328i odd vibration for a second and rpm drop

car: 2007 328i E92

Hey all,


I'm stuck with this weird problem I just started experiencing right after I replaced all my brake pads and changed the oil (to mobil 1 5w30 full syn) Even though this maintenance was performed, I can't see ANY RELATION whatsoever to the problem.

The problem is that when the car is idling, there is a vibration (which is also audible) of the engine and slight rpm drop of maybe 100-200 all within a second, maximum two seconds and then it returns to normal.

I cannot consistently recreate the problem, it comes and goes, but it seems to happen more when I "do" something while in idle like switching to D or R and holding the brake, and or steer in place. Or simply driving and then stopping at a stop light while holding the brake.

what could this possibly be?

Originally Posted by event3horizon

I'm stuck with this weird problem I just started experiencing right after I replaced all my brake pads and changed the oil (to mobil 1 5w30 full syn) Even though this maintenance was performed, I can't see ANY RELATION whatsoever to the problem.

The problem is that when the car is idling, there is a vibration (which is also audible) of the engine and slight rpm drop of maybe 100-200 all within a second, maximum two seconds and then it returns to normal.

I cannot consistently recreate the problem, it comes and goes, but it seems to happen more when I "do" something while in idle like switching to D or R and holding the brake, and or steer in place. Or simply driving and then stopping at a stop light while holding the brake.

What's been done to the engine so far?

First thing to do: Check codes

.

Originally Posted by CALWATERBOY

What's been done to the engine so far?

First thing to do: Check codes

.

Not much to the engine that I can remember of except a few oil changes. The car has about 50K miles and there are no codes at all.

Originally Posted by event3horizon

Not much to the engine that I can remember of except a few oil changes. The car has about 50K miles and there are no codes at all.

How was that checked?

Originally Posted by CALWATERBOY

How was that checked?

I don't see any on the instrument cluster? I guess there are hidden codes too since you're asking eh?

Originally Posted by event3horizon

I don't see any on the instrument cluster? I guess there are hidden codes too since you're asking eh?

Should have a look - very revealing.

Might be something to do with the gas in the tank. If it continues over a few tank fulls, then start looking elsewhere.

Originally Posted by DougN

Might be something to do with the gas in the tank. If it continues over a few tank fulls, then start looking elsewhere.

Thought about it. I'm using 93 octane from sunoco most of the time. I just haven't had this issue pop up until recently.

Alright but I see no codes in the check control area or anything. No check engine light. But if there are codes that can be triggered in a hidden fashion with no indication, and can only be read by a tool, then that seems pretty stupid. But just my rant.

Anyway, I did more testing and it doesn't seem to happen when a/c is off. When I switched a/c off another oddity occurred in that there is a DEEP low frequency RUMBLE that almost hurts my ears when the ac is off and I am in D or R. This goes away when the a/c is on. So bizarre.

Also I noticed when the problem happens, the car just wants to lunge forward. It almost seems like it is not caused by the engine at all but maybe transmission.

I'm a bit new to BMW and so far not impressed mechanical wise though the interior and exterior design quality in this car is world class. I've been in a few Benzes where i can neither hear the engine, nor rumbles nor vibrations. They're smooth as butter.

Originally Posted by event3horizon

AI'm a bit new to BMW and so far not impressed mechanical wise though the interior and exterior design quality in this car is world class. I've been in a few Benzes where i can neither hear the engine, nor rumbles nor vibrations. They're smooth as butter.

The stroke from Munich's a touch bugs-in-the-teeth, but Germans have always been hard asses, some ways. A manly feel.

Check codes by hookin' up an OBD II cable - please DO click the link.

Search not a bad idea at all. Lots to see & learn, but your mission here is to list all codes thrown so we can see what the car sees. Yup, some are hidden, the better to inform your friendly BMW tech rather than doing maint your bad self.

Some SA's get kinda touchy about OBD II scanners. Paranoia strikes deep; don't like an overly informed client. Draw yer own conclusions!
_____________

Which MB's do you like?

Thanks cal.

