[David Cheresh]

I recently purchased an Alpine White M5. I love the car and have 1000 miles on it. However, I have been experiencing a troubling hesitation during acceleration at low RPM. It feels a little like a turbo lag. Has anyone had a similar problem and what was done to correct it? I was hoping to have some feedback before I speak to the BMW dealer prior to my 1200 mile checkup.
Thanks
DAVE C.

 

[greg]

At the risk of asking what may seem like a stupid question - are you sure the DSC isn't kicking in? If it does, the yellow light (that comes on when you switch DSC off) will come on momentarily. This will absolutely cut the throttle way back. You get around this by switching the DSC off.

Other questions - do you have sport mode on? This quickens throttle response.

The engine is very tight when new, but it shouldn't have any lag as long as you're keeping the revs above, say, 1200 RPM before the clutch is fully engaged. The engine develops a boatload of torque from low RPMs - do NOT slip the clutch at higher RPM - by about 2000 it MUST be fully engaged or you'll burn up the clutch in a hurry.

 

[David Cheresh]

Originally posted by greg:
At the risk of asking what may seem like a stupid question - are you sure the DSC isn't kicking in? If it does, the yellow light (that comes on when you switch DSC off) will come on momentarily. This will absolutely cut the throttle way back. You get around this by switching the DSC off.

Other questions - do you have sport mode on? This quickens throttle response.

The engine is very tight when new, but it shouldn't have any lag as long as you're keeping the revs above, say, 1200 RPM before the clutch is fully engaged. The engine develops a boatload of torque from low RPMs - do NOT slip the clutch at higher RPM - by about 2000 it MUST be fully engaged or you'll burn up the clutch in a hurry.

Greg,
This acceleration lag happens independently of the DSC and seems to occur whether in sport or regular mode. I do notice that it is considerable worse when cold. However, even when warm the car lags or bogs at low RPM and seems to lurch at about 2000-2500 RPM. Any further insight is appreciated.
DAVE

 

[greg]

OK - sounds like a genuine problem. I'd suggest taking it to service.

 

[bobafett]

What's your build date? Could be that you're one of the clutch-slipping cars (more on this via email if you want).

--Dan

[email protected]

 

[David Cheresh]

Originally posted by bobafett:
What's your build date? Could be that you're one of the clutch-slipping cars (more on this via email if you want).

--Dan

[email protected]

Dear Dan,
It was built in late July of this year. I was unaware that any of the cars had a clutch problem. Did this problem show up as a low rpm lag? Thanks for you help.

Dave

 

[bobafett]

Well, I've recently undergone some major clutch issues. Originally, I believe that BMW was issuing weak clutches. This was "resolved" in my case, but the new cluitch died within 4 days. So then after two weeks I got a "modified Z8" clutch and all is well.

Symptoms that I experienced ranged from slipping between gearshifts no matter how delicately executed (notoriously between 3-4). But later on, it slipped if i gave the car a little gas. It didnt matter which gear, but obviously higher gears were worse.

Clearly, acceleration lag is present because the clutch wasn't "catching," so there was no movement in correlation to the engine speed. I would have your dealer check it out. If your clutch is slipping, then at least you know what the problem is. If not, then I'd be interested to hear what they say.

Best of luck,
--Dan

 

[TD]

Dave C.

With almost 4K mi I have noticed some hesitation at low RPM. Maybe I am too forgiving, but at this point I assume it is still a break-in thing.

For example, taking a turn while in 3rd and then pressing on it. The engine seems to take a moment to gather and then whoooosh. Not a clutch issue.

I have not watched the RPMs that close but under 2k or so, I expect some "relative' hesitation. I also usually have the DSC on, if it is off you can bet the RPMs are up so I dont know if it is a factor, but I doubt it.

Dont know if any one cought the Motorweek (TV show I've seen on PBS and cable) coverage of the M5. But I have it on tape and they complained about the "hunt and peck of the dirve-train at low RPMs" That seems harsh and no other review of the M5, that I recall, complained about low RPM performance.

But Motorweek also said that the CD player "skiped over every other bump". I live in the snow belt and have yet to hear a skip on mine.

I can't say if you have a problem or not. But I can that I have had somewhat similar experiences with my 93 325i and 96 M3. Both cars continued to get better past 10K mi.

But I must say, since the M5 makes more touque under 2K RPM than the 540 does at peak, I did not anticipate any hesitation.

On this issue, I would love to hear from someone with many more miles on their M5.

TD

 

[MarcK]

My car has 4K miles, and also sometimes shows some slight hesitation to take full throttle at low RPM (around 2k). This doesn't happen when I open the throttle slowly. Doesn't seem to be related to engine temperature. I was a bit worried about it, but the M5 I drove at the driving experience in Spartanburg had the exact same behavior. So I'm assuming it is normal. Would be nice, if it disappeared with more miles

Marc

 

[stevem]

my car was built in 5/00 and i have felt the problems you describe. I have 5500 miles on it. In the mornings it is a litte "touchy" but that goes away in 2-3 minutes. Hesitation on acceleration sounds like a problem.

stevem

 

[stevem]

Originally posted by stevem:
my car was built in 5/00 and i have not felt the problems you describe. I have 5500 miles on it. In the mornings it is a litte "touchy" but that goes away in 2-3 minutes. Hesitation on acceleration sounds like a problem.

stevem

Please note that I have NOT felt the problem you describe. Sorry for the typo.

stevem

 

[alpywhite]

I dare say that fly-by-wire may never duplicate the intimate feel of a mechanically activated throttle.

Alps

 

[bobafett]

I'm just over 6k and don't have that problem either. I'd have it checked out, just to be on the safe side. And if they give you some run-around BS about that being normal, kindly ask them to check it out anyways.

--Dan

 

[kbb2me]

I too have the same lag problem and the issue with cold engine surges. I askeed the dealer to check it out at the 1200 service but they said they needed to schedule a longer appointment to diagnose the problem. I now have 3500 miles on a 6/00 build and am ready to have the following addressed; vanos noise (sounds worse than a diesel VW Rabbit
brake noise
acceleration delay
cold engine surges
rip out the cup holders !
vibration noises from low bass on stereo
For $80 k (with taxes), I can't be picky enough.