E60 M5 Idling flat spot

[Air Support]

So having got the car back from the garage yesterday with the Vanos issue fixed (apparently) I find that I still have a flat spot when increasing revs in neutral at around 1100-1500rpm.

I say flat spot, but the engine runs roughly to the point where you can feel the engine vibrations through the car seat.

I'm back down to the dealer tomorrow to talk to the technician that did the Vanos fix.

I'm sure the car didn't do this when I got it just over a year ago, but now I'm wondering if this is a case of TADTS.

Do any of you find the same issue at just above idle?

Thanks

[ecain63]

Have you taken it for any spirited runs since you got it back? Might need a bit of an Italian tune up. I used to drive mine like miss daisey but during a rolling road session you could see flatspots on the graph where the car was going stale due to my lack of abuse. A few power runs later and the graph was as smooth as silk. Might just be in need of some heavy right foot action.

[Air Support]

Eddie

Yes saw your rolling road graphs and the engine map changing as it worked harder, however I don't think this is the case.

We're talking much lower revs.
How does your engine rev at around 1100 - 1500 - surely not rough?

[skeeterm5]

My sounds like a lot like a diesel, not sure it feels as though it has a flat spot though.

S

[andygtt]

Mine sounds like a diesel on idle but is smooth from 1000rpm onwards even in higher gears

[ecain63]

Mine is very smooth throughout the range so the rough sensation your getting is obviously abnormal. If the Itai tune up isn't an option you need to he thinking mapping or maybe an intake/air issue, maybe even plugs.

For you other guys, to rid your M of that diesel clatter you need to change your exhaust. Mine just sounds like a V10, from 1krpm right through to 8.5krpm.

[zip929]

ecain63 said:

Mine is very smooth throughout the range so the rough sensation your getting is obviously abnormal. If the Itai tune up isn't an option you need to he thinking mapping or maybe an intake/air issue, maybe even plugs.

For you other guys, to rid your M of that diesel clatter you need to change your exhaust. Mine just sounds like a V10, from 1krpm right through to 8.5krpm.

Might I concur with Eddie. The v10 sound is a treat and quite possibly addictive!

[Air Support]

andygtt said:

Mine sounds like a diesel on idle but is smooth from 1000rpm onwards even in higher gears

O/T
Ah - didn't realise you were an M5 owner as well as the Noble Andy.
Good choice of cars!

[zip929]

zip929 said:

Might I concur with Eddie. The v10 sound is a treat and quite possibly addictive!

Still trying to work out what I do not like about this car and I cannot find anything.
It impresses me more everytime I drive it. It is is just an amzing car and I am privileged to be able to run a car like this.
It is car nirvannah, for the dogs as well!

[ds666]

I've noticed the same vibs if "blipping" the throttle in neutral - had it investigated by BMW but no faults found . Be interested to know how you get on as it does seem odd .

[Air Support]

So it seems its a question of TADTS

Spoke to the technician today and demonstrated the issue. Once he'd seen it (took a while to happen as needed to get up to full operating temperature), he called in a more experienced colleague. The experienced chap then told me that it's just something this engine does and recommended that it is not reved at all when not under load (i.e. in neutral).

I have to say that since having the Vanos issue fixed the engine does feel more responsive and this rough spot isn't an issue when in gear. Just not quite what I exepcted from a V10 engine I guess.

Interestingly, I have also noticed that the rough/vibration feeling is worse in 500hp mode than 400hp which I think is encouraging from the viewpoint of probably not a balance or mis-firing issue, just an attribute of the way the engine runs on no load.

I look forward to being able to compare this with other owners at a meet at some point!

[Somesayhis]

I have also noticed a similar trait with my 2006 E60. Although to me it feels more like a resonation problem rather than a rough/misfire. It clears up after about 1100 rpm. Very faint but certainly noticeable. I had the car in BMW recent for service and mentioned it to the service manager at my local M approved dealership. No faults found.

I wonder if the exhaust is at fault, or an unbalanced pulley?

[Air Support]

It is at least a little encouraging that others seem to have this trait but with no fault found by the dealer

Car is fine when in gear so I guess I'll just leave it alone and enjoy