Vano noise? Flat spot and changing idle

[Funkyflynz 151]

Hey team,  have a weird issue.

when idling... When idling the rpm will jump from 1200 (cold) down to 500, the car sounds like its labouring for a while (10-30sec) then jump back up to 1200.  When hot it will drop down to 400.  

When driving...whilst driving the car hits flat spots randomly, it doesnt cough or splutter rather it just becomes unresponsive like there nothing there.  Engine tone changes.  
 

Poking around i seem to have some noise coming from the vanos, not sure if this is normal or signs of an issue?  Related or not?

 

Any thoughts/advice would be appreciated. 

[sweetm3 180]

Hi Lee

No it doesn't sound good, have you tried the long screw drive to your ear. This will help pin point the area of the noise.

[Funkyflynz 151]

52 minutes ago, sweetm3 said:

Hi Lee

No it doesn't sound good, have you tried the long screw drive to your ear. This will help pin point the area of the noise.

Thanks, yes, it sounds like its from the vanos.  Might be the typical vanos rattle but ive not heard it before.  Have a vanos rebuild planned and part ls on the way.  But a rattle should t be causing these flat spots. 

[M3AN 4016]

Remove and test the throttle position sensor, cleaning mine fixed my erratic idle. As for the flat spots, check for any ECU codes, especially hidden (secondary) codes, you'll need to use INPA or DIS for that, not a consumer code reader.

 

[Funkyflynz 151]

2 hours ago, M3AN said:

Remove and test the throttle position sensor, cleaning mine fixed my erratic idle. As for the flat spots, check for any ECU codes, especially hidden (secondary) codes, you'll need to use INPA or DIS for that, not a consumer code reader.

 

Thanks, will give that a try.   I need to get on to INPA . Been putting it off as i prefer spanners 😂😂

[Chanderpaul 15]

Did you have any luck with figuring this out ?  I am having similar issues with funny idle and some ECU codes.

[Funkyflynz 151]

5 hours ago, Chanderpaul said:

Did you have any luck with figuring this out ?  I am having similar issues with funny idle and some ECU codes.

Ive ordered a new tps and a vanos rebuild kit.  Will update once ive tried done each

[Funkyflynz 151]

On 6/11/2021 at 2:12 PM, Chanderpaul said:

Did you have any luck with figuring this out ?  I am having similar issues with funny idle and some ECU codes.

Hi, update for you- TPS didnt change anything, and the car sat for a year neglected (big sad face) but good news, im able to send some more time on it, ive replaced to coils that were faulting and cleaned the MAF, this made a huge difference, theres still a little stumble at times and the MAF is still throwing a fault code.  

Ive now ordered a new MAF.  Interesting talking to a highly regarded BMW/Targa mechanic explaining what im seeing he said it could be a number of things but that a bad MAF is the most common cause of issues by far.

 

[Chanderpaul 15]

Good to hear that coils and cleaning MAF made some difference. Where did you order your coils and new MAF from?

[Funkyflynz 151]

On 1/31/2023 at 6:13 PM, Chanderpaul said:

Good to hear that coils and cleaning MAF made some difference. Where did you order your coils and new MAF from?

From fcp euro.   

[Funkyflynz 151]

Started on the vanos rebuild, man this s50b32 sure is more complicated than the s54.   Anyway things seems to be going well, apart from this “stop disk” which im not 100% sure where it goes - doh!  Any help wpuld be appreciated 

[M3AN 4016]

Ugh, that brings back memories... all that orange gunk is such a PITA.

The stop disk goes on top of the needle bearings, between them and the big circlip.

 

[Funkyflynz 151]

7 hours ago, M3AN said:

Ugh, that brings back memories... all that orange gunk is such a PITA.

The stop disk goes on top of the needle bearings, between them and the big circlip.

 

Thanks mate.   Let me take this opportunity to thank you for your contributions to BMW forums, ive come across a lot of your posts on here and the UK forum, its been a huge help.   Much appreciated 🤙🏻🤙🏻