Intermittent Boost / Overboost

[TanyaS3]

Hello!

Its been a while...... but I need some help please.............

My S3 has a problem with intermittent boost. It will either not boost at all or massivley overboost to 25lb !!!!. Ocasionally it will boost normally. I also notice that the wastegate seems to chatter different amounts randomly (either a very small amount or fairly audible). The ambient temprature seems to make no difference. Has anyone else had this problem? Any help would be appreciated.

Thanks
Tanya

 

[Sandip]

Could be the N75 valve, dumpvalve or N249

 

[TanyaS3]

Thanks.

I have spoken with Audi parts regarding the two valves. N75 and N249 seem to denote a number of different solenoid valves in the system. Is there anyway to figure out which valves I would need to replace ?. The car has been checked on with a diagnostic tool. The system displays : -

01 - Engine electronics
8N0 906 018
1.8L R4 5VT
Coding 5610

value above maximum charge pressure

Any info much appreciated

 

[S3 Paul]

Idealy you need to use vag com to check/ log the figures,
Where abouts are you??
I changed most of the control solanoids on my car ( it isnt cheap to just start changing things in hope )

 

[TanyaS3]

Hello, changed a part, I think N75 located at top of engine under cover and it all works fine and is holding boost nicely
thanks for your help and advice
Tanya

 

[ianysm]

sounded like dv problem. This is at top of engine.

 

[S3Steve]

The N249 valve is the one ontop of the engine under the cover, the dv and N75 are both located on the tip.