e39 m5 carbon build up

[hqstu 780]

Hello,

Has anyone any experiences / information on the potential issue of carbon build up in e39 M5 engines?  In both the secondary air system and in general?  I've been reading it can be a problem on US Spec LHD cars, but unsure as to Euro spec RHD's (ours).  Also related to fuel quality and how often the big jandel is utilized... more nana driving accelerates carbon build up?

Has this caused any problems here and solution?

[hybrid 1043]

I think the only carbon buildup really you need to worried about is on your spark plugs.... maaaaybe valve seats but would have to run fairly rich for that to happen.

[M3AN 4016]

@BreakMyWindow will probably know if it's an issue or not.

[M3AN 4016]

It would be fantastic if all your posts were that complete, accurate and helpful Ron. 

Could I do it on the cheap without the weight by just using shorter springs on the LHS? 

 

[BreakMyWindow 1874]

All e39 m5's get the secondary air circuit in the heads blocked up with carbon. This triggers a fault code called : 'Minimum flow of secondary air' Google search it and you will see what happens and how to fix it. This does not affect performance so I wouldn't worry.

Edit, some light reading : http://www.m5board.com/vbulletin/e39-m5-e52-z8-discussion/128129-secondary-air-system-carbon-build-up-removal-pictures.html

The exhaust valves can get carbon build up which will affect performance but that is rare and i think is created by short drives and lots of idling.

Edited December 11, 2016 by BreakMyWindow

[hqstu 780]

Wow, fascinating... there's a whole different world out there...

[BreakMyWindow 1874]

Yep, no one should own or drive one as they will block up the inheritantly flawed secondary air emissions system..

[M3AN 4016]

17 hours ago, BreakMyWindow said:

Edit, some light reading : http://www.m5board.com/vbulletin/e39-m5-e52-z8-discussion/128129-secondary-air-system-carbon-build-up-removal-pictures.html

Whilst I understand that's an extreme example it's a fascinating read, thanks.

[BreakMyWindow 1874]

4 hours ago, 3pedals said:

Air injection systems were introduced in the mid 60's as a means to reduce emissions, with modern engines these tend only to be used during the cold start phase.

Like any system on a modern engine they need maintenance, specifically ensuring they are working and periodic replacement of the non return valves and is a good starting point.

If your car has such a system and you are not sure of its' condition - get it checked and if you plan to keep the car do some Preventative Maintenance on it.

Rash claims of the epic failure   of these systems can be found relating to  Audi, BMW, Porsche Volkswagen etc.  or basically any manufacturer who employs such a system. The reality is the system is only as good as the operator and in this case that is the car owner.

Audi, BMW, Porsche and Volkswagen have no control over the .01% of retards that buy their cars and don't maintain them, then whine all over the internet  about fatally or inherently  flawed designs.  

How many whines are there about PCV systems yet people continue to use sh*t oil, skip services and then complain about engines sludging up ??

There are plenty of inherently flawed designs in the automotive industry Ronald. No one really gives a sh*t about one which only affects cold-start emissions. If this issue did affect the engine in terms of engine performance then it would be a different story.

 

[M3AN 4016]

Yeah, I read quite a few pages in and I'm not personally interested in what causes it, rather than it can happen at all. Since many of these will not be with the original owner it seems it would be difficult for prospective or new owners to know if they have the 'problem' or not.

Unless the owner's manual actually tells you how to mitigate this then it's my opinion that you can't blame the owners/drivers because if they're only doing what they're told to do...? If they're using the highest grade of fuel available to them and driving it like a nana are they really doing anything the dealer/manual said they can't? Or not doing something they were told they should? My M3 manual certainly doesn't say take it to redline frequently but many advocate doing so. e36 M3's (and e39 M5's?) were sold new in NZ before the recommended 98 RON was available meaning 95 was the best available.

I'm not arguing with you Ron, just sharing my thoughts, and I have no opinion on the merits of other opinions expressed herein but I respect Martin's knowledge of e39 M5's.

 

[Allanw 1071]

I recall Dads E30 manual saying something along the lines of: if you've done a lot of town/low speed driving, to take it on the highway and use a gear or two lower for a while .

It sounded like a PC/Professional way of telling you to give it a gentle italian tuneup.

[M3AN 4016]

I'm sure your approach is better than mine Ron, thanks for letting me know.

/threadparticipation.