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Hi,

The 19th of June I was driving back from work to my house this is a drive of roughly 180km's BUT the most fun part for me is that the drive goes for more then 100km over the A31 in Germany which is a so called autobahn:haha2::haha2: so most of the time I'm pretty fast home. This time sadly not.......

The journey started like normally drive into Germany put cruise control on 260km/h and drive north. It didn't take too long until I noticed a Porsche 911 Turbo who was driving around 250km/h but didn't want me to let pass by. Offcourse I knew I would loose this (my car is still limited on 270km/h) I decided to check if I can put up while accelerating away. It was not too bussy on he road but from time to time we had to stop since other cars were also using this road and overtaking other users on the road........

So in short we had several accelerating sprints on which my M5 really could follow the 911 Turbo pretty well, offcourse he was faster but the gap was way smaller then I expected only when I hit the limiter he really pulled away, but starting from 140/160/200 the m5 really could keep up and I heard a glorious note from the Porsche his exhaust who was screaming all over the place......

BUT THEN

After several pulls and thumbs up from both of us we hit roadwork, before that you have to drive 120km/h so me coming from 270 and he I expected driving even faster we had to break down to 120 which is pretty heavy breaking after that 80km comes and then you hit the road works....

Still no problem but when I entered the road works suddenly my engine started shaking violently, enginelamp went on but I couldn't stop since I would block the whole road then (only 1 lane was open) so in my effort to safe the car I was thinking less revs and put it in 6th gear. This only made it even worse so I shifted back until 3rd gear in which the engine didn't shake too much anymore, luckily after around 3km's the roadwork stopped and I could pull over on the side of the highway....

After putting on the warningsignals / putting down a warning sign / wear the bright yellow jacket (all of this you have to do in Germany) I opend the hood and looked under the car if any fluids were leaking. This was not the case, then I called the ADAC to come over or pick me up so me and my car would be towed away. After an hour of waiting still nobody arrived and I checked my oil which was still around 3/4 so I knew there was still oil in the engine making me a little less afraid. At this time the oil temperature was down to minimum temperature.

After another hour waiting the ADAC arrived and brought me and my car to their base in Emden where they read out the car looking for failures. The found a code, which I wrote down for my BMW dealer and erased it. it was saying that cylinder #8 stopped working which made me offcourse very afraid (engine failure). Then they erased this code and read out the car again to see if the failure popped up again. Strangely enough it didn't come back, after which we decided to start the car. To make things even more strange it worked perfectly no shaking anymore or strange sounds also cylinder 8 was working as if nothing happened anymore, we let it run for around 10 minutes changed revs still car worked perfectly....

Since I was also in contact with my BMW dealer the whole time, informing them, making decision to start the car again etcetc... They still wanted to be extra carefull (and myself also) and asked ADAC to bring the car and myself to Groningen they were open until 9pm so we could park the car straight away in their workshop.

In short we did and the day afterwards I flew to Pakistan for my work. Overhere I had no internet at first but right now I have so I checked my email and got a mail from the dealership. They couldn't find anything wrong on the motor everything works very well BUT my differential was dying and it need to be changed completely. I just reacted in another thread about this diagnose regarding the differential.....

But what could have caused my engine failure:
-hitting the limiter several times
-driving a little bit faster then normal and then braking very hard
-oil temperature stays always a little bit above normal, while speeding I put the heating on 32 degrees so the heat from the engine can go away.....

In short I hope you guys have some clues what could happened there, it doesn't give e to be honest a safe feeling anymore regarding my engine and that is something I have to trust offcourse.

Looking forward to your idea's

Regards,
Eric
 

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What you're describing sounds like an engine misfire. Cylinder #8 is one of two that's closest to firewall, so all the spirited driving probably elevated engine/transmission temperature close enough to cause an electrical glitch. Since cooling and restarting the car did not reproduce the issue, it leads me to believe it was electrical, not mechanical (e.g. worn spark plug or stuck injector). I would recommend keeping an eye on the ignition coil on cylinder #8 and get a PEAKE reader so you can pull codes on your own.

"Cruise control at 260km" - wow how unfair the world is, we'd get thrown in jail for that kind of antics here! hiha
 

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Eric,

Invest in a Peake code reader to have in the glovebox, it is a great tool to inform you on what is happening with your M5. Knowing if you have a serious problem or not is a lifesaver for these electronic vehicles.

For extended travels it really is a must.
 

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I have had a similar experience on occasions of prolonged high speed with hard acceleration into the limiter. My car would hit fuel cut or something, go into limp mode, and did once misfire like you describe. In limp mode it just seemed to reduce power, until it came down to a reasonable speed and I could still drive with reduced acceleration power. Once I stopped and restarted my car was back to normal, I never got to the bottom of the issue as I don't get the opportunity to do those speeds often. I first experienced it 4 years ago, a few times in between and most recently about 3 months ago again under the same circumstances, I have no idea, but there must be some condition that the DME is protecting the car from maybe.
Could plug overheating cause this? To the experts.
 

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I agree with Bimmerule. Sounds like possibly the #8 coil got too hot and starting having trouble. DME noticed an issue with the cylinder unrest and shut it down. Once car cooled, code cleared, and restarted it was fine.

Please update the thread if you get the symptoms again, especially if you then find a diagnosis and repair.
 

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I experienced the same type of scary engine noise one night last fall. It was during a spirited drive with a couple of board members. I hit the throttle on a left turn drifting onto the highway, hammered the throttle to try and create some distance between me and the other 2 beasts when suddenly the power really dropped despite having the throttle down and I was like WTF? The engine sounded horrible like debris was bouncing around inside it so I immediately thought something major just broke. I quickly pulled over and shut her off. I started it up again about 30 seconds to a minute later and it sounded perfectly fine! Another WTF moment. I continued on and caught up with the guys for more spirited driving. It hasn't happened since that night so I have chalked it up as an electrical SNAFU. I work with computers and software everyday and these things just happen sometimes.

Eventually months later I got some codes prompting me to replace the bank 2 PITA intake CPS but there's no way to correlate if the CPS caused that one-off event.
 

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Had a similar issue on my drive home today, on the highway, engine started running rough. Got home, no ses light, but there was a cyl #7 misfire code CA and misfire with empty tank code 95. Ordered a new coil, hopefully that is all I need. Had close to a half tank of fuel, hoping it's not an injector or fuel pump issue.
 

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It seems to be far more common for coils to fail on these cars than injectors. In fact, I don't remember a cylinder misfire definitely being caused by a bad injector.

The coils live in a tough environment, enclosed (remove the covers for longer coil life!), no cooling, heat conducting up from the combustion chambers, and high compression ratio/efficient cylinder filling requiring high voltages to generate the spark. And then add on to that some hard driving which will really raise the temperature in the oven.

So my money is on a bad coil.
 
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