Rough Idle

[andyf1140]

Looking for some advise on where to start...

The Z has a rough idle, no other symptoms just a bit rough, you can feel it through the seat. I cleaned the vanos valves when I did the valve cover gasket but it made little difference. The coil packs were all replaced over the last year, and the spark plugs were last changed at 64,000 and it's currently on 92,000. There was a little oil in the eccentric cam sensor but there are no codes being reported by the ECU, well at least the check engine light is not on. I'm wondering if it's going to be worth replacing the plugs even though they have only done 30,000 miles, I don't know what brand was used.

Thoughts?

[Smartbear]

Unplug the eccentric cam sensor & see if the rough idle disappears, should tell you if it’s at fault-it’s an expensive item unfortunately
Rob

[ph001]

What happens when you blip the throttle lightly from idle? Does it rev cleanly or stutter?

What engine do you have?

[andyf1140]

it's a 2.0i engine. It seems to pick up ok when blipped, but it does seem a bit lumpy when accelerating through the rev range like it's got a bit of a flat spot but when it's over 3k it pulls really well. It also hunts a bit when cold if it's left to tick over. I can't see that there is anything major wrong with it as it returned 44mpg on a motorway run at the weekend.

[andyf1140]

Unplug the eccentric cam sensor & see if the rough idle disappears, should tell you if it’s at fault-it’s an expensive item unfortunately
Rob

Is it a dealer only part I couldn't find it on ECP or Andrew Page?

[Smartbear]

Unplug the eccentric cam sensor & see if the rough idle disappears, should tell you if it’s at fault-it’s an expensive item unfortunately
Rob

Is it a dealer only part I couldn't find it on ECP or Andrew Page?

Available on eBay, I’ve heard for a lot less money from Germany if you know the sensor part number
Rob

[andyf1140]

Unplug the eccentric cam sensor & see if the rough idle disappears, should tell you if it’s at fault-it’s an expensive item unfortunately
Rob

Is it a dealer only part I couldn't find it on ECP or Andrew Page?

Available on eBay, I’ve heard for a lot less money from Germany if you know the sensor part number
Rob

So you know what the next question is going to be

[Smartbear]

Is it a dealer only part I couldn't find it on ECP or Andrew Page?

Available on eBay, I’ve heard for a lot less money from Germany if you know the sensor part number
Rob

So you know what the next question is going to be

So does unplugging the sensor stop your rough idle?
Rob

[andyf1140]

I've not had chance to look at it yet. I plan to do a full service on Saturday. The plugs were last changed at 62000 and it only cost 160 including oil and filters so I don't think they could have used quality plugs. Anyway I'll test the sensor while I'm doing the service.

Thanks

Andy

[Scooba_Steve]

I believe the issue is not that the sensors fail, but the seal does allowing oil in. Not sire the seal can be replaced with the sensor in situ

[andyf1140]

I didn't think that the sensor could be serviced, I thought that it was a replace it deal. To "test it" is it safe to unplug it while the engine is running or should I unplug it and then start the engine?

[mjennings23]

http://www.realoem.com/bmw/enUS/select

For part numbers

[road warrior]

bump..

i have the same issues.. erm... what is an eccentric cam sensor ?? and where does it live ?
i will add i cleaned the engine bay with gunk and water as the the prev owner didnt look after it and it was filthy but had a happy sounding engine, so maybe water in a connector or 2 maybe ? fires on 4 nicely when driving. Although when Mike saw it he commented that it was a couple of cylinders short... 2.0i ya see...

[andyf1140]

It's in the cam cover just behind the oil filler cap. I would suggest getting some electrical cleaner and giving the contacts a good clean and dry out. What I have found is that mine runs better on regular unleaded rather than super which is counter intuitive.

[road warrior]

good idea, a bit of isopropelene works wonders having said that mine seems to have settled down and it is sounding sweet, and was happy enough till today when i was forced to follow a supercharged jag burbling down the road