Rough idle/start in cold weather?

[4MoJoe]

I found my paper work and this is what they listed: "Customer states upon cold start and when driving the car it bucks and runs very poor check and advise. Checked and found no faults stored in computer. Found TSB relating to customers concerns (tsb dated 12-05-07). Programmed DME and Transmission Control Module."


I'm sure your dealer can look up the TSB on yours and do the DME and TCM programming.

Good luck!

Originally Posted by sidmiller

4MoJoe, that would be great if you could get me any information from your paperwork! I would be very appreciative. I think we have updated the TCU software. Not sure about the ECU. What is the ECU? Interesting that you had the same problem...

[sidmiller]

Thanks 4MoJoe! I will definitely ask them. I am scheduled to go back in on Monday.

Thank you again!

[sidmiller]

Wow, thank you, StanF18! You know, I'd wondered if maybe I got some bad gas or if I needed to consider some kind of treatment in the tank. This is a great plan and I will definitely try it. I am taking it in again next week one last time, but will try this protocol on my own anyway.

When you say "Chevron's Techron additive is also not bad. You may want to ask around about it..." do you mean as an alternative to the lucasoil or as Iso-Heet? Or as an 'every fill up' additive?

Thanks again for all the follow up! Very nice of you! I'll let you know what comes of all this...

Sid

Originally Posted by StanF18

OK, you're using good gas. I've heard that Chevron is pretty good. Shell is another good one.

I would try a couple of simple things before you start going crazy and spending lots of $$$ on parts. Your problem may be as simple as water condensation in the gas tank and fuel lines, or contaminant build-up, or both.

After you fully finish off your current tank of gas, pour in one treatment of a high-quality fuel injector cleaner right before you fill up again. I use the small Lucas Oil brand bottles.

http://www.lucasoil.com/products/dis...tid=2&loc=show

Use one 5.25 oz bottle per fill-up. The neck of the bottle won't fit into the E53 gas tank, so get a funnel with a narrow stem. Empty the bottle out completely and then fill up as usual. There may be other good brands as well, but this is what one of the guys at Auto Zone recommended and I was not disappointed. Stay away from STP, I've heard their products are not nearly as good. Do this for your next 2 fill-ups and see if the situation improves.

If you're still having a problem, use a high-quality water remover for your 3rd fill-up. I've used Iso-Heet. Same thing, 1 small bottle per tank. I think the isopropyl alcohol products are better than the methanol (regular Heet). This will bind up any excess water in your fuel system and remove it.

I was having a rough idle and engine knocking problem back in November after I possibly got some less than optimal gas. Also, I had just gotten Dinan exhausts, so the sound was amplified even more. But after a couple of tanks of Lucas Oil treatment and one tank of the Iso-Heet, the stuttering is much improved. Once it's fixed, do not to use the Lucas on every fill-up. Every other fill-up is good.

BTW, I read in one of the threads that Chevron's Techron additive is also not bad. You may want to ask around about it.
Also, you may want to replace your fuel filter to prevent the build-up of additional contaminants. My part+labor on that came to $250 at my local dealership. But try the treatments first.

Based on all the guys that responded so far, it looks like the X5 does have a tendency to idle a little rougher in freezing temps. So you might not get it to 100% smoothness for those cold winter starts. But it should not sound like a Harley or a buck like a horse once you've cleaned out your fule system and injectors. That's what worked for me.

Finally, if you're anticipating a super-Arctic super-cold morning, try not to leave your vehicle with an empty tank overnight. Keep it as full as possible to prevent water/ice buildup inside the tank. Of course this is not always possible, but I did read that empty tanks don't do as well in frigid temps. If it's filled with gas, there's no room for the water to creep in.

Good luck!

[StanF18]

Originally Posted by sidmiller

When you say "Chevron's Techron additive is also not bad. You may want to ask around about it..." do you mean as an alternative to the lucasoil or as Iso-Heet? Or as an 'every fill up' additive?

Thanks again for all the follow up! Very nice of you! I'll let you know what comes of all this...

Sid

I think Chevron adds a small amount of Techron to their gasoline as is, so you're already getting a little Techron every time you fill up with them. But they also sell a more concentrated bottle than you can add to your tank, for some extra detergent action to get rid of gunk. I meant as an alternative to the Lucas Oil. I would use one or the other, not both. The Iso-Heet is a separate type of product, purely for water removal. By the way, I mis-spoke. It doesn't really "bind" to the water, it just mixes with it (dissolves it) and this new ispopropanol-water mixture will burn up more efficiently in the chamber.

[JCL]

To the OP:

The problem appears to be intermittent, ie you don't have it regularly but more so when cold starting. That is not consistent with a fuel problem, which would tend to remain, particularly if the problem is repeatable and always occurs when the engine is cold.

Chevron gasolines all contain Techron. If you use it regularly it is unlikely that you have dirty injectors, the various grades all contain sufficient Techron to keep the fuel injectors clean. If you have water in the tank, fine, but I wouldn't use a product to remove it more than one time. If you got a bad tank of gas you would likely have burned it up by now. I am a big fan of Techron, and know it from when I used to work at a Chevron fuel distributor. I am suggesting that you proceed cautiously on its use, though.

