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Rough idle and terrifying knocking noise…

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Thadeus1991
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Rough idle and terrifying knocking noise…

Post by Thadeus1991 » Sun Jun 13, 2021 10:52 pm

Hey guys,

Came back from Oxford today and noticed a rough idea at traffic lights paired with some horrible sounding knocking noises from the engine bay.

I had the rough idle a couple of times before (but it went away) and mentioned that to Ross at RBM a couple months ago. At the time, they did an error read and the only thing they found was a DISA valve error that occurred once and not again. Ross recommended to not do anything at that point and just keep an eye on it (as the N52 DISA does not lead to catastrophic engine failure apparently).

I’m attaching two videos - does anyone know it this resembles the symptoms of a failing DISA valve or might it be something else? It sounds pretty rough so I’m very worried.

I don’t have a code reader, so can’t check and I’ve already emailed RBM to get them to look at that. So I’m pretty much hoping to get some peace of mind from here 🥲🥲

Links to the videos (hope this works):
Rough Idle Engine Bay
Rough Idle Tachometer
2006 e85 Z4 - 2.5i Montego Blue
-----------------------------------------
2002 e46 330ci convertible (gone)
2006 e85 Z4 - 2.5i (gone)

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Rockhopper
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Rough idle and terrifying knocking noise…

Post by Rockhopper » Mon Jun 14, 2021 8:08 am

Don't know what the noise it but if it was mine I wouldn't be driving it. Get it recovered to your repair person.

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wonkydonkey
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Rough idle and terrifying knocking noise…

Post by wonkydonkey » Mon Jun 14, 2021 5:09 pm

Could that be a flywheel that's expiring/expired? Hard to tell from the vids.
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Thadeus1991
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Rough idle and terrifying knocking noise…

Post by Thadeus1991 » Mon Jun 14, 2021 8:53 pm

Well, it’s being towed to RBM tomorrow, so fingers crossed it’s nothing too major 🤞🏻
2006 e85 Z4 - 2.5i Montego Blue
-----------------------------------------
2002 e46 330ci convertible (gone)
2006 e85 Z4 - 2.5i (gone)

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Thadeus1991
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Joined: Sun Nov 19, 2017 7:38 pm
Location: Streatham, London

Rough idle and terrifying knocking noise…

Post by Thadeus1991 » Fri Jun 18, 2021 6:38 pm

Just thought I’d update you all on the result:

As it turns out it was 2 separate things wrong with the car. I needed a new DISA valve as well as a new ignition coil and spark plugs.

Came at the hefty price tag of £575 but at least it’s all good again and ready for the sun ☺️☺️
2006 e85 Z4 - 2.5i Montego Blue
-----------------------------------------
2002 e46 330ci convertible (gone)
2006 e85 Z4 - 2.5i (gone)

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bigwinn
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Rough idle and terrifying knocking noise…

Post by bigwinn » Fri Jun 18, 2021 7:08 pm

Glad to hear It’s fixed!!
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