BenAnd

Hi

Have some of you V8 4.0L ( and V8 3.5L ) owner's ever experienced that when the car ( engine )is cold , that it seems that one or two Cylinders not are runnig properly ? , when the car have been driven for a short time , turned off , and then started again , then it runs as it should , it's only in the first cold phase that there are problems with uneven engine time.
I have valvetronicen suspect that soot by those who are causing the problem, is there anyone who has any experience with this problem, any help will be received with gratitude

sdg1871

I had a similar problem recently with my 4.8L V8. I started the car, the check engine light came on and the engine was running very roughly. So I turned the engine off and restarted it. Sure enough, the problem went away and did not return. I chalked it up to a bug in the ECU.

safetywork

I have experienced rough idle when the ambient temperature drops (as in winter below 50 degrees F) combined with the car not having been started for a couple of days. No check engine light ever came on and the rough idle went away by the time I'm at the stop sign just down the street.

IzzE60

I was told by BMW North America this is not normal. My 550i goes in on Tue to the dealer so a BMW engineer can take a look. I found a SIB about a software upgrade that fixes it. I will let you know what BMW does.

BenAnd

Hi guy's


Thank you for your message, we have so far tried the following.

When the error occurs and the engine running rough, so light engine lamp in the speedometer, as I said, if we after a little ride, stop the engine and start again, then the error is disapered and the engine running smoothly thereafter.

Decommissioned cylinder head and cleaned the cylinder head, valves and piston tops of soot.

We have also tried with an updated engine software , that diden't solve the problem either

We will try and look for the SIB you mentioned , please let us know what you come up with after your visit to the BMW dealership "izzE60".

If any one else have an idear , please "tune" in

Thanks in advance

05545i

Rough Idle cold can be caused by uneven filling of the cylinders due to the valvetronic intermediate levers. There is TIS bulletin about this issue. The problem is fixed by replacing these levers.

IzzE60

Does the valvetronic intermediate lever problem apply to the 550i engines? I thought that was only for the engines up to 2005?

Da_Meister_22

i hope BMW does a better job with their V8 engines this generation around :sigh: