N52K runs poorly after valve cover replacement

[clarkitect]

So decided to get this car ready for sale, including changing the valve cover/gasket with a new BMW complete valve cover. This was the second time doing this job. First time it still leaked and the dealer, who was performing the recalls on the car, claimed the cover was cracked. So I did it a second time.

I see no cracks in the old valve cover, naturally, but now the car will not run well. Starts up but hesitates, backfires, runs very poorly. Will idle and is not very responsive when trying to rev it. Flashing CEL. I checked every connection about 10 times and can’t seem to figure it out. The first time I did this job it was easy. This time is not. Only thing I did differently on this project is before I removed the valvetronic actuator I used the 4mm allen wrench to back out the shaft.

Tried hooking up my laptop to read codes but neither version of INPA I have will communicate with the car. Works fine on our E36 and E38. Not this E83. Will have to run out and buy an OBD tester today I guess.

[bmwdirtracer]

I'm really not sure why anyone does anything to the valvetronic motor. Personally, I unbolt it, it goes pop, and when I'm done I bolt it in. I've done LOTS, never had an issue.

That said, I've found a couple of things that can cause trouble, on this job:
1) Not pushing the coil plugs hard onto the coils. The little plastic levers don't do the job - you need to push, as you rotate the locking lever.
2) It's easy to pull loose a part of the gasket, as you fight to get the valvecover back into position, and if you do that, you'll have a large intake leak. I use weatherstrip adhesive to hold the gasket in place.
3) It's also easy to get an O2 sensor wire caught under the back corner of the valvecover. This causes an intake leak, AND a cut O2 sensor wire.
4) And lastly, of course, failure to securely tighten the ground wires under the 8mm nuts.....

[White94RX]

I second that. EVERY 6 cylinder valve cover gets the entire gasket inspected with a mirror and flashlight after I put the cover on.

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[clarkitect]

I'm really not sure why anyone does anything to the valvetronic motor. Personally, I unbolt it, it goes pop, and when I'm done I bolt it in. I've done LOTS, never had an issue.

That said, I've found a couple of things that can cause trouble, on this job:
1) Not pushing the coil plugs hard onto the coils. The little plastic levers don't do the job - you need to push, as you rotate the locking lever.
2) It's easy to pull loose a part of the gasket, as you fight to get the valvecover back into position, and if you do that, you'll have a large intake leak. I use weatherstrip adhesive to hold the gasket in place.
3) It's also easy to get an O2 sensor wire caught under the back corner of the valvecover. This causes an intake leak, AND a cut O2 sensor wire.
4) And lastly, of course, failure to securely tighten the ground wires under the 8mm nuts.....

I second that. EVERY 6 cylinder valve cover gets the entire gasket inspected with a mirror and flashlight after I put the cover on.

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Thanks for the replies. Not being a pro mechanic I try to be extremely methodical when I do this stuff. Coils well seated and electrical connections tight. Ground straps in and tight and I torqued the studs to 9Nm. Thoroughly inspected the gasket. Fortunately the new VC came with preinstalled gaskets that held in there pretty well. All that said I’m double checking and will need to find a smaller mirror to peer down into the spark plug wells. I can pull it apart again in less than an hour now if needed, ha.

And the only reason I loosened that valvetronic shaft was because it popped out last time I did this in such a way that made me worried about breaking something. It is mentiond in the TIS so I figured couldn’t hurt.

Thanks again.

[clarkitect]

Well. I pushed these damn coil connectors in and thought “yeah these are tight”. Guess they were not. Used this method to really seat them.


Car fired up strong. Need to drive it clear the gas out of everywhere and reset codes and see. My old OBD tester doesn’t work on this car so I’ll have to drive to autozone.

Thanks so much guys. Really appreciate the consultation.

[bmwdirtracer]

Glad you found the issue.

Because you said that TIS said to unwind the valvetronic, and I've never done that, I had to go and look it up. I don't see directions like that.....not that I follow directions, but where did you see this?

https://www.newtis.info/tisv2/a/en/e...h-lid/Ft6zjS5b

Anyway, glad it all worked out. Sorry you've had such issues with your car.

[clarkitect]

Glad you found the issue.

Because you said that TIS said to unwind the valvetronic, and I've never done that, I had to go and look it up. I don't see directions like that.....not that I follow directions, but where did you see this?

https://www.newtis.info/tisv2/a/en/e...h-lid/Ft6zjS5b

Anyway, glad it all worked out. Sorry you've had such issues with your car.

Yeah it’s been a battle. Just drove it around for a while and it goes great. Now going to sell it. I think, lol.

You know I cannot for the life of me find where it says to do that with the servo motor. I swear it was some BMW documentation but maybe it was just some DIY I found searching for answers. Hard to say. In any event I see it’s really not necessary. Hopefully this thread will help someone down the road.

[clarkitect]

Apparently Autozone and O’Reilly won’t reset codes anymore. Government conspiracy!

Here’s where I saw that about rewinding the valvetronic. I knew it was a thing.
https://www.newtis.info/tisv2/a/en/e...ear/1VnXxK6FxK

[bmwdirtracer]

How strange that there's no reference of that in the valve cover instructions. I've never had an issue; never known any other techs to do that either. I just hold the motor in place while I undo the screws, then let it "pop". I'll check with a few more techs I trust....

White 94Rx, are you listening? Do you unscrew this?

[White94RX]

Nope, never. Unscrew it, let it pop out. Reinstall, tighten screws. Done.