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Discussion Starter · #1 ·
I've got a slight concern for my 03 M5 that I have now owned for about four months:
When the engine is cold up to the point when all the lights go out on the tachometer I experience an uneven pull, which is especially noticable in the non-sports mode with moderate acceleration. It feels like a slight jerking with no or slight acceleation.
I've had it in for service twice (for other reasons) and at both times did I point out my concern to the service-representative. At the first occasion the person that serviced the car confirmed my statement and checked for alarms but found none, but updated the DME with the latest firmware without any noticable difference.
I now have it in again and the service-guy said that this is normal for the M5 while it is cold.
As an aside I did a half-hearted test of the 0-60 performance (with the engine warm!) to make sure there's not any issue with engine performance and my rough estimate from my watch was about 7-8 seconds, i.e. nowhere near the sub-five seconds to expect. I shifted at about 6500 rpm's which may or may not be optimal.

Anyone have any comments? Is the cold engine issue normal and is 7 secs what you'd get if you're not a race-driver with precise shifting?
 

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some cold stumbling is normal. On my car, as my mafs (mass airflow sensors) started acting up, it got worse. Perhaps your mafs are starting to go (how many miles do you have).

FWIW, powerchip software does a lot to get rid of the cold stumble.

As for 0-60, i've never tried it, but i'd think even a half hearted attempt should give you 6ish seconds, not 7-8.
Mike
 

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Hi

I'm no expert, (& there are lots on this site), however this sounds familiar to problems I had recently, & guess what, MAFS & camshaft sensor!!!!

There's loads written on this site about these two problems, check out how to check MAFS, this may help.

Or, I could be totally wrong, I'm sure somebody will let me know!!!!!

Gareth
 

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I have had my 2000 M5 for about a month and a half now.
When cold, or before the tacho clears 4000 to 4500 rpm in orange, acceleration is jerky until you force it through the 2000 to 2500 rpm range. During the cold weather, I have adopted the approach of getting the car out of the garage, a couple of revs whilst parking up, then leave it running a minute or two until idle speed drops from just above 1000 rpm to about the 650 mark - drive of then and all is good.
Before reading this board I tried for a rapid launch from standstill and soon discovered that you could easily start cooking the clutch - the smell and the lack of bite gave that away (and realising that the rpm was up at 4000 before fully engaging worried me at the time) - I then went for a more sensible launch, and with no experience of this car I pulled a 5.5 second launch - totally happy that this car could do a sub 5 second with skill and concentration. I do not intend doing launches like this but it was a bench mark test for me (as for you too it would seem).
For me, the kick is overtaking with start of manouvre revs above 3000 that does it for me - so satisfying. I have driven the car hard now and my clutch is good - I accept that anyone can fry it if you put the power on before full engagement.

Hope any of this helps - BUT, 7 to 8 seconds suggests to me some lack of power.
 

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Hi Gareth,

I see the bezels around the lamps in your front bumper are not black.
Are they painted or chromed?
If so, how did you do it and how do they come out?

Thanks for any info.

Rob
 

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Discussion Starter · #6 ·
Thanks for the great info!

I read the threads on the MAF-testing.... I've got about 37K on the car so according to my reading they shouldn't pose a problem, but I know what I'll be doing after picking up the car from service tonight anyway!
Perhaps will I learn some information that I can pass on to service when I turn my car back in to get my ordered parts installed next week.

I have my own theories regarding car-dealers willingness to deal with warranty-work, which I have all reason to believe would cover a replacement in my case.
 

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Had my Y2k with 27k miles in to the Stevens Creek BMW recently with the same issue. They kept the car for 3 days so they could do cold starts in the morning. The service tech felt the jerkyness but said he couldn't get a fault code. He hooked up a fuel flow meter but couldn't get any conclusive results.

Now I just get up a little earlier, let the thing warm up in teh driveway for a minute until the idle rpm drops and all is well.

I think this is a problem with the ECU programming at startup that BMW is just not interested in persueing. The techs are hesitant to say anything is wrong with the car if it doesn't show as a "fault code".

Dennis



beam5ter said:
I've got a slight concern for my 03 M5 that I have now owned for about four months:
When the engine is cold up to the point when all the lights go out on the tachometer I experience an uneven pull, which is especially noticable in the non-sports mode with moderate acceleration. It feels like a slight jerking with no or slight acceleation.
I've had it in for service twice (for other reasons) and at both times did I point out my concern to the service-representative. At the first occasion the person that serviced the car confirmed my statement and checked for alarms but found none, but updated the DME with the latest firmware without any noticable difference.
I now have it in again and the service-guy said that this is normal for the M5 while it is cold.
As an aside I did a half-hearted test of the 0-60 performance (with the engine warm!) to make sure there's not any issue with engine performance and my rough estimate from my watch was about 7-8 seconds, i.e. nowhere near the sub-five seconds to expect. I shifted at about 6500 rpm's which may or may not be optimal.

Anyone have any comments? Is the cold engine issue normal and is 7 secs what you'd get if you're not a race-driver with precise shifting?
 

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beam5ter said:
I read the threads on the MAF-testing.... I've got about 37K on the car so according to my reading they shouldn't pose a problem, but I know what I'll be doing after picking up the car from service tonight anyway!
That is a good idea! For completeness, please post the results in the MAF-testing thread too preferrably including air temperature/barometric pressure/altitude/humidity.

