3.0si - idle speed fluctuating
- Thread starter z4wannabe
- Start date
What sort of time frame passes between low and high revs? Doesn't sound like much to be concerned about, but it's not normal either.
How would you describe the most notable differences between the driving experience of each engine and why are you not yet sold? I've not experienced the M54, so I am just curious. Sorry to go OT, but you started it.
How would you describe the most notable differences between the driving experience of each engine and why are you not yet sold? I've not experienced the M54, so I am just curious. Sorry to go OT, but you started it.
Thanks BCW. I'll give it some closer attention next time I'm in it and see what I can report.
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(Yes, I did go OT - thought twice about it, but here goes:
The N52 has a deeper sound - someone said it sounds like a BMW 3 litre diesel on start up, which is not far off, although the revs confirm it's not of course. It's a touch more 'droney' at motorway speeds, but that might be Coupe versus Roadster. Either way, it's louder, smoother, but perhaps a little less 'mechanical' / raw. I think I preferred the sound of the 3.0 M54.
Performance-wise, it's got a bit more kick, but I'm not yet sure it's necessarily more fun.)
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(Yes, I did go OT - thought twice about it, but here goes:
The N52 has a deeper sound - someone said it sounds like a BMW 3 litre diesel on start up, which is not far off, although the revs confirm it's not of course. It's a touch more 'droney' at motorway speeds, but that might be Coupe versus Roadster. Either way, it's louder, smoother, but perhaps a little less 'mechanical' / raw. I think I preferred the sound of the 3.0 M54.
Performance-wise, it's got a bit more kick, but I'm not yet sure it's necessarily more fun.)
Nova2k7 said:least yours doesnt do this!
this happens each time i press the break and on start up it jumps up and down like a yo-yo! from almost stalling to 1500rpm!
Looks a bit like the fault I have at present on my 3.0si which BMW are desperately trying to locate and fix, see thread http://www.z4-forum.com/forum/viewtopic.php?f=3&t=46501
Either way that is not normal Nova! Have you tried to find out what is causing it at all?
Swiftly said:Nova2k7 said:least yours doesnt do this!
this happens each time i press the break and on start up it jumps up and down like a yo-yo! from almost stalling to 1500rpm!
Looks a bit like the fault I have at present on my 3.0si which BMW are desperately trying to locate and fix, see thread http://www.z4-forum.com/forum/viewtopic.php?f=3&t=46501
Either way that is not normal Nova! Have you tried to find out what is causing it at all?
well from what ive looked into (and ive had this for almost a year now) it would appear to be the brake servo! as it only happens when the breaks are pressed. once the car warms though the symptoms are less!
Nova2k7 said:Swiftly said:Nova2k7 said:least yours doesnt do this!
this happens each time i press the break and on start up it jumps up and down like a yo-yo! from almost stalling to 1500rpm!
Looks a bit like the fault I have at present on my 3.0si which BMW are desperately trying to locate and fix, see thread http://www.z4-forum.com/forum/viewtopic.php?f=3&t=46501
Either way that is not normal Nova! Have you tried to find out what is causing it at all?
well from what ive looked into (and ive had this for almost a year now) it would appear to be the brake servo! as it only happens when the breaks are pressed. once the car warms though the symptoms are less!
Mine did this for a while before my throttle body gave up.... turns out it was a gear with a snapped tooth inside, the motor turns, misses the tooth, then winds on a bit more to compensate. I did this for a week or so before the gear gave way and it just revved and fell 500-2000-500-2000.
It's probably not that if it just does it on warm up and brakes, but might be useful to others if they have similar issues.
wattsie
Thanks wattsie, that's good information for anyone with an M54. The throttle body on the N52 and other valvetronic engines is normally a passive device for backup if the valvetronic should fail, so is unlikely an issue with such engines. M54s have been known to develop throttle body issues, so definitely worth a look if you have one.wattsie said:
Ok not sure how relevant this is but I've noticed that when I have my foot on the break and press the gas peddle nothing happens apart from the revs rising slowly until it gets to about 1200rpm and the stops! After taking my foot off the peddles the car almost stalls! After doing this earlier I ended up with this!!
