[daniel35d]

My 335d seems to have started to develop some issues now that it's at around 110k miles. I'm kinda struggling to figure out how to describe it properly so others can understand without being present but I'll give it a try.

I've noticed that now when I start to accelerate a bit harder than what one would normally do, the engine can sometimes make a "clacking" sound, but as the rpms and speed increases it stops and the engine sounds smoother again and stays that way untill I release the gas pedal.

It's not crazy loud clacking or anything, but enough for you to hear that something isn't "right". But it has happened once that it sounded worse, which was when I was pulling out from a side road, so it was a sharp left turn while accelerating.

The engine runs fine, doesn't seem to use any oil or anything.

For some reason I'm thinking it might be injector related? Harmonic balancer?

Seems unlikely that it would be something more serious than that?

Anyone got a clue? I don't think it's loud enough for me to be able to record it while driving.

[Mik325tds]

Increased engine noise on left turns or while accelerating harder points to engine mounts. These are pneumatic ones that can collapse when they get older.

[daniel35d]

Originally Posted by Mik325tds

Increased engine noise on left turns or while accelerating harder points to engine mounts. These are pneumatic ones that can collapse when they get older.

This can cause increased clacking sound? It's mostly present in the beginning, the sound quickly dissapears as the speed increases.

But my engine mounts can indeed be bad. Been told that they get alot of stress due to the torque, especially the passenger side one (turbo side).

I have a vibration at idle that dissapears as soon as I touch the gas pedal. It's not as bad as it was in this video, but it's still present. As you can see the rpm needle is also moving a bit despite me not touching the pedal.

[daniel35d]

bump

[bmw_solid]

Its maybe worth opening up the bonnet and have a good sneak around listening for where the noise is coming from.

If you can, remove the engine cover for even better chances of locating the sound.

It could be that it is just a rattle of something that has gone loose and the RPM fluctuating is something completely different...unless the RPM fluctuating started exactly at the same time since the rattle began.

[daniel35d]

Originally Posted by bmw_solid

Its maybe worth opening up the bonnet and have a good sneak around listening for where the noise is coming from.

If you can, remove the engine cover for even better chances of locating the sound.

It could be that it is just a rattle of something that has gone loose and the RPM fluctuating is something completely different...unless the RPM fluctuating started exactly at the same time since the rattle began.

I don't think the RPM thing is related to the rattle I'm asking about in the first post. That was more related to the guy speaking about engine mounts.

Removing the cover wont help me locate a sound that (to me) is mostly present while driving tho.

[bmw_solid]

Originally Posted by daniel35d

I don't think the RPM thing is related to the rattle I'm asking about in the first post. That was more related to the guy speaking about engine mounts.

Removing the cover wont help me locate a sound that (to me) is mostly present while driving tho.

A very common cause of rpm fluctuation is a bad or dodgy MAF/MAP sensor. I also believe a bad injector can cause issues with RPM as well...maybe some injector cleaner additive (good quality) could clear out any blockages within the injector(s).

My 330d fluctuates on idle but with a slight shake...no vibration or clacking sounds. I think it could be a MAF or a injector....I have INPA so at some point will connect my laptop to the car and check what the Injector and MAF sensor values are...I understand they should be in the green zone for starters...

[daniel35d]

Originally Posted by bmw_solid

A very common cause of rpm fluctuation is a bad or dodgy MAF/MAP sensor. I also believe a bad injector can cause issues with RPM as well...maybe some injector cleaner additive (good quality) could clear out any blockages within the injector(s).

My 330d fluctuates on idle but with a slight shake...no vibration or clacking sounds. I think it could be a MAF or a injector....I have INPA so at some point will connect my laptop to the car and check what the Injector and MAF sensor values are...I understand they should be in the green zone for starters...

I did use some additive a couple months ago. Didn't really notice a massive difference.

But I still feel that the engine is a bit more noisy both at idle and while driving than it should be.

A friend of mine has INPA and some other softwares so I can ask if I can borrow that and look at some values.

[bmw_solid]

Originally Posted by daniel35d

I did use some additive a couple months ago. Didn't really notice a massive difference.

But I still feel that the engine is a bit more noisy both at idle and while driving than it should be.

A friend of mine has INPA and some other softwares so I can ask if I can borrow that and look at some values.

Yes, that would be a good idea.. I am not sure exactly what to look out for so if anyone here can give exact advice on what the values should be for the injectors and MAF/MAP sensor that would be a good starting point. I know that INPA gives a green and red (?) zone of the operating values but I think sometimes if for example an injector has a value which is in the green zone but at the border line, that could possibly mean a issue as well... Hopefully someone with more knowledge can advise on this. Or alternatively, you could do a search on this forum regarding what the injector and MAF values should be as a starting point.

If all looks good, there could be other causes also but this would be a good starting point for sure.