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Discussion Starter #1 (Edited)
While at sears point this past weekend, under a couple of pretty hard runs, about 20min into a session on the track, i get a pretty heavy miss and an SES light. Oil temp about 240, coolant temp right in the middle (i know that means little), engine very weak, but will rev beyond 4k (so not limp home, right?). I pull into the hot pit, shut off for 20sec or so, re-start and all if fine, no SES, car runs great, back on track...
(i should add, i took a few runs with some students/passengers in c and d run groups, not pushing the car as hard, and no problem with misses/ses)

Happens again, do the same, happens again, do the same. On the drive home, car feels a bit sluggish (maybe i'm just feeling slow after being at the track though) and i think the exhaust tone might sound different (could be mental as i've already been thinking cam sensor). Get home, let car cool, take a drive, all seems fine.

Pull out the Peak, table 18, codes 01, 63 (or b3), C4 and C6.
Code01, i think a red herring. I had the car dynoed a couple months ago, the shop pulled the wrong fuse (they initially pulled 17 and 31, 31 is for fuel pump). Code 01 is fuel pump relay. Maybe meaningless?

Code 63 is some self test thing, so that doesn't sound related (and my car seems to have this code often, without an ses light. If it's b3, that cat efficiency, bank 5-8, still doesn't sound like that'd cause a miss. (and i have new cats).

Codes C4 &6 are misfire, cyl 1 and cyl 3. OK, so i know which cylinders were missing, but why? Wouldn't a CPS throw a cps code?
Any thought's appreciated, i'm CPO, so i'll call the dealer tomorrow, but i'm curious.
 

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I just changed intake/exhaust CPS on bank 2 (showed up using Peake) and some gaskets because of oil where the sparks are. I thought everything should be fine, but I still get the exact same problem that you have. It seems ok most of the time, but if I drive it hard, I get the strange exhaust noise and almost no power, restart will fix it. I get misfire on cylinder 1 and 5. I now think it's the MAFs, have tried to clean them twice and seems to help, but will probably buy new ones. Similar problems earlier described in this forum seems to point towards the MAFs.

Rgds,
Kjell

mottati said:
While at sears point this past weekend, under a couple of pretty hard runs, about 20min into a session on the track, i get a pretty heavy miss and an SES light. Oil temp about 240, coolant temp right in the middle (i know that means little), engine very weak, but will rev beyond 4k (so not limp home, right?). I pull into the hot pit, shut off for 20sec or so, re-start and all if fine, no SES, car runs great, back on track...
(i should add, i took a few runs with some students/passengers in c and d run groups, not pushing the car as hard, and no problem with misses/ses)

Happens again, do the same, happens again, do the same. On the drive home, car feels a bit sluggish (maybe i'm just feeling slow after being at the track though) and i think the exhaust tone might sound different (could be mental as i've already been thinking cam sensor). Get home, let car cool, take a drive, all seems fine.

Pull out the Peak, table 18, codes 01, 63 (or b3), C4 and C6.
Code01, i think a red herring. I had the car dynoed a couple months ago, the shop pulled the wrong fuse (they initially pulled 17 and 31, 31 is for fuel pump). Code 01 is fuel pump relay. Maybe meaningless?

Code 63 is some self test thing, so that doesn't sound related (and my car seems to have this code often, without an ses light. If it's b3, that cat efficiency, bank 5-8, still doesn't sound like that'd cause a miss. (and i have new cats).

Codes C4 &6 are misfire, cyl 1 and cyl 3. OK, so i know which cylinders were missing, but why? Wouldn't a CPS throw a cps code?
Any thought's appreciated, i'm CPO, so i'll call the dealer tomorrow, but i'm curious.
 

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mottati said:
Happens again, do the same, happens again, do the same. On the drive home, car feels a bit sluggish (maybe i'm just feeling slow after being at the track though) and i think the exhaust tone might sound different (could be mental as i've already been thinking cam sensor). Get home, let car cool, take a drive, all seems fine.


Codes C4 &6 are misfire, cyl 1 and cyl 3. OK, so i know which cylinders were missing, but why? Wouldn't a CPS throw a cps code?
Any thought's appreciated, i'm CPO, so i'll call the dealer tomorrow, but i'm curious.
I had both CPS intakes go at different times. The first one, intermittant SES light. Just before repair, I got solid SES and a throaty sound out of the exhaust. I thought it was my imagination, but not. Second time, SES light, but no noticable sound difference. Both times, I did NOT go into limp mode, but I was only street driving so that may have made some difference.
Regards,
Jerry
 

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Discussion Starter #4
I've got recent mafs, maybe a year and a half old or so (20k miles), and that was different symptoms for me.

