lumpy idle on z4 2.0i sport

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ALPHA 3.0i Z3
Joined: Tue 26 Jan, 2016 20:37
Posts: 57

  Z3 roadster 3.0i
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lumpy idle on z4 2.0i sport

Post by ALPHA 3.0i Z3 » Sun 20 Mar, 2016 18:49

Just bought the car drives like a dream but idle I a bit lumpy. I know its a four pot but its not a smooth idle the rev counter skips a bit as well, only a little but noticeable
Any help or advice please.
A
Who says size doesn't matter? After a straight 6 3.0 litre....Its hard to go back .

John Wilson
Joined: Fri 12 Jun, 2009 13:11
Posts: 240

  Z3 roadster 2.0
Location: Diss

Re: lumpy idle on z4 2.0i sport

Post by John Wilson » Sun 20 Mar, 2016 19:43

It could be the idle control valve needs a clean. I had lumpy idle for years wih my Z3 and that completely cured it. My post about it is here
http://www.zroadster.net/forum/viewtopi ... ol#p404881
But, of course, thats for a 6 pot Z3, not yuor Z4, but I believe you have one as well.

Del
Joined: Sat 19 Nov, 2011 18:35
Posts: 2115

  Z3 roadster 1.9

Re: lumpy idle on z4 2.0i sport

Post by Del » Sun 20 Mar, 2016 20:49

1) I would first check for any splits in the MAF sensor/intake rubber bellows – common BMW issue.
2) If you disconnect the MAF sensor and start the car, does the idle improve?
3) Do you have any timing chain noise at idle – a rattle will be more noticeable on a warm engine – a slack chain caused by a weakened tensioner has been known to cause a slightly erratic idle. Certain 2.0 BMW petrol engines (and some diesels) were known for this.

ALPHA 3.0i Z3
Joined: Tue 26 Jan, 2016 20:37
Posts: 57

  Z3 roadster 3.0i
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Re: lumpy idle on z4 2.0i sport

Post by ALPHA 3.0i Z3 » Sun 20 Mar, 2016 22:23

John Wilson wrote:It could be the idle control valve needs a clean. I had lumpy idle for years wih my Z3 and that completely cured it. My post about it is here
http://www.zroadster.net/forum/viewtopi ... ol#p404881
But, of course, thats for a 6 pot Z3, not yuor Z4, but I believe you have one as well.
Hi John yes I have a Z3 as well and have considered doing the ICV.
Thanks I will look at doing both cars, cant hurt for sure.
A
Who says size doesn't matter? After a straight 6 3.0 litre....Its hard to go back .

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