Welcome to the North American Subaru Impreza Owners Club Saturday August 30, 2014
Home Forums WikiNASIOC Products Store Modifications Upgrade Garage
NASIOC
Here you can view your subscribed threads, work with private messages and edit your profile and preferences Home Registration is free! Visit the NASIOC Store NASIOC Rules Search Find other members Frequently Asked Questions Calendar Archive NASIOC Upgrade Garage Logout
Go Back   NASIOC > NASIOC Technical > Service & Maintenance

Welcome to NASIOC - The world's largest online community for Subaru enthusiasts!
Welcome to the NASIOC.com Subaru forum.

You are currently viewing our forum as a guest, which gives you limited access to view most discussions and access our other features. By joining our community, free of charge, you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is free, fast and simple, so please join our community today!

If you have any problems with the registration process or your account login, please contact us.
* Registered users of the site do not see these ads.
Reply
 
Thread Tools Display Modes
Old 02-28-2006, 11:20 AM   #1
jjbean114
Scooby Newbie
 
Member#: 49006
Join Date: Nov 2003
Location: Currently in Georgia
Vehicle:
2004 WRX
Rally Blue

Default I may have a vacuum leak!!! NEED HELP ASAP

Yeah i have a '04 wrx sedan and i believe that i have a vacuum leak around the turbo somewhere. Under full throttle the boost gauge is telling me that the engine is receiving air however, when in idle and when i am let off on the gas, the boost gauge is reading a well into the negative. I know that when you intially let off on the gas that i will have a short period of time when the turbo is spooling in reverse (when the boost gauge reads in the negative) however in idle it shouldn't be doing that. If anyone has any ideas of what may be the cause of this please reply.
* Registered users of the site do not see these ads.
jjbean114 is offline   Reply With Quote
Old 02-28-2006, 11:53 AM   #2
HndaTch627
Scooby Guru
 
Member#: 6551
Join Date: May 2001
Chapter/Region: MWSOC
Location: Carol Stream, IL
Vehicle:
'01 GC8 Dinged STM
'09 Concours 14 ABS Black

Default

ummm, first of all a turbo doesn't spool backwards, secondly an engine will always have high vacuum at idle. before you freak out you should understand how an engine really works.
HndaTch627 is offline   Reply With Quote
Old 02-28-2006, 03:12 PM   #3
jjbean114
Scooby Newbie
 
Member#: 49006
Join Date: Nov 2003
Location: Currently in Georgia
Vehicle:
2004 WRX
Rally Blue

Default

actually before you get on my case about it, a turbo can spool backwards. that is the primary reason for a blow off valve. Because when you press down on the clutch you have a certain amount of air that is beginning to build up, back pressure, the air can surge back into the turbo instead of going into the intake. Thus if the blow off valve in not working properly the turbo can spin backwards. the only reason i posted earlier is because i don't know much about the ej20 turbo engine. this car is not my first turbo. i have had 2 previous dsm turbocharged cars before. So i know the general workings of the turbo. What i was really wondering, has anyone encountered this before in there wrxs.
jjbean114 is offline   Reply With Quote
Old 02-28-2006, 03:20 PM   #4
specialev
Scooby Specialist
 
Member#: 90156
Join Date: Jun 2005
Chapter/Region: NWIC
Location: Auburn, Wa
Vehicle:
1986 Syncro Vanaru
07 SV650

Default

Dude, you are getting negative pressure in the manifold because the throttle butterfly isn't open and the engine sucking against the closed butterfly creates vacum. It is totally normal. You should only ever see positive pressure when you are into boost. The turbo does not spool backwards at this time; at idle it shouldn't be spooling at all.
specialev is offline   Reply With Quote
Old 02-28-2006, 03:41 PM   #5
jjbean114
Scooby Newbie
 
Member#: 49006
Join Date: Nov 2003
Location: Currently in Georgia
Vehicle:
2004 WRX
Rally Blue

Default

hey specialev, i know but this is the thing, while just idling, the boost gauge is supposed to read at zero right? but when i am in idle, the boost gauge is reading in the negative. also when i pop the hood i hear a high pitch whistling sound. but under power the boost gauge is reading a little on the low side but know that there is air being forced into the engine.
jjbean114 is offline   Reply With Quote
Old 02-28-2006, 04:07 PM   #6
gotsol
Scooby Specialist
 
