faulty DV 710 A

[arranstone]

I have been suffering a running issue with my S2 for some time now and have been slowly narrowing down the problem. Having replaced the plugs, new lambda sensor, new coil pack conversion courtesy of error 404 (brilliant OEM looking harness thanks!), and new red Beru coilpacks. I was still getting this strange surging at about 2000-3000 rpm. On full boost no problem. Had double checked all boost hoses (silicon) and clamps. Today I decided to remove the Bosch DV valve. I tested it by pressing down on the valve with a 8mm socket and1/4 extension and then placing my thumb over the small nipple valve and removed the socket. The valve returned straight away. So decided to take it apart to examine the rubber diaphragm. This is what I discovered.

IMG_20141011_110919.jpg

I presume this is the cause of my running issue. Any advice would be much appreciated.
I have tried to source a new Bosch 710N but been told they are NLA.

[UrS4boy]

BPV info as it relates to UrS Motronics

The 710N (06A145710N ) is still available through the dealer and aftermarket systems. It's just that Bosch sold the rights off to a third party, Kayser, who is now making them.

http://www.ecstuning.com/Search/SiteSearch/06A145710N/

http://forums.quattroworld.com/s4s6/msgs/20994.phtml

[Colesy]

I got one from here last month:

http://www.germanautopartsdirect.co.uk/p12/DUMP-VALVE-06A145710N-now-06A145710P/product_info.html

Must have recently been superseded. I guess the P version would be ok though?

[newsh]

I bought 2 from TPS very recently

[andyg plym]

I have a spare Bosch unit if you want to try it

[Error404]

If you can buy a used Bosch 710N, they are very robust and apparently the Kayser ones are poor quality

[arranstone]

Will try TPS Monday. Have been told that Bosch DV 06A145710N has now been superseded by 06A145710P. Is this correct?

Also is it worth replacing the N75 when I fit a new DV. My N75 is looking old and rusty!

[4WDrifter]

Will try TPS Monday. Have been told that Bosch DV 06A145710N has now been superseded by 06A145710P. Is this correct?

Also is it worth replacing the N75 when I fit a new DV. My N75 is looking old and rusty!

Does anyone have any thoughts on this?

[UrS4boy]

Does anyone have any thoughts on this?

Old and rusty does not mean broken inside, where it counts. Save your dosh until it fails.

Or buy a new shiny one now.

[arranstone]

Tried TPS in Plymouth today and part is NLA. (Bosch 034 145 710 N). Then tried eurocarparts, they said the could get hold of one but wanted £106 . Said no thanks. Will try Audi main dealers tomorrow, if no luck there then don't know where to find one!

[Error404]

Arran I PM'd you with links where to buy the N75 and bypass valve

[4WDrifter]

Did you get a new dump valve fitted? Can you describe your problem in a little more detail please as I think I have the same issue maybe.

[UrS4boy]

BPV info as it relates to UrS Motronics

Did you get a new dump valve fitted?

Sorry but these are not "dump" valves that "dump" boost to atmosphere. They are by-pass or recirculation valves or "Over-run cut-out" valves so the turbo a) does not stall and b) is kept spinning in the correct direction during throttle off gear changes so the spool-up on throttle is not lagged even more.

http://forums.quattroworld.com/s4s6/msgs/20994.phtml

[4WDrifter]

Thanks for this. I'm sorry to say that I'm completely green when it comes to our engines, but I can see how this could be causing my symptoms. I can still get from A to B okay in the car so I'm not too concerned but I don't want to start replacing bits unnecessarily and then maybe create a different issue.
My symptoms are that when I'm driving at about 30mph in town, I'm in 3rd gear because that's how I try to keep under the speed limit, thus avoiding points on licence, the car doesn't maintain a constant note or " thrust " it seems to pull a bit and then slow off again. I can't remember if it has always done it, I've owned the car about a year and a half, and initially I thought it was a fuel supply issue so I replaced the original fuel filter and I thought it had cured the problem, then there it was again.
Any thoughts anyone?

[4WDrifter]

Sorry forgot to say that the revs are 2500-3000 ie. just before turbo comes in