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Flat out the best post I have ever read on any topic! You did an incredible job with this Mert. The forum definitely owes you a debt of gratitude. My hat is off to you, sir!
:applause:

Bill
 

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Flat out the best post I have ever read on any topic! You did an incrediblejob with this Mert. The forum definitely owes you a debt of gratitude. My hat is off to you, sir!
:applause:

Bill
+1

I know that you don't want to say much about another persons car, but can you tell us what year it is?:dunno:

Chuck
 

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Just an FYI for those who may have the SES on because of a p0411 code, YOU CAN STILL PASS SMOG IN CA. All you need to do is warm up the car, clear the codes, drive about 10 miles, check the DME that all systems are complete and you'll pass. The key is that all systems have completed.

Obviously staring at an SES light is annoying at the least, so I would still suggest doing the powerchip or bmw fix, but if you have smog coming up at least you know now. :D
 

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So what does all this mean to a guy like me:
I live in S. Florida where a cold start is 55F
We don't have emissions testing any longer
I just bought my M5 10 mos ago it has just over 20k miles.
Its driven daily now and I enjoy the full sweep of RPM

If I wanted to avoid this early-what should I do. Powerchip workaround? Do nothing?
 

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Do nothing?
Exactly that. As a percentage of M5s out there, the ones affected by this issue is very small. Forget about it and enjoy the car. :)
 

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great work mert.

questions:
1. any idea if the car ever had the "implausible coolant temp" error code (i.e., thermostat stuck open)?

2. do you have a rough idea of the owner's driving style?
 

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I still wonder if the fact that most of our cars burn 1+ quart of oil per 1000 miles doesn't have more to do with this than the fuel. This motor looks just like the insides of the passages of a rotary Mazda motor (which by the way injects oil directly into the combustion chamber)

Just a hunch.....

RR

PS do you know the oil consumption on this motor?? and thanks so much for the info!!!
 

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WOW :eek:oohhh:....looks like someone just SH!T on the engine. Does seafoaming the engine help at all getting out some/most of the carbon? Have you guys tried it?
 

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Well, perhaps I have not been paying attention, but this picture was a surprise to me!
A
Me too! did not know the ports were actually behind the valve. The e34 has them in the exhaust manifold, which seems much more logical.
 

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here's a few pics for comparison from my engine. This was at 72k miles, almost 3 years ago. I was tracking the car pretty regularly, at least 4 weekends per year, combustion chambers were pretty clean (compared to merts pics) and the sec. air port was maybe 20% blocked.
 

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Me too! did not know the ports were actually behind the valve. The e34 has them in the exhaust manifold, which seems much more logical.
I didn't realize the rich, fuel laden exhaust gas was ported directly into this cool air passage!

Seriously, I'd consider closing those little holes and keeping contaminants from getting itno the secondary passage.

And there is NO WAY i'd pay to have the system cleaned out... unless it was a $100 cpo co-pay!

A
 

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I didn't realize the rich, fuel laden exhaust gas was ported directly into this cool air passage!

Seriously, I'd consider closing those little holes and keeping contaminants from getting itno the secondary passage.

And there is NO WAY i'd pay to have the system cleaned out... unless it was a $100 cpo co-pay!

A

+1
 

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what a horrible, horrible design. I am curious though, why does this problem not appear often on the e39 540i which shares a very similar secondary air system?
Mark, the 540 DOES succumb to the same problem. As I said elsewhere, it is my belief that the problem is not as prevelent on the 540, but it does happen to the 4.4 as it happened to mine. If it is related to oil usage then I am a little surprised my 540 has the problem since it uses no oil whatsoever. Neither does my M5 (knocking on wood now). The 540s do get the same problem- obviously Mert's expert opinion would be great at this point on the "Why did this happen, to this car, to this extent?" If it is oil comsumption-related, then the fact that more M5s use oil might explain it? Mert, jump in at any point now that we know what the problem entails, give us the "How" and to what engines?

Bill
 

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Yikes! Those pics are of such a nature that a few owner will lose sleep over them. Thank you very much for taking the time and effort to posting those.

I am curious to know how similar heads look for European M5's? If we can see some pics of a head taken apart on a few German cars, it could certainly confirm or deny the rumor that carbon build up can be prevented by extended driving at high RPMs and high speeds. It certainly have been seen before that autobahn driving takes care of carbon deposits in other engines.
 

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Just thinking outside the box here...but what do you guys think of installing some sort of water injection system? Seems like it would keep the combustion chambers, pistons and possibly the intake and exhaust ports much cleaner. I would think that on a car that doesn't have clogged aux air ports, it might actually help keep them clear. Thoughts?
 
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