BMW E90 accelerating makes revs jump

jonniebgood1

I have a quick query about an 09 320d car that my wife recently got.
When driving normally the revs are consistent and as would be expected. However I was driving it properly for the first time last week and when accelerating hard the rev counter jumps higher and then comes back after a second or 2. The car sounds like an automatic when doing this. My query is whether this is a problem or is it related to the efficient dynamics, i.e. is there an internal shift related to fuel economy?
Thanks for any help.

Matt Simis

What gearbox.. kinda crucial info! Sounds like the clutch is slipping, the revs climb unhindered till it grabs it again. Presume the car isnt actually gaining speed when the revs are climbing like that?

What mileage?


PS: Not sure what you mean by sounds like an automatic, a gearbox type doesnt change a cars sound, engine or exhaust note.

jsd1004

jonniebgood1 wrote: »

I have a quick query about an 09 320d car that my wife recently got.
When driving normally the revs are consistent and as would be expected. However I was driving it properly for the first time last week and when accelerating hard the rev counter jumps higher and then comes back after a second or 2. The car sounds like an automatic when doing this. My query is whether this is a problem or is it related to the efficient dynamics, i.e. is there an internal shift related to fuel economy?
Thanks for any help.

clutch?

jonniebgood1

Matt Simis wrote: »

What gearbox.. kinda crucial info! Sounds like the clutch is slipping, the revs climb unhindered till it grabs it again. Presume the car isnt actually gaining speed when the revs are climbing like that?

What mileage?


PS: Not sure what you mean by sounds like an automatic, a gearbox type doesnt change a cars sound, engine or exhaust note.

Mileage is 60K

Gearbox is 6 speed manual.

What I mean by sounding like an automatic is in the way an automatic drops a gear if you slam on the accelerator. This car is a manual and the change in revs happens when the accelerator is pressed fully. It is like for a change of driving style and the car accelerates while this is happening.

I dont think its the clutch as it happens when in any gear not relating to changing gear.

af_thefragile

Sounds like slipping cluctch.

It does happen in gear. As you accelerate, the clutch looses friction, it slips, the engine revs, the cluctch then gains back friction and the revs drop back down.

jonniebgood1

af_thefragile wrote: »

Sounds like slipping cluctch.

It does happen in gear. As you accelerate, the clutch looses friction, it slips, the engine revs, the cluctch then gains back friction and the revs drop back down.

Perhaps. Would the car continue to accelerate with this.

bryaner

jonniebgood1 wrote: »

Perhaps. Would the car continue to accelerate with this.

It would but not nearly as quick as it should..

testarossa40

jonniebgood1 wrote: »

I dont think its the clutch as it happens when in any gear not relating to changing gear.

In fact a slipping clutch behaves exactly like this. I'd be concerned that the DMF is not far behind either (normally fails long before a clutch plate). Depending what you plan to do about it you MIGHT want to consider getting the DMF pre-emptively replaced as a pair despite the added expense. Not cheap either way...

Wheelnut

I think it's a slipping clutch and I drive an '09 320d 6speed manual. There are no efficient dynamics internal shifts or anything else, it's just a six speed manual gearbox with old-fashioned mechanical cog wheels. Unfortunately it's got a dual mass flywheel (DMF) which may need to be changed and will add to the cost.

Matt Simis

Whats the clutch test again? IRC sit in the car stationary (foot and hand brake on) and put it in a high gear (3rd) and let the clutch pedal out slowly. If the engine starts to stall, the clutch is biting. If the engine doesnt really stall (or does it slowly) then your clutch is f-ed.

http://www.autoeducation.com/blog/drivetrain/how-to-check-your-clutch/


Pretty ****ty to happen at only 60k miles though.

Duff

Clutch went on my sisters 08 320d after 55k. Same symptoms.

thecomedian

The clutch is slipping, the very same thing happen to me a few months back in a golf. It revs up really quickly, after a few seconds it drops back to normal. I only noticed it when I was driving hard.

jonniebgood1

Thanks for all the advice, its a trip to the garage so! Its still under its resale warranty so not all bad.

bazz26

jonniebgood1 wrote: »

Thanks for all the advice, its a trip to the garage so! Its still under its resale warranty so not all bad.

Generally a clutch would be considered a wear and tear consumable and not covered by warranty unless it was proven to be defective. Given that the car was only bought recently though you may get some satisfaction.

JHet

bazz26 wrote: »

Generally a clutch would be considered a wear and tear consumable and not covered by warranty unless it was proven to be defective. Given that the car was only bought recently though you may get some satisfaction.

Would be very surprised if he didn't.