I think I made a slight breakthrough but not sure. I think it was my dirty air filter causing all this. Annoyingly, I had to remove the entire assembly to take it out. I had the filter out and drove around and engine seems to run noticeably smoother. I tried to recreate original problem but couldn't. It could be this. I'll do more driving tomorrow and report back.

still no go unfortunately. Still happens. I guess i'm just taking it to the dealer. I still have powertrain warranty so we'll see.

i am having the same problem on my car. When I took it to the dealer they said it was the coil. I have 80000 miles on it now. Anyway it happens mostly when at a stop light. I know exactly what you are feeling. I thought it was gas because once i filled up with some Exxon (using shell always but needed gas and had to stop at the Exxon) and it got worse. I also had washed it and someone said it could be the moisture. let me know what you figure out.
Oh and they wanted 850 to change the coils and plugs.

interesting. One thing I can tell you is that it has become very rare now since changing my air filter.

Just an update this problem's been back and even worse than before. I wonder if that recall thing is any relation to this.

Also I'm not sure if this is a misfire or something similar. I have no codes, no lights. Just freakin confusing.

Finally have a video. Here it is in all its horrendous glory. Is this a misfire?? When the problem happens, the brake is being pressed and the A/C is on. Does not happen when A/C is off. Happens in D and R. In this video, it is in R when it happens.
Have your volume up and listen carefully.

Finally had time to give her to the stealership. Luckily I have extended warranty. They didn't know EXACTLY what the problem was but did whole bunch of things (probably to rip off the warranty company) so finally the problem is fixed. It idles a whooole lot smoother and no jolts:

-Replaced water pump, fill and bleed cooling system <-- why they did this, have no idea. They claimed there was a code diag.
-Swap VANOS solenoids <-- no idea what this is but could've actually been the problem
-Trans Fluid leak: Replace transmission sealing sleeve, replace mech sealing sleeve and trans pan.
-Suspension concern: Replace front thrust rod bushings

I can safely say definitely the VANOS solenoids caused this:

VANOS is a combined hydraulic and mechanical camshaft control device managed by the car's DME engine management system. The VANOS system is based on a discrete adjustment mechanism that can modify the position of the intake camshaft versus the crankshaft. Double-VANOS adds continuous adjustability to the intake and exhaust camshafts.

VANOS operates on the intake camshaft in accordance with engine speed and accelerator pedal position. At the lower end of the engine-speed scale, the intake valves are opened later, which improves idling quality and smoothness. At moderate engine speeds, the intake valves open much earlier, which boosts torque and permits exhaust gas re-circulation inside the combustion chambers, reducing fuel consumption and exhaust emissions. Finally, at high engine speeds, intake valve opening is once again delayed, so that full power can be developed. VANOS significantly enhances emission management, increases output and torque, and offers better idling quality and fuel economy.

Here's mine:

https://www.youtube.com/watch?featur...&v=D5_ufSBlurM

I haven't had time to take it in yet, but you think its vanos? I did some research and it matches the symptoms of an eccentric shaft sensor. Do you know which vanos solenoid was replaced?

Originally Posted by ptrcd003

Here's mine:

https://www.youtube.com/watch?featur...&v=D5_ufSBlurM

I haven't had time to take it in yet, but you think its vanos? I did some research and it matches the symptoms of an eccentric shaft sensor. Do you know which vanos solenoid was replaced?

Wow your RPM oscillates vigorously there. I didn't have that many frequent oscillations as you may have seen in my video. Of course I cannot say if the solenoid is a problem on yours but If you have someone do a code check first for any other problems then you should consider it.

On the repair sheet it said Solenoids with a plural so I guess both of them, assuming that there is two total.

OK NEVERMIND.. again.. I'm tired of this but the problem is still present. For some reason when I tested at night there wasn't a problem but maybe because the car didn't warm up. Today driving around longer, the problem is back. Back to the dealer, sigh.

hello event3horizon i have the same problem with my rpms as you posted in your video I seen that the dealer changed you vanos sineloids but the problem came back. I was wondering if you were able to fix the problem and if so what did you need to fix I hope you could help out

YES!! I was just about to post back soon. After over a week they had the car (second time), they first thought or had computer code that coil 3 was faulty, so they replaced it.. but the problem came back. Finally, they replaced ALL the coil packs and problem is gone for good!! Of course, Mike posted above and was right about the coils, but due to dealer incompetence they decided to focus on other issues thinking it will fix whatever my complaint was. What an annoyance this was but I'm glad it's fixed. Probably crappy low grade coils used sadly.

Thanks event2horizon i didnt know what partts to order was thinking vanos sineloids but not any more found coils OEm on ebay all six for $230. Do you think I should change the spark plugs too? I got 79,532 miles