StormBreaker

Hello.
I have e60 525xi 2006 and it started missfiring on random cylinders exactly at 6k rpm. DTC are always on different cylinders. 2-3-4, 3-5-6 etc.
Spark plugs and coils are brand new.

donpb

Which device or software are you using to read the codes?

StormBreaker

Ista+ on pc and bimmer tool on phone.

seanjordan20

What brand plugs and coils did you use and have you done a smoke test. I'm thinking you have a leak somewhere if you used OEM coils and plugs

StormBreaker

Coils are Bosch, spark plugs also Bosch, but I don't remember the exact model. All were replaced before15k km. The missfire started 1 week ago or 2k km.

twh

I'd check a few things...

• re-seat all spark plug coils
• re-seat all spark plug coil connectors
• check the small-ish bare braided ground strap that goes to the valve cover...it connects in 2 places as I recall
• check the large ground strap that is under the engine on the right side...it lands on the inside of fender just aft of the right wheel well and on the right side drive shaft housing -- if this one has never been replaced, just do it proactively anyway...it will go at some point and it may not be obviously broken

donpb

Yeah, I have fixed misfires by simply re-seating plugs and connections.

donpb

+1

StormBreaker

I didn't have time to play with the car till yesterday. Last night while cruising normal speed ~2k rpm the car started to missfire really bad and on diagnostic it says missfire on 3,4 and 6 cylinder. I remembered that the missfire started to happen after changing crankshaft position sensor. The symptoms were: the engine cut off while driving and bunch of warning lights like 4x4,DSC,Transmission fault came on. I scan the car with ista+ and it showed crankshaft PS. I replaced it with brand new Delphi sensor, cause that's the only one they had stock and I needed the car running. No codes about it since then.
So is it possible the new sensor to be bad out of the box and not working properly, but does not store any fault codes? 2 days ago I had problem with cold start. The engine crank like 3 seconds till fire up and stalled immediately 2 times. No error codes

seanjordan20

Not normal for rhe sensor to be bad oit the box at least that one. I remember I had a bad CPS and was forced to get a Delphi sensor because I couldn't wait for an OEM to show up. I think Delphis is fine but ultimately the OEM is the sensor you should be using. Multiple misfires wouldn't be a sensor issue though but long crank can be. Did you have oil on the connector when you replaced it? If so was the leak fixed first before changing the sensor. You need to do a smoke test and check fuel pressures. Other than that you're wasting your time.