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Discussion Starter · #1 ·
I've been reading posts from several forums concerning the E46 M3 engine failures for some time now, and I have yet to find answers to my questions. IS THIS engine failure issue a potential problem in ALL M3's? Or is it a rare poduction/material defect that are found in a limited percent of cars produced? Finally, has BMW found a way (whether material or design) to prevent these problems from occuring in newer production cars? PLEASE, if anyone knows answers to any of these questions, please reply!
 

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Automotive Monomaniac
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I've heard of engine failures in E36 M3's - usually due to driver error (shifting into the wrong gear at speed does it).

I haven't heard any confirmed flaw with the E46 M3 engine, so I doubt there is a serious mechanical problem.

Even if there is an issue, the car is under warranty and a new engine is just a few 'dealer days' away...
 

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Parking Spot Maven
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I have read here and on other boards that this 'condition' is caused by over-revving (which the dealer can verify by hooking the car up to their computer), not by engineering faults. The revs come up extremely fast, and if you aren't good at shifting or if you miss a shift, well... just like any other car, bad things happen.

As an aside... I have found the age (and thus experience) of some M3 drivers these days to be rather surprising... I picked my friend's son up a few weeks ago at a high school and milled around the lot a bit while I was waiting. I came across TWO E46 M3's in the lot. The kid I picked up knew who owned them... they were both students. I have noticed the same thing when I see M3's around here... the owners are often times very young.

I'm certainly not suggesting that ALL drivers between the ages of 16-18 are cluebies and that they are the only ones that have blown engines in these cars, but I am saying that this might be a contributing factor to the 'condition' that exists with E46 M3's.

--SONET
 

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Sonet, there is clearly a malfunction. SMGII M3s are over-over-revving and blowing. The is supposed to be impossible.
 

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I like cookies.
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Nick325xiT 5spd said:
Sonet, there is clearly a malfunction. SMGII M3s are over-over-revving and blowing. The is supposed to be impossible.
SMG does NOT upshift automatically. You hit the fuel cutoff if you don't shift, since the engine cannot take a sustained 8000 rpms :dunno:
 

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Doesn't explain how some SMGII M3s are getting close to 9K...
 

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According to the stories listed by people with SMGII engine failures there have been. I also saw pictures one guy took of his tach indicating 8500ish.
 

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A sudden sense of liberty
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There appear to be at least two distinct failures that people are experiencing. One is a failure of the main bearing; this appears to be an engineering (either design or assembly) flaw unrelated to over-revving the engine. The other is valvetrain damage related to over-revving the engine, similar to that seen in E36 M3s. This seems to be related to driver error.

However, as Nick points out, a number of cars with SMGs have experienced over-revs, and have also experienced engine failure. Also as Nick points out, it *should* be impossible to over-rev an SMG car. The engine computer has a fuel cutoff that theoretically prevents going much past the redline, and unlike manual tranny cars, the shift computer is not supposed to allow you to engage a gear that is too low for the speed you are traveling.

So, while driver error may explain some or all of the manual transmission over-revs, it does not explain the bearing problems or the apparent flaw in the SMG program. What is unclear is how common either of these latter two flaws are.
 

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The SMG has protection against over rev on downshift not up shift. The upshift protction should be the same as all our E46s which we have seen doesn't always work.

Ultimately it is the application of the loud pedal that leads to an over rev. No one should rely on the car to keep from over revving.

My .02
Haus
 

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Rest in peace, Coach
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Nick325xiT 5spd said:
Doesn't explain how some SMGII M3s are getting close to 9K...
This number just keeps going up and up. So far the HIGHEST registered RPM is 8450 from and ECU dump sustained for 5+ min that I've read on bimmer.org E46 M3 forum...And I lurk there regularly.

This is like one of those sociology studies, everytime someone tells a tale and gets passed on, there's more embellishment on the truth. And from what I've gathered on the E46 M3 board, so far out of thousands of owners that post regularly on that board, there's only been 5-6 CONFIRMED cases of engine blowing due to Over-rev, and from what I can see ALL of them resulted from driver's error.

Hell, Jim in Oregon trackes his SMG-II M3 regularly and IT hasn't blown up yet...And I'm sure he drives it just as hard as anyone in their right mind would.

And for ***'s sake, one of those blown engine belong to that ALEX (not our Alex) idiot that used to troll the E46 M3 forum. Now how much stock can you possibly put in that?
 
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