Lotus99

This is a cross post from the wagon forum, but since it's not specific to wagons probably, I thought I'd post here to get more action...

Our wagon is a 2010, with only 30,000 miles on it at the moment, and when we start her up, on cold starts, for the first minute the car vibrates quite a bit lately. This is before we drive off, so it has nothing to do with tires.

It seems to almost go away when the car is warmed up though, like after a minute of idling, or when the engine is already warm and you start it up. It's still there, but very faint. I wouldn't describe it as a fast shudder, but as if the vibrations were in a wave format, like something that spins and at the top of every movement, every time it vibrates. It's the whole car, and you can feel it in the seat, not thru the steering wheel.

Wonder what it could be?

plowery21

I have experienced a rough low idle at start..and I can usually watch the tach rpms raise as the engine adjusts. I have always attributed to fuel quality with the amount of ethanol now added. Happens for the first min, but as soon as I put it in gear and press the peddle it seems to be fine or progressively get better.

May not be the same thing your speaking of, but thought I would share just in case. Good luck.

Lotus99

Odd thing is I have a 335, so same engine in that car, with about the same mileage on it too, and it doesn't exhibit any of these issues. And they both get the same gas (91) though usually from different stations. What's happening is fairly recent too, last couple of months I'd say.

It wouldn't be related to bushings I suppose, or anything like that?

The fact that it goes away after a minute is odd too... I tried to depress the gas pedal manually and keep the RPM's at 1000 once the engine's warmed up, but that doesn't replicate the vibrations. But it's still there faintly during idle even when warmed up.

Lotus99

Update: Today I went in for the vibrations, and they said it wasn't the fuel injectors in their opinion, but rather the spark plugs and carbon buildup! So I got a fresh set of plugs, plus a walnut blasting to boot, and we'll see how she does in the next few days. Hope that's it!

Booyaazaa

Nice. I had a similar issue and the dealer had to replace all 6 of my injectors. My startup and idle are now smooth as silk.

stamd1

I have a 2009 535xi with 58,000 miles. I had the same problem and the check engine light came on. First time at the dealer they replaced the spark plugs which were due to be replaced and one bank of injectors that were found faulty. Less than 5000 miles later the same vibration at start up and the check engine light came back on. They found the second bank of injectors at fault and replaced them. The vibration only occurred during cold engine starts. I would stop the engine and restart to stop the vibration. Driveability was never affected although I did noticed a slight drop in mileage each time.

Lotus99

I never got a check engine light and when they scanned the car, he said there weren't any codes.

Booyaazaa, did you get a check engine light or do you know if there were codes?

I asked them if the injectors could have been the cause, but they seemed confident they're not and it's the carbon buildup. I suppose in the next few days if I still get a rough cold start, it might tell me if it's more than that or not...

Booyaazaa

The first time I took it in I didn't have a cel and they couldn't replicate the problem. The next time, after my car sat outside on a cold day for 11 hours, I started my car, was letting it idle for about a minute my rpm's dropped, idle got rough and my cel came on. When I pulled the codes it showed fault codes for multiple misfires on multiple cylinders. When I took it backto the dealer, even though my cel light was off, the dealer pulled the fault codes and found that both injector banks were done. They usually won't do anything unless there is a fault code to start the repair process. It could be a few different things bad coils, plugs, injectors, and carbon buildup. I too thought carbon build up but it was injectors for me. Now my car starts right up and the idle is smooth as silk.

Lotus99

Yeah, I know they don't do things usually without codes, but the injectors, now that I think of it, were part of a recall a year or so ago, and the only way to confirm they weren't affected, is to pull them out and check them AFAIK. I'll double check with them if they've done that on my car.

EDIT - Looked up the bulletin, and it's only for cars produced up to end of 2008 that were affected.
.

M603

I had to same problem, for me it was the coils. I changed all 6 of them and the vibrations went away at cold starts.