Strange Boost Issue

[s3 addict]

Hi, I have a 2001 AMK S3 and I'm having a job finding this boost issue. Basically the car will boost if I feather the throttle a bit first, You can here the change in pitch from the turbo. But if i put my foot down straight away it wont boost until i'm above 4-5k revs. This seems more of an issue in 1st and 2nd gear. I've replaced the N75 valve and this made no difference, I've disconnected the MAF and it made no difference. I do have a leak on my crankcase breather pipe but I'm not sure how that would effect it? I've plugged in my vag reader and no codes were found. The only other issue I have is the lateral acceleration sensor is intermittently failing but that cant have any effect on the turbo surely? Could this be an issue with the waste gate actuator? The boost hoses seem fine. Any help would be very much appreciated.

 

[s3 addict]

Can nobody offer any advice??

 

[<tuffty/>]

What VAG reader you using? unless its VCDS (VAGCOM) then there is no guaranty that all codes will be read...

PCV leaks (such as you say you have) could well be the problem... depending where its leaking it could manifest into a big boost leak..

Ideally you need to check any/all pipes and hoses for leaks (smoke tests are ideal for this) and any leak should be fixed regardless...

Then get hold of VCDS or someone with it at least and do a full scan followed by checking a few logging blocks in the engine module... block 032 is fuel trims and high percentage value in the first field indicates a potential vacuum leak...

Boost gauge (even just temporarily plumbed in) would be useful too

<tuffty/>

 

[smokiedee]

a major loss in my power came from the breather pipe from the inlet manifold had a 2cm split in it. since then running smooth but loss power again so gonna try changing the pcv tomorrow

 

[s3 addict]

Thanks for the replies, I've managed to fix the PCV issue but it's not made any difference. The boost is still all over the place, I have noticed this is only really after the engine warms up a bit. I'm thinking boost leak. I do have Vag.com but not a registered version so can't look at all the blocks. I just want it to finally run as it should!!!