Idle problems driving me nuts!
 

First off, Thanks in advance...I've spent hours and hours searching not only this forum, but other bmw forums and even as desperate as googling. I could find hundreds of people w/ similar problems but no particular fix.

I've got a 2006 4.4i w/ 61k miles on it. I bought it in june w/ 54 miles. It quickly developed a low rough idle that would studder under acceleration from a stop. I replaced the MAF and that solved the studdering and problems under acceleration.

But the idle is very rough and shakes the whole cabin. It happens in drive at a stop, in park, reverse and neutral. Once under way it seems fine, no sputtering or any noticeable problems. When the A/C is (no matter how low) the idle increases by about 100 rpm or so and the vibrations get MUCH better. Turn the ac off and it immediately drops back down to about 525 rpm. I've also noticed that I can give it a hint of gas to bring the rpms up by about 75-100 and it's much much smoother... this fix works in park, drive, whatever.

So in the past month or so I've replaced the MAF, replaced the air filter, changed engine oil and filter, ran several fuel system cleaners, always use chevron or shell 91....

Any ideas as to what else it could be ? is 525 rpm too low ? It seems to me it is simply idling too low per the computer.

How do I check for a bad engine mount(s) ? I don't think this is the problem though because a few rpm increase and the problem goes away ... can anyone advise ?

Spark plugs and fuel filter... I was going to change, but upon further research it is quite unlikely the plugs went bad at 55k miles. The fuel filter likely isn't the culprit at this mileage and if it was plugged it's effects would be felt on fuel throttle and higher fuel demands, which is not the case.

I've checked all the hose I can and don't see where there could be a vacuum leak...

The battery also seems to be in tip top shape and is an OEM bmw battery that looks like it is new.

I'm at a loss and it's getting really frustrating... any advice or insight from people with similar problems is much appreciated. I've found many incidents of similar problems but no culprit.

I am so glad someone else is as frustrated as I am with this problem. I have a 2006 4.8is with 54k miles. Hopefully someone can help us out.

You know man, I have the same model and now at 82K miles... my car has a little rough idle but nothing as worse as you are saying and it just drives rough.. Mine is a CPO and BMW techs have checked it out many times and they say - this is normal for E53 blah blah and they are loud and rough to drive and idle... So i am at a loss as well. I test drove an E70 and whoa loved that baby, unfortunately still too expensive for my wallet. Good luck finding the root cause

This is exactly why I have not taken in to a tech! I've read about everyone's experience w/ tech's telling them it's normal, if it doesn't throw a code it's ok, etc. It's definitely not ok and it makes my damn feet and legs irritated when I'm stopped in traffic or at red lights... I sure hope someone can help me because i really enjoy the combination of utility and handling of this thing... but I am not trying to replace engine mounts, spark plugs, battery, etc trying to chase down a solution.

Very good Drew,
Do not start chasing the problem because it won't solve anything. There are a lot of people on here; and I have done it myself, told the forum here, left and said "Damn, now I'm chasing a damn problem by throwing parts at it!"

Anyways, as far as the rough idle, it sounds like it has to do with the X breathing or emmissions. I would check to see the throttle body and look at that butterfly plate. If it is covered in carbon, that plate may have a hard time properly opening and closing. Carbon may be covering the plate, blocking air flow when the motor is in idle. If it is covered, hit it with throttle cleaner. I've done it on my X 4 times and no problems. You might trigger a CEL but it goes away after a few hours of driving. And emission wise, check the ERG valve a check to see if the valve is sticking, de to carbon build up. Anyone want to concur?

At least these things don't cost any money, well besides the $6 on the cleaner, and $9 for a 6 pack of bud???

Hey thanks, this is exactly the feedback and productive suggestions I was looking for! I forgot to mention I actually cleaned the throttle body 2 nights ago. It really really clean to begin with... The ERG valve I'm not familiar with. I'll have to look that up and check it immediately. Thanks a lot.

I had the same problem. Started using Techron - every other tankfull - no other service. Rough idle went away.

--2006 4.4i

I ran a tank full of techron followed by a tank of seafoam my last 2 tanks... and in total I've probably ran about 5 or 6 cleaners through... I'm not against throwing another one in there if it fixed yours. You had the same problem where the ac would fix the rough idle as well ? Am I crazy thinking the idle at 525 is just too low ? Thanks.