David
 

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mottati said:
some cold stumbling is normal ...
Same here. Immediately on start-up, my rpms pulse slightly for about 10 seconds, and then the idle becomes steady. Throttle remains a little balky for the first minute or so of driving. Has been like that for my past year of ownership. I make an effort to really baby it until it warms up.
 

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Speaking of cold startup..



How long do you guys usually start driving the car after startup in the morning. ?


I usually wait about 45 sec - 1 min + before I start drving mine.
I always wait till that whine is gone before moving it..

And I am never push the car before all the amber light gone from the tachometer.... so I have not really experience any of this (granted I just bought my car about 2.5 weeks ago) :)


Regardz,

J Irwan
 

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J Irwan said:
Speaking of cold startup..



How long do you guys usually start driving the car after startup in the morning. ?


I usually wait about 45 sec - 1 min + before I start drving mine.
I always wait till that whine is gone before moving it..

And I am never push the car before all the amber light gone from the tachometer.... so I have not really experience any of this (granted I just bought my car about 2.5 weeks ago) :)


Regardz,

J Irwan
In the warm climate of south Florida, I wait just long enough to buckle my seat belt and engage sport!! Most folks agree the best way to warm up a car is to drive it gently to everything is up to operating temps. In the cold of winter, some warm up time like you suggest is wise, to get the fluids thin enough to start doing their job (oil, gearbox, diff).
Even with the PC software I get a very slight resistance between 200-2400 rpms for about the first minute. After that, all is silky smooth. I think better software will take care of most of the problem. I am very happy with PC software and they still have 14 or 30 day money back guarantee, so it is something to consider!
Regards,
Jerry
 

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i have a 00 no mods a fresh service. i too have the slugish starts until the car has been on for apx 2-3mins, then runs like a dream. i've done 0-60 in 4.9 and feel i could do better with more practice however the clutch is always on my mind. :M5launch:
beam5ter said:
I've got a slight concern for my 03 M5 that I have now owned for about four months:
When the engine is cold up to the point when all the lights go out on the tachometer I experience an uneven pull, which is especially noticable in the non-sports mode with moderate acceleration. It feels like a slight jerking with no or slight acceleation.
I've had it in for service twice (for other reasons) and at both times did I point out my concern to the service-representative. At the first occasion the person that serviced the car confirmed my statement and checked for alarms but found none, but updated the DME with the latest firmware without any noticable difference.
I now have it in again and the service-guy said that this is normal for the M5 while it is cold.
As an aside I did a half-hearted test of the 0-60 performance (with the engine warm!) to make sure there's not any issue with engine performance and my rough estimate from my watch was about 7-8 seconds, i.e. nowhere near the sub-five seconds to expect. I shifted at about 6500 rpm's which may or may not be optimal.

Anyone have any comments? Is the cold engine issue normal and is 7 secs what you'd get if you're not a race-driver with precise shifting?
 

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I had the same symptoms until I replaced the MAFS, and now it's running like a dream. I wouldn't even say there is any hesitation when cold, and I'm with Jerry on this one... I just start it up and drive off. By the time I make it to the first stop sign, the idle has already dropped below 1000 RPMs.
 

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Cold engines have been discussed many times in the past, but this thread seems like a good time to bring it up again. The M5 engine is a highly tuned motor with very tight tolerances. As a good practice, you should never drive it hard until it fully warms up. This means getting the oil warm, not just the water. I don't rev my engine beyond 3000 RPM until the oil temp is almost up to the first mark. If you are experiencing stumbling while cold, it may be because you are pushing it too hard too soon.
 

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robord535 said:
Hi Gareth,

I see the bezels around the lamps in your front bumper are not black.
Are they painted or chromed?
If so, how did you do it and how do they come out?

Thanks for any info.

Rob
Rob
I didn't know they were non-standard. I've only had the car a couple of months, must have been the previous owner.

Gareth
:cheers:
 

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I had a pulsating idle when cold with another car- turned out to be intake air control valve. Just a mild surge/pulse under light acceleration... no fault codes... just guessing.
 

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Simple solution...

Powerchip your beast.

Solve all of my problems of cold engine issues.
 

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This is interesting. I always warm up the Motor for about 45 seconds prior to drving. and I always make sure Oil T° and Water T° are at normal (hot) prior to pushing the car hard. Just makes sense to me. And I have never had a stumbling issue. Again I do not push it at all when not up to regular oerating temperature.

Once when I was in a rush, I did not perform the "45 second" warmup, and I had a few minor stumbling issues. But it did go away.
 

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Discussion Starter · #20 ·
Thanks for all the useful info and references. Since I'm still fairly new on the board, it's sometimes hard to find what you're looking for at first.
Anyway, the info about the MAF-testing was great and I had the l/h fuel consumption turned on while driving home from work yesterday. Without trying anything too excessive on the freeway, I did at least test WOT in second through fourth gear, spending little time in the high-end RPM's and only in second gear, but I did see up to 135l/h.
Interestingly enough, the service-statement from earlier this week said nothing was done to remedy my concern, but it feels like the car IS running better. Did they actually fix something without telling me?? To cover up something??

I will attempt some more scientific testing, hopefully over the weekend and report my results to the MAF-thread. The only problem is that one of those not too uncommon 100+ periods is under way in Sacramento, i.e. daytime temperature lingers around the 105F/40C mark and yesterday it had only dropped down to about 86F/30C at 9:30pm :sad2: - good thing the A/C works well....

- Jan.
 
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