My 2009 N12 clubman developed a smoking habit and a light rattle on start. It also started getting misfire codes (#1 first, the multiple misfires) and went into "limp home mode" on the missus once or twice. Just over 100,000 kms, so I figured it was time for a timing chain replacement and valve seals (was smoking consistent with bad valve seal symptoms).

Bought all new parts from ECStuning, BMW branded stuff, or the OE supplier.

Installation went as expected. Locked the flyweel and cams, replaced the chain, guides and tensioner with the new BMW stuff.

Did the valve seals while in there.

Get it all back together and it starts and seems to run fine. Take it for a test drive. Works fine putting around the subdivision so I think I've got it.

Get out on the main road and give it gas. At around 2000-3000 rpm, it starts to get a rattle noise, almost a knock. And it's LOUD! Like banging on the side of the engine block with a 5 lb hammer type of loud. Had a metallic sound to it, which made me terrified it was destroying itself.

Back out of throttle and it goes away.Throttle responds normally again at low settings. car runs and puts around fine.

Then the misfire codes start again, but only under harder throttle. Once of throttle, the check engine sign goes away and they show as stored codes.

I run the adaptive relearn, VVT limits and the vanos relearn. No difference, Still rattles on harder throttle and misfires.

Strange thing is light throttle to the same rpm doesn't rattle, nor does it seem to misfire. Only heavier throttle.

Only misfire codes, nothing else stored or active. Not even a knock code, which surprises me because when it rattles under throttle, it's LOUD. It actually sounds like the timing chain slapping the block or valve cover.

Pull the valve cover off and every thing looks fine. It's all tight, all torqued, vanos springs in place on followers, etc.

The Serp belt, tensioner and water pump drive pulley assembly were also changed with new BMW parts. Changed them out because this is the wife's car and didn't want them to give up on her somewhere down the road and it made sense to me to do them while I already had it apart.

What's going on here? This all makes no sense at all to me....where is this rattle and misfire code coming from?

I'm beginning to think my original misfire issue might not have been the timing chain or the oil consumption issue.

Oddly enough, the car no longer smokes, except I can make it do the occasional big blue cloud for no apparent reason. Out of nowhere, it will blow a blue cloud and then be good for a couple days, then another puff out of nowhere.

I'm begining to think this thing is possessed....

 

Alright. I think my "rattle" is the exhaust v-clamp where the header meets the flex pipe. It's got that raspy exhaust sound to it. I believe the banging was the intake piping as I found one of the mounting bolts loose and allowing the plastic resonator section to vibrate on it's aluminum mounting boss.

It only makes the rasp/rattle noise about 3 grand under load. Kinda jives with it being silent at idle and bypassing under more exhaust pressure once pushing it a bit.

Ran the car again with the scanner hooked up. Went live data on the monitor and it's a cyl #1 misfire. It works fine until you get it around 3,000 rpm and then starts accumulating misfire counts. There's no other codes other the the misfires (p0301). Once it hits around 50-60 counts it locks in the misfire code and then into limp/reduced power mode. Clear the codes and it goes back to normal running until you push it under load over about 3 grand and the misfire code starts all over again..

You have to get it up around 5 grand to get misfire in a no load condition. You will eventually get the multiple cylinder misfire code, but you only get counts on the #1 cylinder. I tried a quick and dirty de-snagging procedure of swapping the coil on #1 for the coil on #4 and vice versa. Misfire stayed with #1 cylinder so it's likely not an electrical issue. Remember I said not "likely".....swapped #1 and #4 spark plugs and misfire stayed with #1 cyl.

Compression is good. all with 5% of 160 psi.

So I'm thinking I somehow messed up the timing procedure and the cams are off juuust enough to kick it into misfire.

I ordered 6 cam bolts(two extra sets just in case I have to do them again) and a new v-band clamp with gasket. Dealer says they should all be in by tomorrow afternoon.

the smoking seems to be gone. I believe it might have been the aftermarket aluminum rocker cover I had installed. I removed it and installed the factory plastic one and it seems to have abated the tendency for the engine to blow a puff occasionally. I'm guessing the PCV isn't up to snuff on the replacement cover. I'll look more deeply into it at a later date, I just want the thing running and driving right now.

We really enjoy driving this little bugger, but it's getting harder and harder to like it......