It appears only the 3.0D has the EGR... are you referring to something else I should check/clean ? Thanks

UHG you're right, I'm having another brain fart, its not an EGR system... I'm trying to find it on the diagrams what I am talking about. Ill get back to you.

Just a thought: clean the Idle Control Valve and throttle body.

i too also have the same problem with my 3.0i 2004 11200 miles on the clock. somehow i think the transmission is the culprit of all of this. In my car Neutral / Reverse / and Park don't trigger the irritating idle but as soon as i move the shift to Drive the car begins to vibrate. Now im thinking the transfer case? maybe / tranny itself? maybe I really just hope that someone would point me to a solution.

Throttle body has been cleaned and I'd love some advice on the idle control valve ... Is there one on the 4.4i ? I searched on if leaning would help and how to and it all related to the 3.0 and I couldn't seem to find where it is on realoem.com

don't know where and if theres an ICV on a 4.4 but i've cleaned mine and nothing no difference in idle.

Turning on the AC would boost the idle speed a little and smooth the idle. I believe my idle is at about 700 or so.

Thanks... Yea my idle is barely over 500. When I turn the AC on its jumps to about 650 or so and gets a lot smoother. Can you manually raise the idle ? Possibly an Indy or dealer could just override and turn the idle up a little ?

the throttle body has no effect on this vehicle when it comes to idling, it is solely used for start up, failsafe and to maintain a 50mbar vaccum for emissions.

the idle on the ME9 engine management can be increased by 50rpms, a service function is available to do so

Thanks... by 'a service function is available' i'm assumming this is something that only a dealer can accommodate ?

I hope they will help me out, I have a feeling I'm going to get the no codes, no problems rant...

basically anyone with g1 software could do it. i pretty sure but i dont know who has what so the dealer is a likely option and if you do figure this out please report back.

Hi guys I have the same problem as Drew my 4.4 just about idles around 450-550 rpm, with the AC on it improves the rpms but sometimes cuts out and then restarts after I've left the ignition on for a few seconds.
Really starting to get to me now so i think it will be of to my local indy to see if they can find anything.

Stay posted guys, mine is getting even worse and I don't think turning the idle up 50rpms will alleviate the problem anymore ... And I want to know what's wrong, not slap a bandaid over it. I'll be doing new plugs and see if that helps ... Only 62k miles on these oe's but you never know. Keep you posted and let me know any other suggestions. My brothers muscle cars shake less at idle!

Since you mention a stumble I'm going to go with some possible issues.

1) Torque converter -- when driving from a dead stop in a normal way you will feel a very strong shaking right after the upshift. Put the trans in Sport Mode and it will go away.

2) Rough Idle/Low RPM's you have a ignition issue. Check Coil Packs and plugs. The low idle is a possible vacuum leak.

I had these same problems and mine was multiple coil pack and plug failures from oil leaks around the valve covers. I think the wild card here is that I was getting a flashing check engine light showing me a misfire after a while. Prior to when this was just a nuisance it never flashed just ran horribly. I had some hoses that were dry rotting. Replaced those and finally worked out all of the ignition issues and the idle acts right now.

Thanks. I don't think it's a torque converter issue as I have none of those symptoms. I'm planning on doing new plugs asap and I'll let you know what I find... hope it's that simple. I've looked and looked for vacuum leaks but everything looks good. Never a check engine light...

One more thing is the oil separator hoses behind the intake. One plugs in to the driver side valve cover and the hoses run back down behind the center behind the intake.

There are two of them around 3/4" OD. They are prone to crack and cause this as well. I had to replace mine. They will look great from the front but to the best of your ability check them on the bottom side and back. Esp where the one connects on the driver side valve cover.

Also the next chance you get the truck in total darkness open the hood with the top engine cover off. Be careful not to chop your fingers off on the fan since your in the dark (lol) and look at the coil packs. Once your eyes adjust you will be able to see a little bit of flickering through the boots. It should be *very* faint.. just a flicker. All of these should look the same. If you see one that is not really doing much at idle compared to the others then that is your problem.

You could still have a screwed up plug under the pack though. Also, if you see one or more packs that the arc is visible outside that is a failure as well. I had a couple that were arcing out of the pack on to the valve covers. At times you could even hear it pop.

Will check this out too... I don't recall seeing these but i'll pull the covers and check again tonight... any chance you could point these out to me ?

