BMW 525i, 2007, E60, N52, Miles: 109k



Alright folks I heard there were some smart people here, please help me figure this one out.
My idle is bad when the AC is on. Usually happens when I first start the car for the day or at a stop. The RPMs stagger and the engine shakes and vibrates pretty bad. This has been happening for about 6 months now and i've done the following: Change spark plugs, coils, Checked for vacuum leaks, changed vanos, cleaned MAF, change air filter, oil, added AC freon. What am I missing here? The dealer has already robbed me of over 1k and the problem still persists. The dealer says either they can't replicate or to change my spark plugs. I've changed my spark plugs twice. Bottom line is i'm fed up with this issue and I can't rely on the dealer to fix since "I'm getting no codes". Truth is i love my 5series and want to keep it and I would like to fix this before I'm stuck onside of the road in hot ass Texas. Thanks for your help.

 

With no codes there is not much you or the dealer can do. It seems you have checked everything I would have checked.

The stealership will continue to troubleshoot as long as you are willing to spend $$$ but they will not figure it out without a code. They probably will tell you you need a reman engine that would for sure work. LOL

Keep us posted if you figure it out

 

does your idle increase when you turn on your AC? is it dropping? is there a weird sound coming from the engine bay when the AC is on? if its shaking and so forth and you turn off your AC will the shaking stop?

 

The idle increases and decreases, it staggers about 200 RPM up and Down. The only weird noise I hear is when the AC is on low. There is a faint "humming" noise coming from the AC vent. And Yes.. The shaking does stop when the AC is off.

 

Has dealer or you removed AC belt and checked compressor pulley?
That's where I would start now.

 

+1 on cmyachtie's recommendation except that he mentioned the word "dealer". I hate that word. Get to a good indy as you'll need a special tool to remove the AC belt because our engines dont have a belt tensioner for the AC belt. and see what happens. Also the shaking RPM 200 up/down does it happen around the idle value of 500? or is the car increasing idle value to around 700 then starting to shake? in general the problem you're having is 95% from the compressor though i would recommend that you have your car coded to increase RPM idle value when the AC is on. That will make things even smoother. That can be done with ISTA/P. NCSExpert can probably do that but i dont know which values can change that.

 

It happens generally around the 500 RPM area or Normal idle. It also has a faint humming noise while AC is on. the weird thing is it does the same idle jumping even with AC off as it did this morning. Is that also an compressor/pulley issue?

here is a video of my drama.. this link will break after 1 day. if you didn't catch it let me know I'll repost.

http://jmp.sh/CvPpH7p

 

sorry couldn't get to the post in time. Your saying there is an idle jump with ac off too. Then no your AC has nothing to do with it. you said the shaking stops with the ac off before. is it a different kind of shake?

 

Yes. It does it even with AC off. Always when the car is initially started for the day, but throughout the day it doesn't do it. Did you see the video in my last post?

 

Just watched the video. Thats a serious erratic idle. First step is get to a good indy. Dont go to the dealer anymore. Show him your issue. If you inclined the first step in your process is to isolate the problem. try running with the AC belt removed see if the engine sound is smooth if the idle changes and so forth. then at least you'll know if this is an AC problem or an engine problem.