OK, so I thought I was imagining things but lately this has gotten serious.
I am experiencing a severe (and I'm not prone to hyperbole) flat spot in my 550i when accelerating, somewhere in the 2000-3000 rev range, regardless of the gear I'm in. There is just no response from the engine as I increase accelerator pressure in this range, then response kicks in over 3000 rpm. These ranges are approximate as they seem to vary a bit and I can't always catch a view of the tach when this happens. If I'm in 1st and hit the magic flat spot then it's almost as if the car has stalled.
I don't live at altitude, use hi-test gas and the car has only about 3000 miles on it.
It ain't the clutch because the engine isn't revving.
I searched the E60 forum for "hesitation" and didn't come up with anything quite like this. Before I bring the car in (I'm going to have them address the wheel-turn-at-low-speed-moan as well) I'd appreciate any feedback or experiences of a similar nature (OK, I know my search came up empty but maybe "flat-spot" would have worked).
To answer the specific question posed, I can only say BP Hi-Test, sometimes Mobil Hi-Test. Don't know the Ethanol content.
It's really a problem with the A/C on (like today). That's why I didn't notice it when I picked the car up in December (I keep the A/C compressor OFF unless I really need it).
I realize this is not a turbo and the torque doesn't come on at low RPMs but 3000RPM in 3rd gear shouldn't be too much of a problem; besides, more often than not it's really a miss (rather than the old rubber band feeling because there's no torque).
Yes, I think it's time to bite the bullet and take the ol' (well, actually, new) 550i back to the dealer. Their first step should really be straightforward; i.e. computer analysis. If they give me the "we can't reproduce it" line, then I'll think what to do next.
I've had similar problems and the dealer found no issues. They basically made me feel like an idiot. I've found when I drive in sport mode, the problem goes away so that's what I do.
Same dead spot for me. But just like ajaiello, it goes away in sport mode. I also took it to the dealer and they said everything was fine.
This doesn't make any sense why there is dead spot when sport mode is turned off. In sport mode, it doesn't go up to 6th gear and screws up the already bad fuel efficiency. I want immediate response + 6th gear with my 550
To the OP...do you have a 6 speed manny??? If so then there has to be something going on.....not sure what but my 550 pulls like a freight train from 1200 on up to redline.
If you have an automatic then this is reason #457 why I've never owned an automatic. I'll decide when to shift, not a piece of software. Unfortunately I think this is a software isse. Probably isn't anything "wrong" in terms of a defect. But if the "sport" mode makes it go way, then that's about all it can be....a transmission software issue that BMW will deem "normal vehicle operation".
There is something definitely wrong, whether the dealer can find it or not. I am kind of busy now so I want to wait a few weeks before bringing it in for service (this way I can focus all my energy on what I know will be a difficult task ). I can be in 2nd, 3rd or 4th and accelerate between 2K and 3K and I'll get a stumble. Especially with the A/C compressor on but regardless, it's there, and since we're talking what should be an engine "sweet spot" I really think it needs to be addressed.
Thanks to you and all the posters for your encouragement. Frankly, my dealer's service department has always been pretty good (except when they couldn't fix a leaking oil cap in my old M5) but I'm steeling myself for an ordeal. I'll let you all know how it comes out.
Well, just to update those of you who might be interested.
I brought my car in to Rallye, they kept it overnight because the tech said he experienced what I experienced and they needed to do more tests, then I got a call this morning telling me that my car is "operating as designed". This means, of course, that they have no idea what's wrong or how to fix it.
Instead of leaving my car with Rallye I'm going to pick the car up and try to bring it to a competent dealership.
I have a similar problem. Just an FYI - I heard from the tech that there is a new software update expected next week to hit dealers. Not sure what it is, but its supposedly helps with this + 2-1 downshift issue. Anyone have more info of the update? BTW - mines a 2010 550i
Thanks. There seems to be a definite issue with SAT-equipped 550s.
Honestly, I don't know if this is related to my issue or not. Frankly, as someone mentioned above, it's hard to see why changing transmission modes would have an effect.
When it's colder and there is no A/C compressor working the problem is not very noticeable, although still present. When it's hot/humid with the compressor working then the problems trying to accelerate through 2-3K can vary from simple hesitation on the less annoying end to flat spots and mild jerking on the more severe.
