[Dormermike]

Hi all

I've noticed that if I rev my N53 engine in neutral (it's an auto) it is smooth as you'd expect up to 2500 ish rpm where the whole car shakes (can feel it if the door is open) and that then goes by 2800 rpm and it smooths out again. Latest revision injectors, no codes, no idle misfire, no sooty exhaust. Running great apart from this very narrow slice of shakey RPM.

Any ideas please? I've had lots of straight six engines and never noticed this before. I've had this car two years and couldn't tell you if this is new or not. You'd not notice it in day to day driving unless you were looking for it.

Thanks
Mike

[Dormermike]

This was mistaken for a wheel balance issue by a BMW dealer. Thats how it feels. They had it for a whole day.

Logically looking at the engine it's going to be plugs coil packs or injectors...

Rough running on rheingold shows nothing amiss. The engine does feel like it's firing on 5 cylinders during this RPM. I was testing it on the motorway earlier. It is mostly only on light throttle.

Anyone know how to track down which cylinder is faulty? I could go pulling coil pack plugs but prefer not to do that as it requires holding the revs at 2800 RPM or so.

No codes.

[frenchi]

Got that on two N53 - HPFP ...no codes no errors full power and once Hpfp and low pressure sensor replaced, no more vibration resonance.

[Dormermike]

Ugh.. need to get rid of this car

Thanks. The vibration is at 2000 rpm, not higher as I stated. Why does the HPFP cause that?

[Dormermike]

Originally Posted by frenchi

Got that on two N53 - HPFP ...no codes no errors full power and once Hpfp and low pressure sensor replaced, no more vibration resonance.

How was it diagnosed? I doubt the talented engineers at my local BMW dealer will be able to do anything without the computer codes to guide them...

[frenchi]

You can start with coils as these are cheap and easy to replace,but once plugs coils and injectors replaced we got only hpfp left and that solved the problem ...not a single code and car idle was perfect.

[Dormermike]

If have the fully comp BMW warranty so I should be covered. My concern is the complete lack of skills at the BMW dealer which means I have to keep going back and forth as they try out new things.

[bfleming]

Originally Posted by Dormermike

Anyone want to buy a f10 530i..

I'm passively looking at F10's at the moment, but my budget will make you cry more than your current running woes do!

[Dormermike]

Originally Posted by frenchi

Got that on two N53 - HPFP ...no codes no errors full power and once Hpfp and low pressure sensor replaced, no more vibration resonance.

Can you elaborate on the symptoms that you saw please? Did it happen only when hot, all the time, etc?

Mine is running great 21mpg on a short (sub 5 mile from cold) trip and no sooty exhaust. Just this annoying random vibration on the motorway at light throttle.. doesn't happen all the time. Sometimes it feels like a misfire (running on 5 cylinders) or not too unlike a propshaft out of balance. Other times just minor like a wheel buckle or balance.

[frenchi]

Originally Posted by Dormermike

Can you elaborate on the symptoms that you saw please? Did it happen only when hot, all the time, etc?

Mine is running great 21mpg on a short (sub 5 mile from cold) trip and no sooty exhaust. Just this annoying random vibration on the motorway at light throttle.. doesn't happen all the time. Sometimes it feels like a misfire (running on 5 cylinders) or not too unlike a propshaft out of balance. Other times just minor like a wheel buckle or balance.

It happens on hot engine low rpms 1500-2000 and low throttle and it sounds like a high pressure pipe vibrating. Never happend on full throttle and high Rpms. Was a bit crazy as it doesn't happen all the time..will be perfect for a week and then start vibrating for a day.

One more thing to check - some of these N53 got a vaccum controlled engine mounts and vaccum line or mounts may be damaged !!

[Dormermike]

Originally Posted by frenchi

It happens on hot engine low rpms 1500-2000 and low throttle and it sounds like a high pressure pipe vibrating. Never happend on full throttle and high Rpms. Was a bit crazy as it doesn't happen all the time..will be perfect for a week and then start vibrating for a day.

One more thing to check - some of these N53 got a vaccum controlled engine mounts and vaccum line or mounts may be damaged !!

Ah thank you. I've had this vibration at higher rpm on the motorway perhaps even 5000 rpm at times. At idle it is only at 2000 rpm. Good call on the mounts. All this started when a BMW dealer changed the front wishbones (it's an F10). I had it in France the week before and cruising for hours at cough cough speeds as smooth as glass.