Member#: 17346
Join Date: Apr 2002
Chapter/Region: South East
Location: All Over NC
Vehicle:
08 Cayman S
White

Default

I get 19 inches of vacum at idle. I don't know what the high pitched sound might be though
gotsol is offline   Reply With Quote
Old 02-28-2006, 04:19 PM   #7
specialev
Scooby Specialist
 
Member#: 90156
Join Date: Jun 2005
Chapter/Region: NWIC
Location: Auburn, Wa
Vehicle:
1986 Syncro Vanaru
07 SV650

Default

You should be sitting in vacum at idle, with vacum decreasing as you apply throttle and open up the throttle butterfly. You really shouldn't see zero until you are around ~2000-2500 rpms.

The whistling you hear may be a vacum leak. What kind of intake hoses do you have? If you are using the silicone ones they can make a bit of a whistley sound if the clamp isn't on tight enough. Ask me how I know.
specialev is offline   Reply With Quote
Old 02-28-2006, 05:08 PM   #8
jjbean114
Scooby Newbie
 
Member#: 49006
Join Date: Nov 2003
Location: Currently in Georgia
Vehicle:
2004 WRX
Rally Blue

Default

well specialev, how do you know? no everything on the engine is stock, nothing new. but anyways i yeah you guys are right about the fact that there is vacuum when i idle but there is an alot more vacuum then most. I am pretty sure its from the turbo system. I am thinking that it is probably one of the lines leading to either the blowoff valve but anyone have any ideas which line it is? It might not be a vacuum line at all but there is definately a hissing sound.
jjbean114 is offline   Reply With Quote
Old 02-28-2006, 09:37 PM   #9
specialev
Scooby Specialist
 
Member#: 90156
Join Date: Jun 2005
Chapter/Region: NWIC
Location: Auburn, Wa
Vehicle:
1986 Syncro Vanaru
07 SV650

Default

If you have a vacum leak, your vacum at idle will be lower rather than higher. To hunt for leaks you can use a propane torch, with the flame off but the gas on, to probe the vacum connections while the car is running. A vacum leak will be noted if the car's idle increases as the gas is sucked up by the leak. This will get you in the right area where the leak is located, after that you can use some soapy water or Windex to find the exact hose, alternatively, you can just start manhandling connections and see if the leak or hiss goes away. Maybe the noise you are hearing isn't in fact a leak of vacum?
specialev is offline   Reply With Quote
Old 02-28-2006, 09:52 PM   #10
HndaTch627
Scooby Guru
 
Member#: 6551
Join Date: May 2001
Chapter/Region: MWSOC
Location: Carol Stream, IL
Vehicle:
'01 GC8 Dinged STM
'09 Concours 14 ABS Black

Default

btw: turbos don't spin backwards, if you run w/o a blow off valve the noise you hear is the air rushing back thru the impeller but it does not have enough force to spin a turbo backwards because there is exhaust pressure spinning it the other direction
HndaTch627 is offline   Reply With Quote
Old 03-01-2006, 07:54 AM   #11
DrD
Scooby Guru
 
Member#: 22412
Join Date: Aug 2002
Chapter/Region: SWIC
Location: Albuquerque, NM
Vehicle:
2012 Legacy 2.5GT
Ice Silver Metallic

Default

in order for the turbo to spin backwards, you would need to be pulling air into the engine through the exhaust manifold... not gonna happen

If you were reading 0 pressure at idle, then either you have a bad leak, or the boost gauge is messed up.

OEM spec at idle is almost 18 in Hg of vacuum at the brake booster.
DrD is offline   Reply With Quote
Old 03-01-2006, 10:41 AM   #12
HndaTch627
Scooby Guru
 
Member#: 6551
Join Date: May 2001
Chapter/Region: MWSOC
Location: Carol Stream, IL
Vehicle:
'01 GC8 Dinged STM
'09 Concours 14 ABS Black

Default

Quote:
Originally Posted by DrD
in order for the turbo to spin backwards, you would need to be pulling air into the engine through the exhaust manifold... not gonna happen

If you were reading 0 pressure at idle, then either you have a bad leak, or the boost gauge is messed up.

