Engine misfires and dies after winter storage

[Andy1M3]

Hi all

Car is an 08 M3, manual, 100,000kms. Ran fine before storage, no issues. First start since storage - idles fine for 3-5 seconds and then misfires and dies. Can't give it gas or anything.

Ran the codes and got 27A9, P0339, C947, 5E1A. Cleared the codes, restarted it and it idled perfectly for ~10 seconds, and then started misfiring and died. Same codes showed up afterwards.

Replaced the crank position sensor. Cleared the codes, ran great for 5-10 seconds and then died. Same codes show up. Cleared the codes again, started it, ran for about 5 mins really well... it revved normally.. then slowly started stumbling and then died.

When it was running properly for the 5 mins I changed out the air filter. When I was pushing on the intake plenum to push the air filter into its position is when it really started misfiring.

Any ideas? I'm thinking about cleaning the MAF sensor... if I had a smoke machine I'd like to search for vacuum leaks.

Thanks

[amrazM]

I'd probably have a good look around for rodent damage.

[Andy1M3]

Originally Posted by amrazM

I'd probably have a good look around for rodent damage.

Lets hope not I will be changing the battery this weekend, and then I'll poke around and see what I can find.

[omgzirra_exe]

27A9 - 5E1A: usually could be battery related, maybe ground cables by the engine. or like amaraz said... wiring got chewed up.

P0339: are you DCT? there is 2 sensors you can replace, one is at the top of the bellhousing and the second one is at the bottom of the bellhousing. both different sensors though, the top sensor is RPM related, the bottom on iirc is the main crank sensor.

C947: This usually is a code from the transmission so it probably relates to the above sensors i mentioned.

[Andy1M3]

Originally Posted by omgzirra_exe

27A9 - 5E1A: usually could be battery related, maybe ground cables by the engine. or like amaraz said... wiring got chewed up.

P0339: are you DCT? there is 2 sensors you can replace, one is at the top of the bellhousing and the second one is at the bottom of the bellhousing. both different sensors though, the top sensor is RPM related, the bottom on iirc is the main crank sensor.

C947: This usually is a code from the transmission so it probably relates to the above sensors i mentioned.

Interesting. I will inspect the grounds. Anyone have a good source for location of grounds?

Car is a manual. I replaced one of the bellhousing sensors (CPS), I haven't done the second one.