Normally I would say, well, they put my car through a battery of tests, opened what they called a "PUMA" case with BMW, etc., and "found nothing wrong". But of course I know "found nothing wrong" actually means "we see the problem but can't/don't want to bother fixing it". Since others with 6MTs don't seem to have this I will need to figure out what my next step is, whether speaking with the Service Manager at Rallye or taking it to, as I say, a hopefully competent dealer.
nlk10010...i have brought my 5 series to rallye before and they are just terrible at service they rank #2 as far as i see it .
with life quailty bmw in brooklyn placing #1
take it to Manhatten on 57th st,
they have an excellent service center
or if you wanna drive a lil while take it up to connecticut
I was trying to give Rallye the benefit of the doubt because I like the sales guy and the service rep I dealt with years ago for my M5 was also very nice. However, I should have realized when they couldn't stop oil leaking from under the fill cap on that M5 that Rallye service was incompetent. This recent visit just confirmed that.
Too bad, because I contacted the service "manager" explaining the situation but was ignored.
If I just prevent others from making the same mistake I did (i.e. servicing a car at Rallye) I will at least have accomplished something.
I am gathering opinions on competent BMW service centers and will certainly take your recommendation for Manhattan under advisement (even though the sales guy I dealt with there was unsavory). By Connecticut do you mean BMW of Greenwich?
I'm also going to keep an eye on BMW of Bayside. They just opened a new service center near my house and, while they used to have a terrible rep on the Internet, the time I dealt with their salesman I was impressed and things seemed to have gotten better lately.
But did they say they could diagnose it? "Never heard of it" is of course the answer to a question I assume you didn't ask.
BTW, 6-speed or auto?
As to RPM, it occurs 2500 rpm, sometimes a bit over 3000 and various other spots in 2-3K. Most often (or most noticeable) in third gear.
Given that others have not experienced the problem it's an issue that must take a competent service department to diagnose and correct. I am lucky that I know Rallye isn't one but I am gathering recommendations for good service departments and when I find one (I'm sure I will) I'll let everyone know.
Hi there. I know what you are talking about in terms of dead spot nlk10010. I have an 08 6MT and also notice in rpm range of 2500 - 3000 when I try to accelerate aggressively (i.e. floor it) the car doesn't not respond, it just slowly begins to accelerate. This is also in the third gear. I've taken the car in before to get looked at and mentioned it to the SA, but they of course said they couldn't reproduce the dead spot. I'm planning to push harder with my BMW service center to look into it when I'm back from vacation. i'll be happy to share any info I get beyond the "never heard of it." Please let me know anything you discover as well.
Hi there. I know what you are talking about in terms of dead spot nlk10010. I have an 08 6MT and also notice in rpm range of 2500 - 3000 when I try to accelerate aggressively (i.e. floor it) the car doesn't not respond, it just slowly begins to accelerate.
-snip-
It simply "does not respond" or, put another way, doesn't go anywhere.
At one point I thought it might have something to do with the DTC, because I also get some non-responsiveness in 1st gear, sometimes, when applying the accelerator. I'd say the clutch or wheels were slipping except for the fact that the engine RPMs don't change. But it's hard to tell. We can certainly all agree to keep each other informed about our search for competent service departments.
Now I need to check my 1st gear -- I never accelerate hard out of 1st mostly because I'm stuck in traffic, but I'll let you know if I have the same issue. I'm going to be gone for two months and plan to tackle this issue with my service center when I'm back. Hopefully you find answers before then! Good luck with it.
This torque/horsepower curve posted by Billd104 cannot be correct. By definition, torque equals horsepower (lines cross) at 5252 RPM. In this graph, they appear to cross at 3400 RPM.
If you don't believe me, check the following site:
Relationship with torque
For a given torque and speed, the power may be calculated. The standard equation relating torque in foot-pounds, rotational speed in RPM and horsepower is:
Where P is power, ***932; is torque, and ***969; is rotations per minute. The constant 5252 comes from (33,000 ft·lbf/min)/(2***960; rad./rev.).
The copy/paste function did not display the formula shown in wikipedia correctly, so you'll have to go to the site to see it for yourself.
Also, I drove my 550 more aggressively than normal on the way to work this morning to test for peak torque. Peak torque is developed well above 4000 rpms, not 3500 as shown in the graph.
The graph is just plain wrong. Not only does it not describe a 550 engine, but it describes no engine ever made.
I just purchased a 2007 550i with SMG and notice a lag or no response around 3500-4000 RPMs. Putting in Sport Mode doesn't help either. Seems like the car just doesn't want to go! I'm going to take it to the dealer to have it checked out and hopefully they won't say its operating as designed.
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