Does anyone have any insight to this??
BMW n45b16a 2006 116i (non eccentric shaft, non balancer shaft)
Came in many moons ago due to correlation between crank and cam signals being out of sync. Had a genuine timing chain and guides as well as oil suction tubes etc renewed and it ran much better and cured the logged faults. However after some months the customer reported a repetitive misfire like symptom after driving 15-20 miles on the motorway and coming off for her junction, is when it'd run rough.
Timing has been checked and besides "misfire detected several cylinders" nothing else showed apparent. Faults were cleared and live data checked and nothing seemed incorrect. Software update was performed and customer read on google and requested for 4 new pencil coils to be installed. And also at the same time new ngk plugs fitted
Recently customer has now come back in saying similar behaviour but now it's misfiring throughout any journey travelled. Got the car in, and it runs BAD. Barely holding idle. Hesitation when You try to push past the rough patch. Which by approx 2500rpm it clears past the misfire.
Timing chain alignment checked again.
Checked to see if a newer update to software is available.
Checked vanos pressure solenoid for ruptured green seal and or mesh filter contaminated by old timing guide plastic. Clean as a whistle.
Inlet manifold has been smoke tested. No vacuum leaks.
Compression test carried out via compression tester and pico scope. No loss of compression whatsoever.
Feels as if it's got an insane amount of unmetered air characteristic. Does anyone have any ideas or past experience?
