S4 / RS4 (B5 Platform) Discussion Discussion forum for the B5 Audi S4 & RS4 produced from 1998-2002

PCV to oil catch can= vacuum leak.

Thread Tools
 
Search this Thread
 
Old 10-29-2008, 12:46 PM
  #1  
Junior Member
Thread Starter
 
MikeD-9000's Avatar
 
Join Date: Feb 2004
Posts: 275
Likes: 0
Received 0 Likes on 0 Posts
Default PCV to oil catch can= vacuum leak.

Literally replaced PCV with open vented oil catch can. Used a very snug fitting rubber cover for intake inlet cover. No leak there. The issue is not understanding the system fully, I guess. At idle, there is a vacuum applied to the open air side of the catch can.

I remember something about the 3 crankcase vents interconnecting and meeting up with another vacuumed set of hoses. I'm guessing my vacuum is there.

Should I reattach the open air side to the intake? I don't want to do that, as it will introduce some vacuum to the crankcase, when boosting.

Solutions?
Old 10-29-2008, 01:02 PM
  #2  
AudiWorld Expert
 
nyet's Avatar
 
Join Date: Dec 2000
Posts: 33,078
Likes: 0
Received 0 Likes on 0 Posts
Default you'll need a checkvalve, the vacuum is coming from right behind your tb...

where the stock spider vents into the intake mani
Old 10-29-2008, 01:05 PM
  #3  
Junior Member
Thread Starter
 
MikeD-9000's Avatar
 
Join Date: Feb 2004
Posts: 275
Likes: 0
Received 0 Likes on 0 Posts
Default Thanks, Ny, Was looking at routing to intake. Didnt even think of

Check valve. My head's killing me today, but I still would likely have missed the opportunity. Thx again.
Old 10-29-2008, 01:12 PM
  #4  
AudiWorld Super User
 
~DonQPremiumTequila~'s Avatar
 
Join Date: Jan 2004
Posts: 6,227
Likes: 0
Received 0 Likes on 0 Posts
Default

as in you replaced you spider hose with 3 lines onnecting to a oil catch can?
Old 10-29-2008, 03:11 PM
  #5  
Junior Member
Thread Starter
 
MikeD-9000's Avatar
 
Join Date: Feb 2004
Posts: 275
Likes: 0
Received 0 Likes on 0 Posts
Default Nope- imagine replacing PCV w/can, can vents to atmosphere

Y-pipe hole is covered. The can is hidden well. It's a very tidy install, but I did not know that there is a vacuum applied somewhere on the engine side of PCV.

Like this:

Y
P _
I - <--Hole covvered
P
E


___
catch can --- hose to PCV from engine

The PCV has one end on Y pipe, other has hose from engine. Covered Y pipe hole, put catch inlet on the engine hose using barb.

The catch will be refitted with a one way valve on the outlet side. This will permit air exiting but not entering.
Old 10-29-2008, 03:58 PM
  #6  
AudiWorld Expert
 
nyet's Avatar
 
Join Date: Dec 2000
Posts: 33,078
Likes: 0
Received 0 Likes on 0 Posts
Default np, let me know if you get a setup you like

i've been thinking of running a catchcan for a long time but never got around to deciding on how to set it up.
Old 10-30-2008, 12:53 AM
  #7  
New Member
 
RS_F-Whore's Avatar
 
Join Date: Jan 2003
Posts: 432
Likes: 0
Received 0 Likes on 0 Posts
Default What made you do it this way? I thought the norm was like this ...

<ul><li><a href="http://www.rs246.com/index.php?name=PNphpBB2&amp;file=viewtopic&amp;t=7 2433&amp;highlight=catch">my catch can install.</a></li></ul>
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
psuaudi
A4 (B6 Platform) Discussion
4
12-07-2006 07:55 AM
JohnStr
A4 (B5 Platform) Discussion
7
01-06-2005 08:04 AM
SprinTTer
TT (Mk1) Discussion
3
11-18-2003 10:10 AM
Steve Balgach
Audi 90 / 80 / Coupe quattro / Cabriolet
3
07-23-2003 02:27 AM
moribundman
12v V6 Discussion
6
04-09-2003 11:28 PM



Quick Reply: PCV to oil catch can= vacuum leak.



All times are GMT -8. The time now is 04:12 PM.