BMW 540i 1998 V8 - Heavy misfire, 3 fault codes present 139, 75, 64Archived Message
Posted by Joe McGeoghan on April 20, 2006, 8:16 am
This car arrived with heavy misfire. Retrieved 3. codes: 139 Activation, MAP cooling 75 Misfire, total, with cylinder cutout 64 Misfire, cylinder 2, with cutout.
#2 coil and plug renewed.
Scoped primary trace to coil - ok. Injector trace ok - same as 1, 3 &4.
Road test under heavy acceleration, engine develops misfire - #2 injector not switching. Clear codes, injector receives signal - so ECU turning off this cylinder. Wiring harness appears ok.
Engine generally seems 'fluffy', perhaps not as crisp as other 540s I've driven.
I was next going to check catalytic converters.
Would partially blocked cat cause ECU to detect this misfire and shut-down #2 cylinder? Seems unlikely to me...
Any obvious pointers, experience would be welcome.