Strange Z4M engine problem... Who has an idea?

[Franzino]

Really occasionally my Z4M starts doing this when I start my car (when engine is cold). The car has been 3 times to an official BMW garage and the problem is still here. Last time it occurred was a month a go and now today again (when starting in the morning).Car sleeps in a garage (not outside). So it only shows occasionally, with is really annoying because I can not show the problem live to my BMW garage. They can only read the error codes and see that the yellow engine light is burning. When the problem occurs, I have to stop en start the enigine about 3-4 times en then is starts, runs and sounds normal...

[vimeo]62609083[/vimeo]

[vimeo]62609082[/vimeo]

Vimeo: http://vimeo.com/62609083 and this one http://vimeo.com/62609082

 

[dalecan]

What does it do? What are the signs / symptoms? Hot / cold engine make a difference?

 

[Machine monkey]

I had this exact problem on my 3.0l. I cant remember the fault code something like p108?

For me it was the throttle body. A little plastic gear had a broken tooth. £250 part and fitted it my self. But mine is not an //M??

There is a sensor on the throttle body just make sure its seated correctly and clean. Otherwise look into the throttle position sensor on the loud pedal.

Sorry about the problem. Hope you get it sorted.

I am not saying this is it either just might be of help

 

[Toe-side]

Does it only exhibit this behaviour when cold?

 

[goon]

Mine has done this several times its a real nuisance you cant drive it. Checked it with my code reader gives me camshaft position sensor fault. Sometimes after this the car will drive with a lack of power feeling flat but still revving freely.

 

[sammyz]

I'd have a good look on M3 forums to see if this has happened on the E46 M3.
I seem to recall a friend's Audi that did something similar and that was the camshaft position sensor as Goon suggests. Likely electrical and various sensors seem prone to fail on these engines.

 

[dalecan]

What does it do? What are the signs / symptoms? Hot / cold engine make a difference?

Am I missing something, as I can't see the explanation of what is wrong? I'm using an ipad so I'm just wondering if something is not viewable that the OP has listed! :tumbleweed:

 

[ga41]

What does it do? What are the signs / symptoms? Hot / cold engine make a difference?

Am I missing something, as I can't see the explanation of what is wrong? I'm using an ipad so I'm just wondering if something is not viewable that the OP has listed! :tumbleweed:

There are 2 attached vimeo videos showing the problem. This one http://vimeo.com/62609083 and this one http://vimeo.com/62609082

 

[Franzino]

What does it do? What are the signs / symptoms? Hot / cold engine make a difference?

What does id do: It makes the engine rev on it's own when I start the car (see the video).
Symptoms: Nothing more to tell about actually, then what I posted in the opening post.
Hot / Cold: Only happens occasionally when engine is cold.

 

[bcworkz]

What trouble codes are showing up? As mentioned, this sounds like a sensor issue. When cold, electric bits shrink, opening a fault. Once warm, the bits expand, closing the fault and acting normally. Sometimes you can induce the fault for testing by removing the part and placing it in a freezer for a while. But you need a clue to which part to test, hence the trouble codes. Avoid replacing parts based on trouble codes without independent confirmation.

 

[Vincent_Schweiz]

I had the exact same engine behaviour when I changed the throttle position switch (the one on the throttle actuator below the intake manifold) and forgot to plug the connector. The idle was "bouncy" like yours with a cold engine. I stoppped the engine, plug the connector and the issue was gone.

 

[Toe-side]

I had the exact same engine behaviour when I changed the throttle position switch (the one on the throttle actuator below the intake manifold) and forgot to plug the connector. The idle was "bouncy" like yours with a cold engine. I stopped the engine, plug the connector and the issue was gone.

That ties in with machine monkey's diagnosis on the throttle body problems.
I thought it might be a temperature sensor fault changing the injection/fuel mixture randomly. It would be good to get a fault code. Might have more chance taking it to an independent?

 

[dalecan]

What does it do? What are the signs / symptoms? Hot / cold engine make a difference?

Am I missing something, as I can't see the explanation of what is wrong? I'm using an ipad so I'm just wondering if something is not viewable that the OP has listed! :tumbleweed:

There are 2 attached vimeo videos showing the problem. This one http://vimeo.com/62609083 and this one http://vimeo.com/62609082

Thanks, they're not showing on my iPad.

 

[ga41]

Thanks, they're not showing on my iPad.

You can use the Vimeo application https://itunes.apple.com/us/app/vimeo/id425194759

Back to the subject at hand, i really wish i could help you Franzino, perhaps take it to a reputable independent garage for evaluation?

 

[ChawenHalo]

Hope you get it sorted; Does not sound too serious though perhaps just some electrical gremlin or mechanical adjustment. Get everything sorted by an M specialist and they should know what it is.

 

[Franzino]

When't back to the dealer for the fourth time... They did some new programming of the the throttle position switch and so far so good

 

[Woody]

A valve clearance check and possible shim replacements might help things too...

 

[jimmybell]

Sounds like an astra i used to own when the idle control valve was dirty (controlling air intake at idle).. did exactly the same bouncing revs... just a bit slower!

 

[ChawenHalo]

A valve clearance check and possible shim replacements might help things too...

Good point. Mine starting to get a bit grumpy too. With plenty of hard use neither valve clearance and shimy were done in the last service so I'll get it done soon. WIll report back.

 

[goon]

Well I had mine serviced and cam sensor changed but 2 weeks after and its misfiring and poor running again,not happy.