OEM spec at idle is almost 18 in Hg of vacuum at the brake booster.
or you connected the boost gauge to the intake tract and not to the intake manifold
HndaTch627 is offline   Reply With Quote
Old 03-01-2006, 02:18 PM   #13
jjbean114
Scooby Newbie
 
Member#: 49006
Join Date: Nov 2003
Location: Currently in Georgia
Vehicle:
2004 WRX
Rally Blue

Default

well i am sure it is just a minor leak somewhere, i am not too worried about it. However the boost gauge is blipping now. Not a major jump but in idle it is bouncing between about -18 to -19 or according to my boost gauge -.09 to -.1. Also under full load the turbo isn't getting the full amount of flow that it was getting before. It is reading about 2 to 3 psi lower then before. I am just hoping that it is just a minor leak somewhere instead of a broken turbine or a cracked housing. However the boost gauge is not an aftermarket gauge, it was the one that came from the factory. but anyways i wanted to let you guys know that i appreciate all your feedbacks and ideas.
jjbean114 is offline   Reply With Quote
Old 03-01-2006, 02:31 PM   #14
aaTDwrx
Scooby Newbie
 
Member#: 83340
Join Date: Mar 2005
Location: NJ
Vehicle:
2003 Impreza WRX
Black

Default

If you didn't want to listen to what all these people were telling you then you shouldn't have even posted a question. Not one person thinks that you have a leak but you refuse to listen. Just because the gauge is from the factory doesn't mean it is working properly you should probably use an after marked gauge to check your problem before you make it worse than it really is.
aaTDwrx is offline   Reply With Quote
Old 03-01-2006, 02:55 PM   #15
overdose
Scooby Specialist
 
Member#: 46399
Join Date: Oct 2003
Chapter/Region: MWSOC
Location: Grand Rapids, MI
Vehicle:
0000 Knows nothing,
about nothing.

Default

+12345

you're really dumb and should not post here ever again, also when you sell the car let us know so none of us let anyone buy it.

Member#: 49006

your number is way too low to be this stupid, brain trauma recently?
overdose is offline   Reply With Quote
Old 03-01-2006, 04:13 PM   #16
REVNU
Scooby Specialist
 
Member#: 82147
Join Date: Mar 2005
Chapter/Region: SCIC
Location: Fulas, CA
Vehicle:
2005 WRX Sedan
Aspen White

Default

Quote:
Originally Posted by overdose
+12345

you're really dumb and should not post here ever again, also when you sell the car let us know so none of us let anyone buy it.

Member#: 49006

your number is way too low to be this stupid, brain trauma recently?
HAHAHA

I can't believe how much some people "think" they know. If you owned TWO turbo cars before this, then you would/should have known that you should not be at ZERO when at idle. This is my first turbo car and even I knew that! I think you need to do some serious reading up on your car before you start spouting off claims AND insults to people on a subject you obviously know nothing about.

On a more positive note: NASDAQ is up 33.25 today!

~REVNU
REVNU is offline   Reply With Quote
Old 03-01-2006, 08:53 PM   #17
DrD
Scooby Guru
 
Member#: 22412
Join Date: Aug 2002
Chapter/Region: SWIC
Location: Albuquerque, NM
Vehicle:
2012 Legacy 2.5GT
Ice Silver Metallic

Default

Quote:
Originally Posted by REVNU
If you owned TWO turbo cars before this, then you would/should have known that you should not be at ZERO when at idle.
actually, you could broaden that to any cars - NA cars also run vacuum at idle then approach atmospheric under load.
DrD is offline   Reply With Quote
Old 03-01-2006, 09:03 PM   #18
supermarkus
Scooby Guru
 
Member#: 6971
Join Date: May 2001
Location: Edmonds, Washington, USA
Vehicle:
2008 WRX STi
SSM

Default

http://www.howstuffworks.com

FTW! This thread should have ended at post #2.
supermarkus is offline   Reply With Quote
Old 03-02-2006, 01:49 AM   #19
HndaTch627
Scooby Guru
 