I'm not going into limp home, car will rev beyond 4k, but there is a pretty heavy miss at all rpms. The heat seems to be a factor, if i'm cruising along with the D or C group, no issues, but when i'm really geting on it, it happens.

I've had a vanos unit go bad before, but that did throw the car into limp home, wouldn't reve above 4k etc.

As an aside, the M5 continues to amaze me (and everyone who rides in it!)! My first run on Sat (which was the last a session run of the day) i went out on track with a group of instructors (2 e46 M3s, an e30 race car) and a couple of fast students in 911 GT3's and the M5 was hanging with them for 3-4 laps, until the miss started... I actually got a passing signal from the instructor in the e30 track car (that would have made a great picture)
MIke
 

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Mottati,

Did you talk to Bill? I wonder what his take is on the miss? Hope all works out . . . It is probably no big deal . . .

P.S. Let us know if you have any warranty issues given the mods.

Take care,

Shawn


mottati said:
I've got recent mafs, maybe a year and a half old or so (20k miles), and that was different symptoms for me.

I'm not going into limp home, car will rev beyond 4k, but there is a pretty heavy miss at all rpms. The heat seems to be a factor, if i'm cruising along with the D or C group, no issues, but when i'm really geting on it, it happens.

I've had a vanos unit go bad before, but that did throw the car into limp home, wouldn't reve above 4k etc.

As an aside, the M5 continues to amaze me (and everyone who rides in it!)! My first run on Sat (which was the last a session run of the day) i went out on track with a group of instructors (2 e46 M3s, an e30 race car) and a couple of fast students in 911 GT3's and the M5 was hanging with them for 3-4 laps, until the miss started... I actually got a passing signal from the instructor in the e30 track car (that would have made a great picture)
MIke
 

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Discussion Starter #6
No not at this point. I found another post where it was just a bad plug. I did replace my plugs not long ago, maybe 6k miles, but maybe i have a dud, or a weak coil.
As for the warranty, i have a good relationship with my dealer and SA, so i don't expect any major problems, don't think this is in any way related to the headers.
Mike

2003 M5!!! said:
Mottati,

Did you talk to Bill? I wonder what his take is on the miss? Hope all works out . . . It is probably no big deal . . .

P.S. Let us know if you have any warranty issues given the mods.

Take care,

Shawn
 

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Sounds like you were having fun at the track!

mottati said:
No not at this point. I found another post where it was just a bad plug. I did replace my plugs not long ago, maybe 6k miles, but maybe i have a dud, or a weak coil.
As for the warranty, i have a good relationship with my dealer and SA, so i don't expect any major problems, don't think this is in any way related to the headers.
Mike
 

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Discussion Starter #8
OK, well i got a call from my SA. They found 3 fault codes, fuel pump relay (occured once), cat efficiency (occured once) and a misfire on cyl 8 (occured twice) similar but not exactly what my peak tool told me. They also said my adaptations were at the far end of the range, so they would reset them and see what happens. He said not enough to go on to replace any parts yet.... although i did get another valve cover gasket and a radiator cap from my cpo warranty...
I was going to replace my fuel filter, seems like a good idea at 62k but it's special order and i want my car back, so that can wait a couple of weeks!
Mike
 

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mottati said:
OK, well i got a call from my SA. They found 3 fault codes, fuel pump relay (occured once), cat efficiency (occured once) and a misfire on cyl 8 (occured twice) similar but not exactly what my peak tool told me. weeks!
Mike
I had SES and diagnosis was bad drivers cat (I assume cat efficiency). Car seems to run fine. It is being ordered and replaced under warranty. No hassles.
Regards,
Jerry
 

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mottati said:
As an aside, the M5 continues to amaze me (and everyone who rides in it!)! My first run on Sat (which was the last a session run of the day) i went out on track with a group of instructors (2 e46 M3s, an e30 race car) and a couple of fast students in 911 GT3's and the M5 was hanging with them for 3-4 laps, until the miss started... I actually got a passing signal from the instructor in the e30 track car (that would have made a great picture)
MIke
Mike
As good as the M5 is, it still needs a good pilot. Give yourself some credit! kinggf
Regards,
Jery
 

