Troubleshooting Codes after Engine Swap

Excers · 08-22-2019, 01:39 PM

I've got a 2011 ZCP e92 M3. Long story short spun 2 bearings and had to swap in a new engine. I am having a few codes after I installed the new engine. 2b39, 2b3a, 2b3b, 2b3c, 2b41 (Combustion misfire with cut-out cyl 5-8) The car runs perfectly with all 8 cylinders firing. I have checked over every connection over multiple times and didn’t come across anything out of place. I’ve replaced both throttle actuators with the ones off my old engine which I know are good. Using the original wiring harness and DME also. The car will idol forever and not go into limp mode until after revving it. It’ll run for a minute or 2 perfectly fine with me giving it throttle but then suddenly back into limp. When I restart the car, everything is fine, and the process repeats and she’ll idol without a problem. This is all with the car up on quickjacks, have yet to drive it knowing till immediately go into limp mode. At this point I really don’t know what else to trouble shoot. I have yet to find someone with a similar problem on the forums. If anyone has any suggestions it would be much appreciated.

Excers · 08-23-2019, 02:00 PM

Up

gingerbread · 08-25-2019, 01:14 AM

Seen something similar when installing a rebuilt motor. Ended up being a ground wire by the positive battery jump point. There is the main alternator/starter wire that bolts to a stud by the jump point, there is also other studs with power next to it. The ground wire was mistakenly connected to one on the other power studs not the correct ground stud that is further down closer to the coolant reservoir....... good luck

bigjae1976 · 08-25-2019, 10:46 AM

Have you swapped the coils to a good cylinder? Installed new spark plugs? That would be the first step. If the fault stays on the same cylinder then its likely an electrical issue.

Excers · 08-25-2019, 12:15 PM

Quote:

Originally Posted by bigjae1976

Have you swapped the coils to a good cylinder? Installed new spark plugs? That would be the first step. If the fault stays on the same cylinder then its likely an electrical issue.

Yes new plugs and can confirm all the coils work.

08-22-2019, 01:39 PM	#1
Excers Private 33 Rep 68 Posts Drives: e92 M3 Join Date: May 2019 Location: Arizona iTrader: (0)	Troubleshooting Codes after Engine Swap I've got a 2011 ZCP e92 M3. Long story short spun 2 bearings and had to swap in a new engine. I am having a few codes after I installed the new engine. 2b39, 2b3a, 2b3b, 2b3c, 2b41 (Combustion misfire with cut-out cyl 5-8) The car runs perfectly with all 8 cylinders firing. I have checked over every connection over multiple times and didn’t come across anything out of place. I’ve replaced both throttle actuators with the ones off my old engine which I know are good. Using the original wiring harness and DME also. The car will idol forever and not go into limp mode until after revving it. It’ll run for a minute or 2 perfectly fine with me giving it throttle but then suddenly back into limp. When I restart the car, everything is fine, and the process repeats and she’ll idol without a problem. This is all with the car up on quickjacks, have yet to drive it knowing till immediately go into limp mode. At this point I really don’t know what else to trouble shoot. I have yet to find someone with a similar problem on the forums. If anyone has any suggestions it would be much appreciated.
	Appreciate 0 Tweet Quote

08-23-2019, 02:00 PM	#2
Excers Private 33 Rep 68 Posts Drives: e92 M3 Join Date: May 2019 Location: Arizona iTrader: (0)	Up
	Appreciate 0 Quote

08-25-2019, 01:14 AM	#3
gingerbread Enlisted Member 51 Rep 48 Posts Drives: BMW Join Date: May 2016 Location: Canada iTrader: (0)	Seen something similar when installing a rebuilt motor. Ended up being a ground wire by the positive battery jump point. There is the main alternator/starter wire that bolts to a stud by the jump point, there is also other studs with power next to it. The ground wire was mistakenly connected to one on the other power studs not the correct ground stud that is further down closer to the coolant reservoir....... good luck
	Appreciate 0 Quote

08-25-2019, 10:46 AM	#4
bigjae1976 Major General 1570 Rep 8,075 Posts Drives: 11 E90 M3 Individual Join Date: Mar 2006 Location: Houston, TX iTrader: (22) Garage List 2004 BMW M3 [4.50] 2011 BMW E90 M3 [5.25] 2013 BMW 328i [5.00]	Have you swapped the coils to a good cylinder? Installed new spark plugs? That would be the first step. If the fault stays on the same cylinder then its likely an electrical issue. __________________ 2018 F30 320iX Melbourne Red 2011 E90 M3 Monte Carlo Blue 2004 E46 M3 Imola Red 2000 E36/7 Z3 Steel Blue
	Appreciate 0 Quote