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View Full Version : 530i running rough



skylinergtr
06-10-2010, 12:32 AM
I finally started my car. It started immediately, however it has been running rough. Total running time of over an hour. I've gone through the sensors, connections, fuel injectors, plugs, coils, maf, o2 sensors, etc. I did the intake again today and it is still running rough. I am grabbing codes misfiring on basically one bank (cyl 5,6,7,8) and o2 sensor faults (from the misfire). Im leaning towards the ICV but it was fully functional before i started working on it. I pulled it out and cleaned it too (even though it was clean to begin with). I used to think i was pretty good at troubleshooting with motor but im confused on why its running rough.. I've also sprayed intake cleaner all over and found no leaks. Any suggestions?

TIA

Binjammin
06-10-2010, 01:34 AM
o2 sensors connected backwards?

skylinergtr
06-10-2010, 01:38 AM
o2 sensors connected backwards?

o2 sensors have not been disconnected. They were replaced maybe a year ago with not many miles on them. OE bosch. I checked the connection and they are fine. The car runs rough from cold to hot. Not only at either cold or hot. I also did a compression test and found all cylinders are at 190-195 psi so compression is good on all cylinders.

530 i
06-10-2010, 02:18 AM
As the misfire appears to be from one bank it may be worth checking the short earthing strap has a good connection and the nuts are tight, the one that runs from one of the spark plug coil securing studs to the stud in the head.

raceyBMW
06-10-2010, 02:19 PM
All other plugs connected correctly (ICV, TB, ASC, etc..)? Double check everything, because I had the same issue after ripping apart the intake to do the valley pan. I swore I labeled all the plugs correctly, but sure enough I had switched a couple around and it ran rough.