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Discussion Starter #11
I had new cats put in under warranty just before getting my headers done! Lucky timing for a cat efficiency code to come up! But they're new. Did certainly have a miss, which the cats wouldn't cause. I'm guessing if the dme senses a misfire, it shuts down that cylinder to protect the cats, cylinder walls etc from too much fuel being dumped down. A restart seemed to get it going again. At any rate, i'll go beat on it for a while to see if i can get it to re-occur.
Mike

gsfent said:
I had SES and diagnosis was bad drivers cat (I assume cat efficiency). Car seems to run fine. It is being ordered and replaced under warranty. No hassles.
Regards,
Jerry
 

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mottati said:
While at sears point this past weekend, under a couple of pretty hard runs, about 20min into a session on the track, i get a pretty heavy miss and an SES light. Oil temp about 240, coolant temp right in the middle (i know that means little), engine very weak, but will rev beyond 4k (so not limp home, right?). I pull into the hot pit, shut off for 20sec or so, re-start and all if fine, no SES, car runs great, back on track...
(i should add, i took a few runs with some students/passengers in c and d run groups, not pushing the car as hard, and no problem with misses/ses)

Happens again, do the same, happens again, do the same. On the drive home, car feels a bit sluggish (maybe i'm just feeling slow after being at the track though) and i think the exhaust tone might sound different (could be mental as i've already been thinking cam sensor). Get home, let car cool, take a drive, all seems fine.

Mike I had a similar problem with my 00. I was taking off from a light a little harder then normal and as soon as I went into second the SES light came on and I noticed right away that the exhaust tone changed. I scanned the DME for codes and came up with a exhaust cam sensor failure. I ordered the part but by the time I was ready to install it the SES light had come on and off twice (intermittent I guess). Each time the exhaust tone changed. I installed the cam sensor and reset the DME and hadn't had a problem since.

Hope this helps

Joe
 

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Discussion Starter #13
hudson said:
Mike I had a similar problem with my 00. I was taking off from a light a little harder then normal and as soon as I went into second the SES light came on and I noticed right away that the exhaust tone changed. I scanned the DME for codes and came up with a exhaust cam sensor failure. I ordered the part but by the time I was ready to install it the SES light had come on and off twice (intermittent I guess). Each time the exhaust tone changed. I installed the cam sensor and reset the DME and hadn't had a problem since.

Hope this helps

Joe
Thanks, but no code for cps, just codes for misfire. We'll see if anything comes back.
Mike
 

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Discussion Starter #15
hudson said:
I would look for a bad coil or plug in that cylinder.

Joe
That was my thought too. I just put new plugs in 6-7k miles ago, dealer won't do anything until it recurrs (which may not be until the next track day!) so this may be an excuse to go with aftermarket coils...
Mike
 

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I vote for a bad MAF.

All 3 symptoms on the car I just bought, fuel pump, cats and multiple misfires. Exactly the same. They replaced almost everything in the fuel system, cats and the problem did not go away. Changed the MAFS, and wham. Perfect car again.
 

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Discussion Starter #17
Bugeater said:
I vote for a bad MAF.

All 3 symptoms on the car I just bought, fuel pump, cats and multiple misfires. Exactly the same. They replaced almost everything in the fuel system, cats and the problem did not go away. Changed the MAFS, and wham. Perfect car again.
MAFS are less than a year old, and when they were replaced, i was getting a MAFS code (along with several related codes)... I did check the fault codes, as did the dealer. Only thing that came up was misfire on 2 cylinders (that i feel is relavant).
mike
 

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I had a series of SES lights and pulled the codes on my Peake. Initially they were misfire codes as well as secondary ventilation codes (don't know what that signifies...). Had my inspection II and had the plugs replaced. Still intermittent SES lights. Finally I had your symptoms; changed exhaust note, decreased power and new SES. Took it to the dealer who pulled exhaust CPS codes. Will be having it replaced under the CPO tommorrow. Hope it works. I've cleaned my MAFs twice and have had only one MAF related code. Car has 60K on it...I guess it could still be the MAFs, eh? Will let you know.

Gordon
 

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Discussion Starter #19
i spoke with another bmwcca instructor who had the same issue as i with his m5, under really hard use. Never re-occured for him either. I'm going to put a new set of plugs and coils in, just for the heck of it. No CPS code, so i'm not chasing after that just yet.
Mike
 

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What is an exhaust CPS code? What part is being replaced?

My last code was exhaust efficiency . . . whatever that means hmmm I think I have had 3 on and off SESs in the last 2 years. I had a real problem before that -- once I had my x-pipe installed.
 
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