dump valve problem

[jimmer 22]

hi all, new to the forum, have got a completly standard 2000 reg s3. iv got an intermittent boost problem, if i drive the car up to temperature and then stop the car for about 10 mins to half hour and then drive it again, the car doesnt boost properly. im sure the turbo is spooling but theres no real boost right through the rev range. it feels like it is holding back, almost like the feeling you get when your clutch is slipping. if i then drive the car on the dual carrige way or long road for any amount of time the problem is then gone again, making me think it is temperature related. iv fitted a new maf after reading they can cause problems, but it didnt sort it. this morning i stripped and cleaned the forge dump valve, and did the test of pressing the piston up, and putting your finger over the top valve. in doing this the piston went straight back down. im pretty sure its not ment to do this, but wasnt sure as havent used these recirculating valves before. can anyone help before i buy a new one, and do you think this could be causing my problem, or a completly seperate issue. sorry for the long post, many thanks

 

[G60DAN]

You need to put it on vagcom and what comes up that's where I would start

 

[Madeley]

Have you tried sucking the piston up to see if its working and blowing down the nipple on the side to test for leaks.

 

[jimmer 22]

no not tried that. think its nackerd tho, the previous owner has told me that it was on there before he had it. which means its 10 years old. prob time for a new one. anyone got any ideas on which is the best one to go for.

g60dan. gonna get a vagcom kit as dont know anyone with one, will see wot that says. cheers

 

[s3gazz]

i had same prob but mine was over boosting so tuck it back to garage and they sorted it

 

[jimmer 22]

what was the problem with it mate

 

[SIMPLESIMON]

Hi, I would say definate DV fault. Mines been sticking lately, giving a loss of power

 

[Welly]

Deffo fit a piece of vac hose to the top nipple on the DV and suck through it until the DV is up.

Then hold the vacuum in there for a few seconds, then let go. You should hear the DV snap shut.

 

[murran]

hmmmm wouldnt be the intake pipe sucking in on itself would it?

 

[Welly]

hmmmm wouldnt be the intake pipe sucking in on itself would it?

Wouldn't cause that level of power loss mate. Deffo needs some VAG COM and block 115 logging.

 

[jimmer 22]

cheers for the info guys. have got vag com on the way and will have a good check over the dv and the pipes soon as i get chance. will let you know how i get on. cheers.