Code 102902 rough idle

mautoservice1 · 10-18-2023, 12:21 AM

HI guys I swapped a new rebuilt motor in my f10 m5. Started car and get only 1 code 102902 air mass 2 too low. It has rough idle. Reset adaptations and learned valvetronic before i started.I already did a smoke test. No leak found. I also already swapped o2 and map sensors between banks and same code.

M5Rick · 10-18-2023, 04:41 AM

Quote:

Originally Posted by mautoservice1

HI guys I swapped a new rebuilt motor in my f10 m5. Started car and get only 1 code 102902 air mass 2 too low. It has rough idle. Reset adaptations and learned valvetronic before i started.I already did a smoke test. No leak found. I also already swapped o2 and map sensors between banks and same code.

Rebuilt LCI or pre '14 spec engine.

SmokinJoe · 10-18-2023, 11:08 PM

Make sure your injectors are coded properly if you didn’t put them back in the same holes or installed new ones. Also is it a stock rebuild?

JayDD007 · 10-29-2023, 07:44 AM

I had an air mass too low on one bank after rebuilding my s63, rough idle as well. Turned out for me one of the intermediate levers popped off the Valvetronic spring allowing only one Inkate valve to open on cylinder 5.

Hopefully this isn’t your problem because the engine has to come back out to compress the spring and replace the lever.

Luckily the valve covers come off relatively easy to check. You could also borescope the cylinders while slowly cranking the engine over by hand and checking that all valves are opening. (Set Valvetronic to max lift before doing this)

Good luck and as I said I hope this isn’t your problem

10-18-2023, 12:21 AM	#1
mautoservice1 Registered 0 Rep 1 Posts Drives: x5 e70 50i Join Date: May 2020 Location: CA iTrader: (0)	Code 102902 rough idle HI guys I swapped a new rebuilt motor in my f10 m5. Started car and get only 1 code 102902 air mass 2 too low. It has rough idle. Reset adaptations and learned valvetronic before i started.I already did a smoke test. No leak found. I also already swapped o2 and map sensors between banks and same code.
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10-18-2023, 11:08 PM	#3
SmokinJoe Private First Class 44 Rep 115 Posts Drives: 2014 M5 CP, 2019 X5 40i Join Date: Aug 2019 Location: North bay iTrader: (0)	Make sure your injectors are coded properly if you didn’t put them back in the same holes or installed new ones. Also is it a stock rebuild?
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10-29-2023, 07:44 AM	#4
JayDD007 Private First Class 105 Rep 146 Posts Drives: BMW's Join Date: Jan 2014 Location: PA iTrader: (3) Garage List 2020 G07 X7 [0.00] 2013 E70 X5 [0.00] 2003 E46 M3 [0.00] 2013 F10 M5 [0.00] 2009 E90 335ix [0.00] 2009 E90 M3 [0.00]	I had an air mass too low on one bank after rebuilding my s63, rough idle as well. Turned out for me one of the intermediate levers popped off the Valvetronic spring allowing only one Inkate valve to open on cylinder 5. Hopefully this isn’t your problem because the engine has to come back out to compress the spring and replace the lever. Luckily the valve covers come off relatively easy to check. You could also borescope the cylinders while slowly cranking the engine over by hand and checking that all valves are opening. (Set Valvetronic to max lift before doing this) Good luck and as I said I hope this isn’t your problem
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