87geeinn

Bottom Line Up Front (BLUF): Engine misfires can occur frequently in the M156 engine due to failing coil(s) but may not trigger any diagnostic trouble codes (DTCs) or the "check engine" light to illuminate.

My E63 is sitting at 111k+ miles or so and I've already replaced one ignition coil based on information obtained from a DTC and check engine light warning by using the Torque mobile app. What I have noticed over the past two months or so is an apparent but very noticeable misfire developed again. I kept an eye over the symptoms as they gradually occured more frequently but wondered why I wasn't getting any DTCs. I decided to run the "Test Results" function of the Torque app and was able to pinpoint the offending coil by scrolling to the sections that break down misfire events for each cylinder. In my case, this time the coil was failing on cylinder #7 (see screenshot for reference). Note: The screenshot was taken after the car was driven a few times following the new coil install, hence the low numbers. I was sitting at like 35 misfires for the last 10 drive cycles and averaging around 5-7 for each current drive cycle. Either way, this shows how you can narrow down misfires for each individual cylinder, even if it isn't throwing any codes. I replaced the coil and all is well again. I am sure many M156s are either approaching or have surpassed the 100k mark when wear items always seem to start showing their ***. Just a helpful tidbit to keep in your mental toolbox. Cheapest place I was able to find coils was RockAuto at ~$28 not including shipping. The local parts stores are sometimes double this or more. It's good to have a spare lying around.

hayseed

iTrader: (2)

good info -- thanks

hachiroku

how do you monitor misfire? i am unable to find this on Torque Pro and my Generic Bluetooth OBD2 reader

edit:
nevermind i re-read that you went to the Test Results function of Torque.