replace it myself... you might get away for less than $100 and a Saturday. I hadn't read about trouble with the VANOS on this generation. That was common on previous generations but not really this one. Also that issue you describe sounds dead nuts fuel tank breather valve to me...does it happen more right after you fill up the tank and then kinda fade away until another refuel?

[fitzbane]

Honestly I don't notice a difference in when it happens - its definitely happened with a lower tank, but I generally don't go below 1/4 tank and I also drive 60+ miles/day so I go through a lot of gas cycles

[drrust]

I had the breather valve issue. It only did it after a fill up. If it is happening at other times for you, then it may be something else.

Do you know if there were any codes? I did not have any with the breather valve issue.

The breather valve is about $90 and there is a nice DIY. It may be worth a shot.

[kscarrol]

What drrust said! You saw my video in that thread but for me the idle issue happened almost exclusively after filling up. I don't recall having any idle issues as fuel levels dropped. Check to see if the car is throwing any codes but the fuel tank breather valve will not throw any codes...

[fitzbane]

Originally Posted by kscarrol

What drrust said! You saw my video in that thread but for me the idle issue happened almost exclusively after filling up. I don't recall having any idle issues as fuel levels dropped. Check to see if the car is throwing any codes but the fuel tank breather valve will not throw any codes...

I've had this problem for going on 8-9 months and have had codes read at bmw/indy shops multiple times and it never threw a vanos code until today. I suppose its possible the vanos could be busted in addition to the breather valve

[yidgyi]

I had he issue with idle and just went to the dealer and they replaced the idle breather valve and t was fixed. I would try the idle breather valve first.

[fitzbane]

Just as a quick follow up to this - I drove my car at low gas ~1/4 tank for a while to confirm, and yes, this problem didn't occur a single time. I'm pretty convinced the solenoid code has nothing to do with the idle problem as suggest by BPC. Either way it doesn't matter now, as I traded the M3 to carmax today. Sad times.

[jester17]

Eeek! What'd you trade it for? And di you trade it for just the windshield/breather issues, or were there other factors?

[fitzbane]

I got a 4runner for now while I look for the perfect S2000. there were other factors, unfortunately