Rough Idle and Misfire

[Z4JB]

Have you cleaned the Idle Control Valve?
Sits behind the Disa so that'll have to come off again.
Electrical connector on the front and the small hose from the inlet pipe goes to one side of it.
The other side is a push fit into seal. So just be careful when you put it back in.
Take it out and see if the valve moves as you twist it around. If not, a hefty dose of cleaner and make sure it comes loose and rattles about.

I've taken it off tonight, could definitely have done with a clean, you were right. Even when having cleaned it with carb cleaner, the valve inside was hardly moving. I have ordered a new part, I believe it is an OEM Bosch spec ICV. Car is idling better now however still not perfect, hopefully given the improvement a new ICV will fix the issue.

 

[enuff_zed]

Have you cleaned the Idle Control Valve?
Sits behind the Disa so that'll have to come off again.
Electrical connector on the front and the small hose from the inlet pipe goes to one side of it.
The other side is a push fit into seal. So just be careful when you put it back in.
Take it out and see if the valve moves as you twist it around. If not, a hefty dose of cleaner and make sure it comes loose and rattles about.

I've taken it off tonight, could definitely have done with a clean, you were right. Even when having cleaned it with carb cleaner, the valve inside was hardly moving. I have ordered a new part, I believe it is an OEM Bosch spec ICV. Car is idling better now however still not perfect, hopefully given the improvement a new ICV will fix the issue.

Fingers crossed its that simple

 

[Bahnstormer]

OK, adding my experience on this as I found this page when I had a rough idle/misfire problem. (2008 Z4 Coupe 3.0si at about 90K Miles)

I am a wannabee home mechanic. I say 'wannabee' , as I always get something wrong ! (And have to call a proper mechanic to dig me out of the holes I create for myself !)

My Symptoms:
> An alarming metallic knocking sound (A very bad end of engine sound !!!)
> Yellow Engine Light on dashboard
> Rough Idle
> Definite misfire when driving (though still runs on 5 cylinders)

> possibly related oil leak I suspect is from the 2 VANOS solenoid O'rings (oil on front of engine block, under )

However, after doing a service (Oil, plug, filter, cabin filter-which was dated 2011 so needed a change !),I had a mobile mechanic come round plug his diagnostic into the OBD Port.

> This showed a misfire on cylinder 2
> Changed the coilpacks from cyl 1 to cyl 2 (or you could ue any other cylinder)
> Mechanic reset all faults
> Drove up and down the road.
> Yellow Engine light came back on andfault has now moved to Cyl 2 - Bingo - Fault found (Cyl 1 coilpack faulty)
> Ordered 6 x Delphi GN10571-12B1 coilpacks which came in at £129 (or £400 from BMW) - No point in replacing and getting the same fault from the other coilpacks as they get older !, and a relatively cheap fix.

Will report back here when I fit them, but am expecting this to fix the fault. Plus will be replacing the 2 VANOS Solenoids in the near future (BMW Doctor online says to replace and not to just try cleaning them as this never solves the problem)

Great video on Youtube from BMW Doctor , on the 3 things to check when rough running : Coilpacks, VANOS solenoids, DISA Valve flaps. [youtube]https://www.youtube.com/watch?v=rMLwQPhhEsU[/youtube]

I may look a the DISA Flaps , but they are not broken so not fixing

 

[Bahnstormer]

So.........

6 Delphi Coilpacks arrived from Autodoc , and have been installed . No point in just changing one as the rest will fail eventually, and the car is running great , and feels like it has much more power.

Full service performed including pollen filter , full of leaves and last changed in 2011 !!!!, Plugs last changed in 2014 !, and coilpacks installed .....by the factory in 2007 !!!!! - Think I'll just service it myself from now on !

Handy little video on resetting the 'next service due' notification (and reset earning lights as far as I am aware) on the dash here > https://www.youtube.com/watch?v=DfHlP5mEQkk&t=3s

Small oil weep on the front of the block from the VANOS solenoids, so will be swapping them for a pair of Pierburg OEM replacement items shortly with some new rubber O-rings. I ordered some from e-bay, and they look like they came from a supermarket multipoack, so will be swapping them for proper BMW items (no pint in skimping on these, as I would imagine the cheapie ones online are not brilliant !

Adaptive throttle reset tonight before a test drive.