PDA

View Full Version : 05 525i rough idle

pookie
10-29-2014, 08:44 AM
Guys,

Still helping a buddy with his car. It has been having a rough idle for some time. While driving everything is fine, but at idle upon startup it gets lumpy (for lack of a better term). Also, when pulling into a parking spot, prior to shifting into park, or even while in park, it also gets lumpy and almost hunts for the right idle speed. Last time he brought it over I was able to track down what I thought was a slight air leak at the crank case valve breather hose. He replaced the hose and the idle smoothed out for awhile but after a month is now back to the regular lump.

I don't know enough about these cars, so I am posting here. I'm hoping you guys can tell me what else it might be. A sensor of some sort maybe?

Thanks
N0tt0N
10-29-2014, 09:38 AM
Interested as well. One of the reasons I was asking about a service place besides the valve noise is a hunting idle.
86911TLCAB
10-31-2014, 11:13 AM
Ryan, did you pull the idle control valve and clean it up? looks just like the one on your 3.2...pull it and use some carb cleaner to clean it out real good as well as the associated hoses...could be clogged and not moving freely.
jerome951
10-31-2014, 12:57 PM
How many miles on the car? On my '06 330i, a new set of plugs cured a lumpy idle @ 60k miles.
Trak Ratt
11-02-2014, 11:11 AM
Vacuum leak. Like Lupus it's one of the last things that considered.
pookie
11-03-2014, 12:52 PM
TR- we checked for vacuum leaks and that's how we found the breather hose.

Jerome- Current mileage is 125k and the plugs were done around 5k ago. (Could the plugs be gapped incorrectly and causing it? He did the plugs on his own.)

Tito- no idea on the ICV. I will look up its location and check it when he brings the car over.
Intubator
11-03-2014, 06:29 PM
Bad coolant Temp sensor??
Clarke
11-05-2014, 05:58 PM
I'm going to assume that since you didn't mention it, there is no CEL on, or codes stored. At this mileage, I would be checking the DISA valve to make sure that it is intact. You should also be looking at the CCVV and it's associated hoses. The oil return hose (goes from the bottom of the CCVV to the dip stick tube. Also check the intake boots. If the idle issue is more obvious when ambient temps are low, it could be VANOS seals.