Member#: 6551
Join Date: May 2001
Chapter/Region: MWSOC
Location: Carol Stream, IL
Vehicle:
'01 GC8 Dinged STM
'09 Concours 14 ABS Black

Default

Quote:
Originally Posted by supermarkus
http://www.howstuffworks.com

FTW! This thread should have ended at post #2.
unforunately it continued into a flame bait fest...then again i have no idea how engines work
HndaTch627 is offline   Reply With Quote
Old 03-02-2006, 03:26 AM   #20
Uncle Scotty
Scooby Guru
 
Member#: 16200
Join Date: Mar 2002
Vehicle:
OK Houston
we have an Uncle

Default

....and the high pitch whistle is likely electrical in nature
Uncle Scotty is offline   Reply With Quote
Old 03-02-2006, 06:25 PM   #21
specialev
Scooby Specialist
 
Member#: 90156
Join Date: Jun 2005
Chapter/Region: NWIC
Location: Auburn, Wa
Vehicle:
1986 Syncro Vanaru
07 SV650

Default

Quote:
Originally Posted by Uncle Scotty
....and the high pitch whistle is likely electrical in nature
What would that be, then?
specialev is offline   Reply With Quote
Old 03-03-2006, 02:17 AM   #22
HndaTch627
Scooby Guru
 
Member#: 6551
Join Date: May 2001
Chapter/Region: MWSOC
Location: Carol Stream, IL
Vehicle:
'01 GC8 Dinged STM
'09 Concours 14 ABS Black

Default

alternator...they because of their position on the motor the sound from them can travel very easily

that or an up-pipe gasket
HndaTch627 is offline   Reply With Quote
Old 03-04-2006, 09:54 PM   #23
ase05scooby
Scooby Newbie
 
Member#: 103710
Join Date: Dec 2005
Chapter/Region: South East
Location: canton
Vehicle:
05 impreza wrx
red

Default

Having negative reading at idle is normal it shouldnt be sitting at zero at idle or you do have a vaccum leak. Your engine should have 18 to 19 hg of vaccum at idle and decrease as your rpms increase.
ase05scooby is offline   Reply With Quote
Old 03-05-2006, 10:49 AM   #24
supermarkus
Scooby Guru
 
Member#: 6971
Join Date: May 2001
Location: Edmonds, Washington, USA
Vehicle:
2008 WRX STi
SSM

Default

Quote:
Originally Posted by HndaTch627
alternator...they because of their position on the motor the sound from them can travel very easily

that or an up-pipe gasket

In an STi or maybe even a new WRX the whine could also be the electronic throttle. Just FYI.
supermarkus is offline   Reply With Quote
Old 03-08-2006, 03:09 PM   #25
HndaTch627
Scooby Guru
 
Member#: 6551
Join Date: May 2001
Chapter/Region: MWSOC
Location: Carol Stream, IL
Vehicle:
'01 GC8 Dinged STM
'09 Concours 14 ABS Black

Default

Quote:
Originally Posted by supermarkus
In an STi or maybe even a new WRX the whine could also be the electronic throttle. Just FYI.
something i never expected to whine, the Eletronice Throttle bodies on honda's are silent
HndaTch627 is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Leaking Oil! I Need Help ASAP steve2k1116 Factory 2.5L Turbo Powertrain 9 04-28-2009 07:38 PM
Leak from turbo oil line. Need help ASAP nqwan Factory 2.0L Turbo Powertrain 3 03-31-2008 04:27 PM
do I have a vacuum leak? (different, I swear!) NETWRX Factory 2.0L Turbo Powertrain 15 10-19-2007 11:23 PM
Think I may have an exhaust leak.. flyingmachine Normally Aspirated Powertrain 2 06-06-2005 01:51 PM
Need help ASAP! Found oi leak at bottom of stainless steel oil line on my sr50 odin1 Factory 2.5L Turbo Powertrain 12 10-18-2004 11:37 AM


All times are GMT -4. The time now is 01:18 AM.


Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Powered by Searchlight © 2014 Axivo Inc.
Copyright ©1999 - 2014, North American Subaru Impreza Owners Club, Inc.