high rpm/idle after replacing OSV

[cris88]

help pls! just replaced my oil separator valve (intake manifold cover-back wall) which solved the whining sound, but noticed high and intermittent idle. when i turn the engine off it goes to normal-about 600 or so then when i step on gas and release it doesn't come back to normal, it stays around 1000 sometimes even higher, also sometimes goes back to normal. I tried to isolate by removing the cable adjuster so i'm pretty sure it's not the adjustment (like bike cable). thanks!

'97 740iL

[m6bigdog]

It is possible your engine has a vaccuum leak.
It could be from a disconnected hose, bad hose or the internal intake manifold vent tube is not positioned correctly.
Your engine is OBD capable and I anticipate you DME will display fault codes.
Also, The last time I replaced the Crankcase Pressure Regulator some of the intake manifold and front cover gaskets were leaking and that caused lean miss and fuel trim fault codes. The engine was having missing while idling.

I'm not sure what parts you have replaced.
The Oil Separator (PN 11 15 1 747 066) is on the front of the engine. see Real OEM diagram.
http://www.realoem.com/bmw/showparts...54&hg=11&fg=15
The Crank case pressure regulator (PN 11 61 7 501 563) is on the back of the intake manifold. see Real OEM diagram.
http://www.realoem.com/bmw/showparts...37&hg=11&fg=40
The function of these parts are related but are functionally separate.

I would not recommend replacing the crankcase pressure regulator with the intake manifold on the engine since there is an internal tube that may not align with the CPR cover.
Rod...
BMWCCA GGC

[cris88]

you have good points that relates to what i am experiencing right now. i was in the perception that the vent tube was only meant for draining extra oil, no vacuum. this is the only part i was really in doubt after replacing my oil separator as it was loose, just clip on to the cover without screw or anything. how can i allign this, any technique i should do? also both my timing chain cover (gasket) is leaking now, is this possible source of rough idle? thanks a lot for the help.

[cris88]

clipped to the back cover. will this cause vacuum leak if loose?

http://www.realoem.com/bmw/showparts.do?model=GF83&mospid=47528&btnr=11_2254&hg=11&fg=15

[cris88]

i went back to check the vent tube that connect the back cover OSV to the actual oil separator, refer to the link from Rod. i found that the tube was not plugged in properly to the oil separator when i replaced the cover at the back. took another 2 hours for me but hey i'm glad i fixed it. i'm not a mechanic, just trying to save money (not time) for my baby. i'm a happy camper now. thanks!

symptoms:
high rpm at N and P
rough idle
poor pick-up at 1st and 2nd gear