RealOEM.com * Diagram Selection

Thanks, I'll check this as well.

Ok... I've got the engine cover off, for about the 10th time in the last 2 months and this is so frustrating.

The CCV or oil separator hoses... I can't see or feel them... and I'm searching online but all I find is 3.0 and M62 pictures... is it different on my N62 2006 ? Does anyone have pictures ?

Any help is appreciated!

Ok. Well I can't find any hoses behind the engine as everyone suggested. I did find two ccv vent hoses on the front in good condition... Unfortunately I broke the connector on one and it should be here Monday to fix it. Pulled the coils and a plug and they are super clean. Plugs look like they are burning great. Not going to replace ...

The fact that turning the AC on fixes or significantly improve it make me and my Audi mechanic buddy think it's not a vacuum problem. Maybe a coil going bad... But no codes. I already replaced the MAF and that wasn't it so im really considering trading in as it needs tires, alignment and brakes shortly and the nav screen is going out. I can't handle fixing all that an still having this worsening idle problem.

Any other ideas ?

Drew any luck with the idle problem?

I think TwinTurboGTR is referring to the Secondary Air System. See attachment. Stuck open Non-return valves could allow exhaust gas to get sent to your secondary air pump, but I wouldn't expect this to cause rough idle problems.

I would spend the $35 and review all the SIBs for Group 11 (Engine) and Group 12 (Engine Electrical) on bmwtechinfo.com

Great info, but how does one test/clean/inspect them?

You could disconnect the air pump after starting a cold engine and feel for the blower to output air and simultaneously there should be no exhaust gas coming from the opposite end.

This graphic is from the E65 training literature (also from bmwtechinfo.com), but it should be similar for the E53 X5 with the N62B44 engine.

Ok, this is good stuff. I am guessing since my engine is 4.8, but still N62 this would also apply.

Seems like there is a lot of tubing there that could be leaking. I am going to check this out tonight.

So let me get this straight.
So if I disconnect the hoses at number 5 or at both number 4s, I should get air coming from the blower, but then I should also not get exhaust from same hoses/valves telling me if the check valves are functioning.

I think I got it. I just hope I can get to that pump easy enough without removing the entire intake.

Will this throw a check engine code? If yes, I need to go get my scanner back from my friend before doing this.

On a second note, can I test those check valves off the car. I have an air compressor I can use to blow through it. I am just curious how much that valve can handle. I am guessing it is not much PSI going through there.

Thank ripp.

Ok ripp. so this was a fail. I should have checked RealOem before standing over my engine for over an hour. I don't seem to have this. My engine is 4.8. Any other advise? Thanks.

I didn't know you had a 4.8is and hence a N62B48 engine. You are correct, no secondary air system.

Assuming you have rough idle, I'd still read all the SIB's to see if there may be one pertaining to your car. Then I'd have all the fault codes pulled.

OK. I figure you don't have it, so I guess I might have to do this TIS thing.

I have a 2006 4.4 with the same symptoms. Idle around 525 with vibrations. I have only owned the car for a month so I don't have much to compare to (was it always this way?) but it just seems rougher than it should be (rougher than my 5.7 sequoia) and with a little extra rpm it smooths right out. If anyone found solutions. Please send an update.

Idle fluctuation
 

Changed wiring and MAF, improved but still had a leak.
When removing the oil cap with car running you should hear the air entering otherwise you have a leak. After spraying the intake with carb cleaner no change, meaning no leak in this part. Finally, the shaft seal gave up and sprayed oil on the belt, that grew bigger and came out. After replacing the Shaft seal problem solved! Hope this helps.

Sounds like a vacuum leak problem to me.

Sorry if this has already been suggested, I didn't read the entire thread.

Vacumm
 

That is what I am saying, it was vacuum, but ...is there a protocol to determine that it was the shaft seal??? I discover it by chance

Which shaft seal are you talking about. Where on the engine?

On the front

is this shaft seal on the front in relation to a valvetronic problem causing the vibration? Mine started idling a bit rough and my mech said he's seen a rash of 5 people over last 2 months come in with exact same problem I'm finding with my x5. cel showa no exact problem, just "misfire" on cyl 6, 7 & 8.

hey I have 2005 4.4 x5 same problems. what shaft seal are you talking about , can some one please specify. and were there any other solution ?