Idle Issue

Z450 · Post by **Z450** » Tue Oct 17, 2023 8:38 pm

Good evening

I have a 2006 BMW Z4MR which has covered around 62,000.

When cold it has a rough idle and feels like it wants to cut out.

This lasts approximately 30 seconds or so and is fine.

Looking through the cars history it has been to Bmw who could not find the issue. It is currently with a bmw specialist who are struggling to find an issue as well. Parts that have been replaced include plugs, coils and injectors. The car is also showing no fault codes.

My question is could this be a VANOS issue and if so who where would you recommend taking the car?

Thank you

Mr Tidy · Post by **Mr Tidy** » Tue Oct 17, 2023 9:08 pm

It sounds like the topic of this thread:- viewtopic.php?t=39891&hilit=hesitation

Z450 · Post by **Z450** » Wed Oct 18, 2023 7:40 am

Thank you Mr Tidy, an interesting read, although sadly there does not seem to be a conclusive answer

beanie · Post by **beanie** » Wed Oct 18, 2023 9:26 am

Does it splutter/misfire when you try to apply throttle during this time?

Mine had a cold start idle problem with the above symptoms which immediately disappeared after the cold start enrichment/warm up cycle. Turned out to be the check valve between the airbox and brake servo. It had got gummed up and needed cleaning. I also cleaned out the oil separator under the rocker cover just in case.

Z450 · Post by **Z450** » Wed Oct 18, 2023 11:04 am

beanie wrote: ↑Wed Oct 18, 2023 9:26 am Does it splutter/misfire when you try to apply throttle during this time?

Mine had a cold start idle problem with the above symptoms which immediately disappeared after the cold start enrichment/warm up cycle. Turned out to be the check valve between the airbox and brake servo. It had got gummed up and needed cleaning. I also cleaned out the oil separator under the rocker cover just in case.

Thank you for the above, yes it does splutter misfire, it’s just for a very short period!

beanie · Post by **beanie** » Wed Oct 18, 2023 12:21 pm

: 6536BC33-81C4-4918-828B-9FC9CD995A99.jpeg (79.5 KiB) Viewed 310 times

I think it was this part

Pipes can be a bit tough to separate but once it’s off give it a shake and see if you can feel something moving inside. A bit of carb cleaner and some shaking should free it up and hopefully resolve things. Mine hasn’t played up since I cleaned it and the oil separator.

Z450 · Post by **Z450** » Wed Oct 18, 2023 5:57 pm

beanie wrote: ↑Wed Oct 18, 2023 12:21 pm 6536BC33-81C4-4918-828B-9FC9CD995A99.jpeg

I think it was this part

Pipes can be a bit tough to separate but once it’s off give it a shake and see if you can feel something moving inside. A bit of carb cleaner and some shaking should free it up and hopefully resolve things. Mine hasn’t played up since I cleaned it and the oil separator.

Thank you for this, really appreciate

beanie · Post by **beanie** » Wed Oct 18, 2023 11:10 pm

You’re welcome, i hope it solves the problem.

I’d also been to a couple of garages about the issue but hadn’t had much luck. As it seemed to coincide with the cold start sequence the general consensus was to delete the SAP-thankfully a local place did a bunch of testing and found the issue before I’d spent a fortune or removed anything.

Fingers crossed for you

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