Rough idle/start in cold weather?

[primetime]

Originally Posted by sidmiller

Hey Friends, here is an update on the outcome:

The dealer kept my X5 for a couple of days. When I got the call that it was ready, they told me everything they had worked on. Everything ELSE that was on my list. So I asked about the rough idle, and their response was, "Oh, let me check and see what we found out." Turns out, they upgraded the software. Okay... nice enough offer... but seems to be the easiest solution. So I said I'd drive it for a few days and see if it was any better at cold starts. At first, everything seemed great. Smoother shifting, better gas mileage, smoother starts, etc. I was actually pleased and almost dropped you guys a note to tell you. HOWEVER...

Yesterday morning, 30F degrees out. Started the car, and "The Jalopy Syndrome" was back and as strong as ever. Shaking back and forth, sounding like a Harley Davidson motorcycle but not as loud.

I am taking it back in tomorrow morning. Apparently, the SIB, the suggestions from you guys, the print out I gave them didn't seem to help. They went with the easy way out. I would like to ask if you guys have any more thoughts, shoot them to me. I'll bombard these guys with suggestions and tell them to keep the car until they have fixed it!

Thanks again, friends.

All of your symptoms describe a bad oil seperator...Especially about the bad gas mileage. This is what a member lojack said to me about mine

"the blowby and oil that is making its way into the combustion chambers (which is getting past the seperator) causes your engine to run lean and hot, and the computer picks that up and inceases the fuel, which is cold and rich.

After a while your milage will be horrible as the computer dumps more fuel into the chamber to keep from leaning out. I would advise not running it too hard and making sure to keep high octane in the tank until you get this solved."

My car did the exact same thing with the rough start and idle in cold weather...I also blew my valve cover gasket because of this..I'd ask your dealer about your oil seperator...

[sidmiller]

Thanks PrimeTime. I will add oil separator to the list!

Hopefully I'll get more before tomorrow morning!

[sidmiller]

Apparently, my friends, anything on my list, oil separator, O2 sensors, etc. were all ruled out due to diagnostics and due to the fact that some items were not applicable to my particular engine, manufacture date, etc. The Service Tech guy came out and sat with me to discuss everything.

He said he could try one more thing and that would be to adjust the idle to 'the other setting'. Something like from a .2 to a .8 or something like that? Not sure about my accuracy. Said it would change the throttle response a little, but may help everything.

Now, the car is doing well on cold starts. I am happy. HOWEVER. I was driving in heavy traffic this morning, very slow, speedometer barely registering. The car starts "bucking" along like a horse. Yesterday, the service tech told me there is something called "Slow Creep Buck" or something like that, that they can't pinpoint and don't have a fix for yet.

Either it idles like a Harley when cold, or it bucks like a horse going down the road. These are my options for my nice new, fairly expensive car.

At this point, I'm at a loss here, guys.

[primetime]

Originally Posted by sidmiller

Apparently, my friends, anything on my list, oil separator, O2 sensors, etc. were all ruled out due to diagnostics and due to the fact that some items were not applicable to my particular engine, manufacture date, etc. The Service Tech guy came out and sat with me to discuss everything.

He said he could try one more thing and that would be to adjust the idle to 'the other setting'. Something like from a .2 to a .8 or something like that? Not sure about my accuracy. Said it would change the throttle response a little, but may help everything.

Now, the car is doing well on cold starts. I am happy. HOWEVER. I was driving in heavy traffic this morning, very slow, speedometer barely registering. The car starts "bucking" along like a horse. Yesterday, the service tech told me there is something called "Slow Creep Buck" or something like that, that they can't pinpoint and don't have a fix for yet.

Either it idles like a Harley when cold, or it bucks like a horse going down the road. These are my options for my nice new, fairly expensive car.

At this point, I'm at a loss here, guys.

Jeez..sorry to hear that..I think i noticed a little slow creep buck myself in bumper to bumper highway traffic this morning....

[StanF18]

Sid, a couple of questions for you:

1) Do you have the stock exhaust or did you mod it?

2) What brand of gas are you using? And what octane rating?

[4MoJoe]

I had this same issue with my 2004 4.4i. I got it back yesterday from dealer and they updated both the ECU and the TCU (I think) transmission software. Yesterday driving home was very smooth. This morning (16 degrees) the car didn't hesitate and buck when I drove to work. I'm a bit worried tho as they found the oil 1 quart low and that makes me nervous...I had complained about valvetronic ticking when it was cold. With the addition of oil it didn't do that this morning. I don't have the paper work handy but I'll look and see what TSB they mentioned.

[sidmiller]

Originally Posted by StanF18

Sid, a couple of questions for you:

1) Do you have the stock exhaust or did you mod it?

2) What brand of gas are you using? And what octane rating?

No modifications. The exhaust is stock.

I tend to fill up at Chevron stations (that's the card I use) or Exxon and I use thier 93 Octane.

Thoughts, StanF18?

[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...

[E61Silver]

My 2005 4.4 had the same issue, it was so bad that it triggered the check engine light.

They replaced the variable timing motor and its better but still notice some roughness when its really cold.

[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!