Help! Very rough idle and whining sound

[BiTurbo]

Hi guys!

Just had those two weird problems!

Yesterday I used the car and all worked flawless. Today I start the car (its -14 Celsius outside) and 2 seconds after the engine dies.

I try to start it up again and then the idle is very very rough! The car literally shakes! After 20-15 secs I turn it off (and decide to take my gf's corolla)!

2-3 hours later I try to start it off again and, although the idle is a little better, you can still hear the whining sound for the first minute or so and then it disappears. (as per the video : http://www.youtube.com/watch?v=RfLzr9SfWG4) You can hear the whining sound pretty well at seconds 11-12 and 45-49 seconds.

The rough idle however doesn't go away for the entire video!

Any thought?

[BCS_ZHP]

Look at your battery, if its an original BMW battery look at the top of the negative terminal. 2 sets of 2 digit numbers will be stamped in the top of that negative terminal. The first 2 digit is the week, 1-52, and the second is the year, as in the week of the year your battery was produced. With that super cold weather I'm guessing if your battery is over 5 years old then lower voltage to the engine on start up is occurring, you probably have a misfire code on bank 1 or 2 because of it, the computer is trying to compensate for it and you get a rough idle. I couldn't hear the whirring noise enough to diagnose it.

[alexandre]

If you have time early tomorrow morning (say before 9am), come by my place and I can check it out :) just PM me your # and I'll text you my address. I have a scanner for codes, etc.

[echo46]

Agree with BCS, check the battery. I would also check for any cracks in the Upper and lower intake boots that might be causing a vacuum leak. Also check the DISA. Start simple, get the codes read and give us more info.

[BiTurbo]

Hi guys!

Thanks for the input!

As for the battery, I replaced it last month as it was completely dead! But even though I changed it, the start up still feel a little hard for my taste.

Ill try to get in touch with Alexandre as we are in the same area. I understand he has a code reader.

Thanks again for the input!

[Newjack]

Look at your battery, if its an original BMW battery look at the top of the negative terminal. 2 sets of 2 digit numbers will be stamped in the top of that negative terminal. The first 2 digit is the week, 1-52, and the second is the year, as in the week of the year your battery was produced. With that super cold weather I'm guessing if your battery is over 5 years old then lower voltage to the engine on start up is occurring, you probably have a misfire code on bank 1 or 2 because of it, the computer is trying to compensate for it and you get a rough idle. I couldn't hear the whirring noise enough to diagnose it.

This sounds accurate. If your engine is giving you any codes make sure to pull them and read them. Violent shakes sound like a misfire like Bruce said. If you check your lower intake boot you might as well clean the idle control valve while you are in there.

[alexandre]

I'm gonna check the car out next week, but yea I'm thinking ICV, MAF or a vacuum leak somewhere.

[echo46]

Yea, it becomes almost like a treasure hunt, especially if you get into looking at the CCV and all its pain in the butt hoses. I got so frustrated that I just replaced the upper and lower intake boot with Stett silicon and the CCV and all its hoses.

[Johnmadd]

Maybe just the alternator voltage regulator since you have just got a new battery.

[echo46]

I was thinking about this some more, could be the cam position sensor or crank position sensor.

[BiTurbo]

Newjack Thanks for the input! If it was misfire, shouldn’t I get a code? Ill check the lower intake boot and clean the idle control valve ASAP! Thanks!

echo46 I was thinking exactly the same about the cam position sensor… A buddy had an issue with that part and the symptoms were pretty close the same!

Johnmadd About the alternator voltage regulator, the other day, when I started the car, the whining sound was pretty bad and I noticed that when the indoor light were on, they were fluctuating big time with the whining sound!

Clearly there was a link with the whining sound and the alternator somewhat!


So alexandre is gonna come check the car next WE. Never thought I’d say that but I hope the symptoms will still be present!

Thanks again all!!

[echo46]

Let us know what happens, I curious.

[aurelius]

Worth a look?


Click HERE (http://forum.e46fanatics.com/showthread.php?t=773551) for an E46f thread that gets straight to the point re the lower oil drain hose connecting the CCV to the dipstick tube. Bottom line is it fails regularly, causes a rough idle (especially in cold weather), may save you from full CCV rehab, and is cheap/easy. Note: in addition to the part number mentioned in the DIY, there's another, insulated version of that hose. Same price as non-insulated.

Amazing how many respondents to that thread have found this hose to have disintegrated.

[BiTurbo]

Thanks for that! Ill take a look!

Worth a look?

Sure!

Let us know what happens, I curious.

The past few days have been more clement (-10) and its starting ok now. No whining sound anymore...

[aurelius]

Did you ever solve this issue? If so, do tell.