Strange Major power loss episode

[Benderloch]

Hello All

We were up north back in September on a very hot day. We parked up for an hour and returned to our E86 Coupe it started fine but it immediately it became apparent it was only running on,probably 4cylinders. The engine management light was on. I continued for a few miles then stopped and switched off for a while to see if that might reset things. This made no difference. At this point the car started emitting clouds of white smoke that I assumed was unburnt fuel. This also coincided with the low fuel light coming on. After another couple of stops and starts and a tank of fuel I was back to 6 cylinders. We were up at Pennan (Local Hero fame) so 1.5 hours to get home.
The car was perfect for the journey home.
I read the fault codes when I got home and found misfires on 4, 5 and 6 plus fault on pre-cat sensor. I cleared the errors and its been perfect since. The car was in at the Indy I use last week for its MOT and they checked the engine over and couldn't find any issues.
I think this issue was probably due to high temperature and low fuel. Has anyone experienced anything similar?

Thanks.

 

[Trav]

I have only experienced something similar on a 6 cylinder diesel BMW with a single injector failure. It shut down 3 cylinders and gave codes for all 3. But the fault was traced to a single faulty injector. I was told that the Bosch engine management (I am saying Bosch but that may also be a bluff) shut down 3 as it was only designed to detect 3 and 3. I am not sure if that is true or not. Even though I remember seeing 3 codes. The guy at BMW just tested the old fashioned way with a multimeter and found the faulty single unit. After that the car was fine.
Its something to do with the way the voltage is supplied to 1,2,3 separate to 4,5,6 the unit then individually provides the ground. So the engine management can only detect that it came from either 1.2.3 or 4.5.6. I think that was what was said anyway.

 

[Rockhopper]

Sounds like it’s had diesel in it