Bad noise from 2.0L engine when releasing quickly the throttle

[penant78]

Hi everyone,

I posted this question a few months ago but I could only manage to have a look this week.

When I quickly release the throttle after revving the engine (standstill or driving), there is a bad noise coming from the engine (see first video).

My first thought (and also my brother in law which is a mechanic) was a failed timing chain tensioner or guide.

Problem is the noise really seems to come from the back of the engine (intake manifold side) even if I know that tracking an engine noise is not easy.

I put a new timing chain tensionner, same noise.
Yesterday I removed the cam cover to have a look at the chain and the guide, but everything seems tight and the guide still in one piece from what I can see (second video)

I don't really know what to search next. Anybody could give me some advice?

[youtube]https://youtube.com/shorts/UHs5yoON_U4[/youtube]

[youtube]https://youtube.com/shorts/3HCiyAMKc98[/youtube]

 

[Jfgoldfish]

Have you tried disconnecting the variable intake actuator to see if that is what is causing the noise?

The chain and guide assembly look fine and likely original, so hopefully no dodgy work has been done on the timing.

I have a complete spare intake manifold for an N46 so give me a shout if you require intake parts.

 

[penant78]

Have you tried disconnecting the variable intake actuator to see if that is what is causing the noise?

The chain and guide assembly look fine and likely original, so hopefully no dodgy work has been done on the timing.

I have a complete spare intake manifold for an N46 so give me a shout if you require intake parts.

Thanks. I will have a look at it. How would the actuator cause this noise?

 

[Jfgoldfish]

Thanks. I will have a look at it. How would the actuator cause this noise?

To be honest, it's a bit of a wild guess.
The video does sound like either chain slap or some sort of plastic 'clacking' noise; the variable intake is quite a substantial moving part inside the intake manifold that could be causing a noise in the area you described. I don't know a whole lot about the system but I know the actuator is easy to disconnect so it's an easy one to rule out.

Do you have a mechanics stethoscope? They can really help pinpoint odd sounds. You can hear components much more clearly and pinpoint the origin of the sound.

 

[penant78]

Thanks. I will have a look at it. How would the actuator cause this noise?

To be honest, it's a bit of a wild guess.
The video does sound like either chain slap or some sort of plastic 'clacking' noise; the variable intake is quite a substantial moving part inside the intake manifold that could be causing a noise in the area you described. I don't know a whole lot about the system but I know the actuator is easy to disconnect so it's an easy one to rule out.

Do you have a mechanics stethoscope? They can really help pinpoint odd sounds. You can hear components much more clearly and pinpoint the origin of the sound.

The noise still the same with the actuator disconnected.
I forgot to say I have the common 2B63 code, which still there after I changed the camshaft sensor.
I've read so much stories about people changing everything without finding the problem.
I've read a similar description to mine on another forum and the problem was a broken timing chain guide. But mine still good.

 

[penant78]

Here is the story I read, where he finally found it was a broken guide:

****6 weeks ago I bought a lovely example of a 320i. The N46 engine has since thrown up a 2B63 fault (exhaust cam sensor) and developed a strange knock / clanging noise when blipping the throttle or releasing the throttle. Feels and sounds like its coming from the inlet manifold however the main dealers and independent garage I use both think its the timing chain.

Has the N46 got a history of timing chain issues? or am I just unlucky?
and could the noise transfer to the inlet manifold. You cant feel it on the block, only the manifold****

 

[Jfgoldfish]

I must say, in the video it does sound like chain slap. The post you have copied in there sounds like a very similar set of symptoms.
The bottom guide does not commonly break, just the top. Your top guide looks to be ok and I doubt the chain could have jumped a tooth without snapping the top guide.
Out of interest though, did you happen to check the timing whilst you had the cover off?

 

[penant78]

I must say, in the video it does sound like chain slap. The post you have copied in there sounds like a very similar set of symptoms.
The bottom guide does not commonly break, just the top. Your top guide looks to be ok and I doubt the chain could have jumped a tooth without snapping the top guide.
Out of interest though, did you happen to check the timing whilst you had the cover off?

I did not check the timing, I think I need some special tools. Anyway if the guide and chain need to be changed, I'll need these tools.