Petrol Diagnostics

Post a Response

BMW 645 Ci 2004 - Poor idle #

Posted by Nigel Bennett on June 19, 2009, 5:36 pm

Year of Manufacture *: 2004
Engine Code or Type *: N62 B44A

Hi all,customer reports "misfire" at idle at normal temperature .
Though by no means does this "misfire " the idle is not as smooth as one might expect from this engine type. No DTC present gases in good balance,all HT in good condition. The only item that doesn't appear to be right is the crank case ventilation system!
We have had an older version of this engine in last year with a more sever random multiple misfires present,on this occasion the breather system had excessive vacuum,the oil filler cap was very difficult to remove.We re newed the system and fixed the vehicle , now this new vehicle is showing the same excessive vacuum at the filler cap and dip stick,however the system
design is total different so is this normal for this later engine? Regards Nigel.

Re: BMW 645 ci poor idle!

Posted by Pete Mutlow <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT1569' width='330' height='300' border=0 style='border:none;'> on June 19, 2009, 10:30 pm, in reply to "BMW 645 ci poor idle!"
Peter Mutlow

Hi Nigel,

02 reading? Had something similar with a smaller engined BMW last year. Had high 02 reading which turned out to be a leaking pcv valve. Would have thought a "misfire" would present itself with higher than normal 02 and "unbalanced" gases.

Regards

Pete M

Re: BMW 645 ci poor idle!

Posted by Glen Strachan <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT1463' width='330' height='300' border=0 style='border:none;'> on June 22, 2009, 8:22 am, in reply to "BMW 645 ci poor idle!"
Glen Strachan

Have you checked compressions ? Is this not the V8 engine that was getting changed at low mileage under warranty due to worn bores ??

Re: BMW 645 ci poor idle!

Posted by Nigel Bennett <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT5463' width='330' height='300' border=0 style='border:none;'> on June 22, 2009, 8:58 am, in reply to "BMW 645 ci poor idle!"
Nigel Bennett

Gases all good,this doesn't appear to have a vacuum leak,the excessive vacuum in the engine,that's what I think is the answer !
Thanks Nigel.

Re: BMW 645 ci poor idle!

Posted by steve walker <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT1169' width='330' height='300' border=0 style='border:none;'> on June 23, 2009, 7:04 pm, in reply to "Re: BMW 645 ci poor idle!"
Steve Walker

Hi Nigel

I have only just seen your post , these engines do suffer with the crank case breather valves failing causing the symtoms you describe. They are situated on both rocker covers ( 1 each bank ) and are a cliped on plastic disc clipped onto plastic moulded rocker cover under the main coil covers.
These are not expensive and really easy to replace.
Hope you get it sorted , if you need any more info let me know.
Kind regards
Steve

Re: BMW 645 ci poor idle!

Posted by Sean Murphy <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT1788' width='330' height='300' border=0 style='border:none;'> on July 28, 2009, 3:19 pm, in reply to "Re: BMW 645 ci poor idle!"

Please excuse my ignorance - what is a "pcv" valve?

Re: BMW 645 ci poor idle!

Posted by Pete Mutlow <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT1569' width='330' height='300' border=0 style='border:none;'> on July 28, 2009, 7:55 pm, in reply to "Re: BMW 645 ci poor idle!"
Peter Mutlow

Hi Sean,

I believe PCV valve stands for Positive Crankcase Ventilation valve.

Regards

Pete M

Re: BMW 645 ci poor idle!

Posted by Nigel Bennett <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT5463' width='330' height='300' border=0 style='border:none;'> on July 28, 2009, 9:27 pm, in reply to "Re: BMW 645 ci poor idle!"
Nigel Bennett

Sorry Guys,customer didn't return for further investegation! Thanks Nigel.

Re: BMW 645 ci poor idle!

Posted by Kevin Apps <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT2589' width='330' height='300' border=0 style='border:none;'> on July 28, 2009, 9:45 pm, in reply to "Re: BMW 645 ci poor idle!"
Kevin Apps

Hi Nigel
Well at least Sean has learn something !!!
Kev.

Re: BMW 645 ci poor idle!

Posted by Ed Kaps <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT5536' width='330' height='300' border=0 style='border:none;'> on August 8, 2009, 12:16 pm, in reply to "Re: BMW 645 ci poor idle!"
Edward Kaps

And Steves post would have fixed it, so two good points raised.
Ed Kaps

« Back to index

[ Petrol Diagnostics ]