Engine rattling only at high rpm

[Jaymes]

Been trying to search for a similar problem but with no luck. I have a 2006 330ci with about 112k miles on it. So as the title says, whenever I take the car up to the higher rpms, I will hear a spinning rattle which will go away when I release my foot from the gas pedal and will speed up if I continue to apply gas.

What the car will do after woulds is pop a check engine light on and begin to misfire. The car misfires until I turn the car off but immediately after the start up, the CEL and the misfire will go away.

Any possible ideas on what it can be?? Going to take the car to the shop tomorrow to see if the code(s) were stored or not but until then would like to have an idea of what I'm dealing with.

Thank you in advance!

[Dave1027]

It will have codes to help determine the cause. Don't even start guessing till you have the codes.

[Jaymes]

Took the car to get the codes scanned at a shop.

Mechanic told me

Misfire cylinder 1
Misfire cylinder 2
O2 sensor pre cat
And a fuel system code.

Once the code is removed, the car runs normally and the misfire is only introduced when I take the car close to the redline. I asked if it could be the O2 sensor but he told me that he doesn't know where to start as it could be anything as that may not be it.

Recently changed on the car about a month ago was the crankshaft position sensor, fuel pump, fuel filter, fuel pump relay, & spark plugs. Suggestions?

[TonyAngel]

Did you take it to a BMW guy or a shop that used a generic OBD scanner? Running a generic scan that returns "P" codes can be misleading. If you haven't you should get a scan run using BMW specific software. A rattle coming from the engine bay could be something as simple as a DISA valve and may play hell with the air flow inside the intake causing some of the problems you're having. I'm no tech and am relatively new to BMWs myself, but what you're describing in terms of the noise in conjunction with the faults you're getting sounds like it could be a DISA. A piece could have broken off and might be wedged someplace.

[Jaymes]

Sorry for the late reply, finally had the time to work on the car.

The car was only taken to an Indy with a generic scanner. So that was pretty much useless. I plan to replicate the misfire and take it to a BMW specialized shop this weekend.

Until then, I had the time this weekend to remove the disa & inspect it. Valve worked properly and everything was intact.

Car continues to chatter only above 5k rpm and will continue if I remain to give throttle. If I release the pedal, the rattle will go away. If I stay at that rpm and cause the rattle long enough, the misfire will happen. Not to sure if that's a ping?

[Jaymes]

Bump. Problem still ongoing, please help. Rattles only at high rpm, followed by a misfire (which self clears)

Finally came around to really look into the car. Took the DISA out and it looked to be in good condition (metal pin still in place & the air vacuum system was in proper function). I also removed & inspected the upper and lower boots for cracks (none). Called an independent and he advised me to look at my coils and possibly replace them. Does that sound likely?

[Jaymes]

Car does seem to feel like theres a substantial loss of power and my mpg is averaging at 13.5 in the city. Ignition coils seem to follow suit with those symptoms but I dont know if it can cause a ping at high rpms

[Eaglesail]

So is there a scanner we can buy that rivals the BMW dealership? If we have now to question an friendly indy for code reading integrity...this seems an issue for all...yes?

[TonyAngel]

That sound you're describing sounds like a DISA valve could be the problem. You said you checked it though. I'm not real familiar with the E46 330, but the E90 330 has two DISA valves. Are you sure that you only have one?

On the other hand, if it was a DISA, I would imagine that it would rattle all of the time.

Are you sure that it only does it at high RPM? I mean, are you sure that it isn't doing it all of the time and just gets a lot louder at high rpm?

[TonyAngel]

Eaglesail, I believe your question was answered in the thread that you posted. The most comprehensive tool that we can have is to get a cable and a suite of software (with INPA, ISTA, etc.) and install it on a laptop. This will allow you to read present codes and stored codes, do coding of new components, etc. The handiest tool is a handheld unit with BMW specific software. I use a Foxwell NT510 (I believe it is). It isn't as capable as a laptop and software, but it will read and clear codes and do coding and adaptations. Of course, there are several other units that will do this as well, such as the Schwaben unit.