Your manual contains instructions not to use any fuel additives. After the vehicle is out of warranty, feel free to go ahead. However, using them yourself when the dealer is in the process of diagnosing a rough idle may simply confuse the issue. Your vehicle is under warranty. The dealer has noted the problem. Simply return the vehicle to them and let them do their job. If they can't fix it, find another dealer. It may take more than one trip, and that is unfortunate, but it doesn't mean that they can't methodically work through the list of potential problems until they find it. Suggest you let them do their thing. If the dealer is unable to resolve it after additional visits, you can ask them to bring the regional BMW tech rep in, and meet him at the dealer service department.

Good luck.

[vinuneuro]

We had this exact problem twice with our 01.

First time around: Our regular dealer couldn't figure it out either. Tried a different one, and they got it on the first try. Thermostat and an ignition coil replaced at 35k miles. I believe the coil was replaced in the process of diagnosis (something for your techs to look at for sure), but the culprit was the tstat.

Second time around: Plugged crank vent line/oil-separator clogged.

[bimmer]

Please do not assume that the following is the culprit for SidMiller's issues, as the previous threads contain valid root causes, but I do want to add that the VANOS unit could be a culprit, as similar symptoms are experienced in other BMW engines with known bad VANOS units. The nature of VANOS failures do not necessarily generate Fault Codes, which is why this unit is such an illusive failure.

The E36, E39 and E46 have a high level of failure in the VANOS units due to the seals that are used in the units, which do not hold up well to synthetic oil and high temperatures. Why would BMW use correct seals in the X5 engines?

Before someone jumps on me for possible "bad" information or hi-jacking this thread, I am looking at the VANOS as the possible reason for my 2005 X5, 4.4i which is experiencing the following (similar to SidMiller's issues):

1. Bad MPG (<16 MPG highway - easy throttle)
2. Rough Idle (notable at cold start, but present at other times)
3. Poor acceleration under 3000 RPM (always)
4. Valve chatter (sometimes - sounds like clicking)
5. Engine noise from VANOS area (both sides of engine - sounds like a muffled chainsaw)

This all started around 14000 miles, after the dealer changed oil and left it 3 quarts low, which required me to return to the dealer after engine started #4 stated above. They took the car around to the service bay and they returned it shortly stating that nothing was wrong, but the oil "magically" was full.

Unfortunately, the seals that fix the E46 vanos units offered by http://www.beisansystems.com
probably won't fit the V8 VANOS units (N62 bi-VANOS). I want to get similar seals and rebuild the VANOS units on my vehicle and I will provide my findings to this forum.

(ref: BMW X5 Service Manual, p 100-7, Bentley Publishers)

[sidmiller]

My humblest thanks again to StanF18, and now to JCL, vinuneuro, and bimmer! Very nice of you all! This is all great information and all I can say is "the more the better". If I can continue to walk in the door at the dealer and have possible fixes, I am all for it. Everything you guys suggest, I keep and take with me each time. Of course, each suggestion is met with, "...you have a different engine... that would have shown up on the diagnostic... we checked that..." etc. etc. Do we feel that it is 'us against them'? I don't mean to, but it's getting there.

I should clarify: my service advisor and service tech have been very nice and I don't get a bad vibe from them... yet... so I am trying to remain open minded and do what I can to get my car running better.

Also, that idle adjustment they made last week (from a .2 to a .8 - or something like that)? TERRIBLE! The throttle cannot seem to find it's place and I end up bucking down the road or away from stop lights. SO... back to the previous settings.

My plan is to take all these suggestions and any others, and when I go in on Monday, have a new list ready.

Keep em coming, friends, if anyone thinks of anything else. As always, I'll keep posting outcomes and changes in an effort to help anyone else to avoid these same problems.

Sid

[sidmiller]

Hey friends. My apologies for not posting sooner. Out of town, busy, you know... typical stuff...

Here is my final update:

Last trip to the dealer they returned the idle settings back to a .3 or something like that. They said they made one other small adjustment but didn't give me much detail. They also are sending an entire report of the problem to the New Jersey office and asking that a regional rep look over everything and then plan to check the car when he is in town. Not sure how accurately I am relaying this information, but in short, they have escalated the problem and are looking to the 'higher powers that be' to help us with the issue.

In the meantime, now that the idle has been changed back, there is no more 'bucking' down the road when creaping in traffic, so I am VERY pleased about that. We have only had a few cold mornings here where I could test out the rough start and crazy idle. On those days, I didn't experience the problem at all, which is weird because we are back to all the original settings that we had before when the cold start was such a problem.

Could it be that I really did get some bad gas for a few tanks? I have switched stations for the last couple of fill ups just for the sake of trying something different.

Seriously, all this headache, all of the help from you guys, and it might have been as simple as the gas station/fuel quality? Nah. Tell me it isn't so.

[BMWguy]

Hi guys

Although I hope your problem is resolved please don't let this one die. I have an 01 X5 with the same problem but living in NJ I have a few more cold mornings (9 degrees yesterday). Mine began about a month ago when became really cold. All of the above problems. Please give something I can take to my machanic.

Thanks