Rough idle/start in cold weather?

[sidmiller]

BMWguy:

Did you make a list of all of the suggestions everyone gave me? I literally wrote down everything and took the list with me. I basically 'forced' the tech to sit down and give me answers for each potential fix. There are a lot of good suggestions from these guys. They are all very helpful. A couple of guys mentioned their 01's, so maybe that will help you go in a specific direction.

Good luck and keep us posted.

[vinuneuro]

If the problem only occurrs when it's really cold, the problem is certainly the oil-separator.

[BMWguy]

Sidmiller, Vinuneuro. Thank you I was able to put together a list. I also was able to start the X5 this afternoon (although snowing in NJ) the temps are about 28. It bucked and "stumble" for about 5 minutes then stalled. I restarted it and it ran and idle like nothing was wrong. Again on Monday day morning at 9 degrees it wasn't even attemping to stay running. What else can you tell me about the oil seperator?

I agree this is a great site and have seen me through some tough times, but again my X5 has let me down and I'm driving the E30 in some very bad snowy conditions.

Thanks

[vinuneuro]

Originally Posted by BMWguy

Sidmiller, Vinuneuro. Thank you I was able to put together a list. I also was able to start the X5 this afternoon (although snowing in NJ) the temps are about 28. It bucked and "stumble" for about 5 minutes then stalled. I restarted it and it ran and idle like nothing was wrong. Again on Monday day morning at 9 degrees it wasn't even attemping to stay running. What else can you tell me about the oil seperator?

I agree this is a great site and have seen me through some tough times, but again my X5 has let me down and I'm driving the E30 in some very bad snowy conditions.

Thanks

Search. It's been covered many many times.

[JCL]

Originally Posted by vinuneuro

If the problem only occurrs when it's really cold, the problem is certainly the oil-separator.

A few degrees below freezing wouldn't qualify as really cold, though, and an oil separator problem doesn't usually show as a stalling/bucking problem first.

I suggest that BMWguy have his mechanic hook up a BMW diagnostic computer and see what the vehicle tells him is wrong, whether fuel, vacuum line, or ignition related. That is certain to be more accurate than our telepathic diagnosis attempts.

[vinuneuro]

Originally Posted by JCL

A few degrees below freezing wouldn't qualify as really cold, though, and an oil separator problem doesn't usually show as a stalling/bucking problem first.

I suggest that BMWguy have his mechanic hook up a BMW diagnostic computer and see what the vehicle tells him is wrong, whether fuel, vacuum line, or ignition related. That is certain to be more accurate than our telepathic diagnosis attempts.

That's how it happend for our E53 when we had it and fpr others as well. How many other problems arise only in cold temps? If it's ignition related or there's a vacuum leak, the issue would manifest regardless of temperature. I can't think of any situations that would cause a fuel problems only in cold weather either.

Maybe using the word certainly was a bit too strong, but ruling out other potential causes, and the pattern of cold weather problems with these engines, odds are that his problem is the oil separator.

[JCL]

Yes, it could be related to an oil separator problem. What I picked up on was that when it stalled, it immediately restarted and ran fine. That doesn't sound like a frozen line or valve, it sounds like an electrical problem (or, by extension, a fuel problem relating to an electrical sensor or control).

I stick by my comment that remote control failure analysis is chancy at best

[BMWguy]

An update. Some how we have to factor in the cold temps. When it is above 35 it starts and runs fine. 2 weeks ago when it wouldn't start at my office I had it flat bedded to my guy and that Monday morning it started and he drove it into the shop. He put the computer on it and it read a number of mis-fired codes. He found a sticking in-take of some kind and a Vanos codes which he dismissed.

I found an article about the vanos on the net and sent it to him. He foward to his BMWTech.com or something like that and the response was that a number of E53 owners had that replaced every winter and although the cold start was better it didn't solve the problem in very cold weather.

Thanks again

[WAYNE'S X5]

Hi, mine had a similar problem but also stalled a couple of times at traffic lights(auto mind you).there is a small intake pipe at the back of the engine (centre, right at the back just at arms reach if your a gibbon)these soften up and collapse then block! bmw advise to replace them every couple of years at about £15 for the part but only on the petrol models.Also check that the plastic expansion tank attached to the underside of the large intake pipe at the front leading into the airbox is not cracked!!!!
GOODLUCK.

[BMWguy]

Ok guys not much to report but I don't want this to die. I think it is a common problem that we need to get to the bottom of. I was going to take it to my guy this weekend but I didn't want another $500 bill. I ordered the X5 book from Bently. I also was able to start it today with a slight 'stumble" it reached idle and ran fine. I think I'm going to repair stuff I can do. Fuel filter, tubing etc.

I'm open for any updates.

Thanks