[Spankey McCheeks]

Hello people.

This is my first time ever posting here so excuse me if I'm posting in the wrong place/forum.

I've recently purchased an '08 E92 330xi which has the N53B30 engine. It's pretty high mileage (240k KM) so there's bound to be some maintenance required to get it into passable shape. I've not yet started work on that but I've ordered a handful of suspension components, intake manifold gaskets, CRC valve cleaner, the list goes on. Most issues are pretty obvious in their causes and not worth really worrying about. There's one issue though I'm not sure about and I'm almost afraid to ask since it might get very expensive real quick.

As seen in this videohttps://www.youtube.com/shorts/cpMUByWOrr8, when the engine is cold ("cold" as in not driven for at least a few hours, not "cold" as in below freezing temps) it experiences very uneven idle revs. The revs fall to just around 500, sometimes almost 400, before rushing up to 7-800 almost as if to try to keep itself from stalling.

Now, IF this problem was constant I could imagine the injectors were failing (though that might still be the case) but the issue here is that this problem only appears AFTER driving for about a minute when the engine is cold and goes away completely after 8-10 minutes of driving. Like, shouldn't the issue be there from start?? This is what I can't really wrap my head around. Has anybody experienced anything similar to this?

[Phil325i]

First step...get your fault codes read.

[Spankey McCheeks]

Originally Posted by Phil325i

First step...get your fault codes read.

I went to BMW to have a recall addressed and asked them to also take out a copy of all codes while they were at it but of course they forgot and cleared the codes before saving them. It hasn't ever given me a check engine light though.

[TheHazelNut]

Possible pcv,ccv failure causing vacuum leak. you mentioned swaping the intake manifold gasket could have caused damaged to ccv hose or simply not torqued/fasten everything down tightly. when the engine heats up it can cause metals/plastics to expand alleviating the issue.

If you have no codes then it shouldn't be a big problem but it might be expensive since you have nothing pointing you in the right direction and who knows how many parts will have to be thrown at it until you get the problem solved.

[Spankey McCheeks]

Originally Posted by TheHazelNut

Possible pcv,ccv failure causing vacuum leak. you mentioned swaping the intake manifold gasket could have caused damaged to ccv hose or simply not torqued/fasten everything down tightly. when the engine heats up it can cause metals/plastics to expand alleviating the issue.

If you have no codes then it shouldn't be a big problem but it might be expensive since you have nothing pointing you in the right direction and who knows how many parts will have to be thrown at it until you get the problem solved.

Haven't swapped the gaskets yet. Planning on doing a valve cleaning since I doubt its been been done, ever. Will have a look at the PCV/CCV and correlating hoses while I'm in there. I have another problem though. I usually check for part numbers through RealOEM https://www.realoem.com/bmw/enUS/par...-E92-BMW-330xi but I can't find so much as a mention of any Characterized Control Valve (CCV) nor Positive Crankcase Ventilation (PCV). Am I just being stupid?

[TheHazelNut]

Originally Posted by Spankey McCheeks

Haven't swapped the gaskets yet. Planning on doing a valve cleaning since I doubt its been been done, ever. Will have a look at the PCV/CCV and correlating hoses while I'm in there. I have another problem though. I usually check for part numbers through RealOEM https://www.realoem.com/bmw/enUS/par...-E92-BMW-330xi but I can't find so much as a mention of any Characterized Control Valve (CCV) nor Positive Crankcase Ventilation (PCV). Am I just being stupid?

Id double check just to confirm but the part number should be 11157559527 "Vent Hose", goes from back of VC to intake manifold. i may be mistaken but the actual pcv/ccv unit is built into the valve cover itself.