Spark Plug Help

[PeeweeT12]

Does anyone know the correct gap for OE Spark Plugs? Stock 2012 650i. I have found several different answers. I've seen .032, and .020-.024. Chasing a misfire fire issue, so I am starting with new coils and plugs. Any other advice/assistance would be great. Car has 95k on the clock. The misfire is in Cyl 8.

[Opie55]

You'll find some discussion of narrower gaps with tuned engines, but if you just buy the correct OEM replacement NGK plugs (I'm assuming 2012 used NGKs as opposed to Bosch) they will come correctly gapped. Just install them. I'm pretty sure it's .032.

[Opie55]

Also, did you try swapping coils between cylinder 8 and another cylinder to see if the misfire follows the coil?

[PeeweeT12]

Originally Posted by Opie55

Also, did you try swapping coils between cylinder 8 and another cylinder to see if the misfire follows the coil?

I did not, with the mileage and unknown service history on the car, I figured that it would not hurt to change them all.

[Opie55]

Originally Posted by PeeweeT12

I did not, with the mileage and unknown service history on the car, I figured that it would not hurt to change them all.

You are correct it cannot hurt to replace all, and I would, but it would also tell you if you are on the right path to correct the problem before you even start.

[D'Mann]

I recently replaced all of my plugs and coils on my 2015 650i GC. It was .032 for mine, and I went with the step colder plugs to prepare for BM3...

Still waiting to do the tune, but my misfire went away with the plugs and coils.

[PeeweeT12]

Got the new plugs gapped, and installed with new coil packs. However.....I now have different codes. Any ideas?

[Opie55]

You'll get a bit more info if you look up those codes at bmwfault.codes and look under your engine. Do the codes persist if you clear them?

[PeeweeT12]

Originally Posted by Opie55

You'll get a bit more info if you look up those codes at bmwfault.codes and look under your engine. Do the codes persist if you clear them?

yes. Start up (high idle) is fine, but when it idles back down, in about 20-30 seconds, I can feel the skip, and then the light and "Drivetrain Malfunction" warning hits. Thanks for the info about bmwfault.codes. I didn't know about the site.

When reading through the service plan, it mentions about Air Supply being a cause of fault. I wonder if I put a mass air flow sensor in backwards? When I had the stock intakes out, I replaced them with ARM intakes.

[Opie55]

At least on stock intakes I doubt the sensors can be installed backwards, but I also sense you'd get a more specific code. Maybe not. But if these codes were not present before you started then it may well be something you did.