N52 - 3.0si - jerkiness

[RyanB88]

Hi

Right time to sort this once and for all!

Symptoms: When accelerating at low revs/ in traffic on a cold start 99% of the time and occasionally when the engine is warm, the car will shake backwards and forwards, almost as if I'm on and off the brake or the clutch. It's quite violent. Then I dip the clutch in and Rev it a little bit and it goes away once you're off on the move

The other (maybe unrelated, maybe related) symptom is that the idle is very lumpy and can sometimes cause the car to shake left and right on tick over, with the revs visably rising up and down for no reason abnormally so

I've replaced - spark plugs, air filter, engine oil, Ccv, vanos solenoids.

I have no fault codes

Can anyone please suggest what this may be as it's ruining an otherwise amazing car!

Thanks in advance

 

[Smartbear]

Hi, valvetronic eccentric shaft sensor can cause bouncing unsteady idle but it's not cheap
Rob

 

[RyanB88]

Hi, valvetronic eccentric shaft sensor can cause bouncing unsteady idle but it's not cheap
Rob

How much am I looking at roughly? Is it DIYable?

If this was the issue, would it not show up fault codes?

 

[Smartbear]

Hi, valvetronic eccentric shaft sensor can cause bouncing unsteady idle but it's not cheap
Rob

How much am I looking at roughly? Is it DIYable?

If this was the issue, would it not show up fault codes?

Stupot had the same symptoms I seem to remember, it's expensive at around £400
Diyable as well, I think the sensor leaks oil when it's fubard & disconnecting it gives a steady idle back proving the sensor is knackered.
Rob

 

[RyanB88]

Hi, valvetronic eccentric shaft sensor can cause bouncing unsteady idle but it's not cheap
Rob

How much am I looking at roughly? Is it DIYable?

If this was the issue, would it not show up fault codes?

Stupot had the same symptoms I seem to remember, it's expensive at around £400
Diyable as well, I think the sensor leaks oil when it's fubard & disconnecting it gives a steady idle back proving the sensor is knackered.
Rob

OK thanks for this Rob. Any ideas where the sensor is or how I can locate it to check it's condition/disconnect to see if that's the issue?

 

[Smartbear]

Hi, I believe it exits from the cam cover :?
Rob

 

[Chris1981]

I too suffer from this issue... but very rarely, maybe once a week or fortnight and given it's my daily that's not very often! I usually associate it with pulling away and not having enough accelerator! Having cleaned the MAF I felt an improvement but might investigate the eccentric camshaft sensor too!

I've had a look at mine and there's no leaks but may try leaving it unplugged if it plays up again!

Ryan, this is the one you're looking for (as long as image comes through!)... DIYable but a big job as it's valve cover removal, and as we both have the metal valve covers it's new bolts and gasket from BMW as they're single use on ours! :thumbsdown: