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 > Factory 2.5L Turbo Powertrain

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 02-04-2014, 11:53 AM   #1
TyranosaurusWRX
Scooby Specialist
 
Member#: 25731
Join Date: Oct 2002
Chapter/Region: MWSOC
Location: Ft Wayne, IN
Vehicle:
02 wrx(sold)/2005
Sti/ 93 Leg Wag

Default Low oil pressure

Been trying to troubleshoot a low oil pressure situation. I have a simple Autometer gauge with an electronic sender. The sender is connected to a braided line going to the block. Normally when all is working the gauge reads between 75-80psi when the block is cold and once it warms up it idles between 15-20 psi and revs up to 70 psi while driving. When I first start the car up cold I'm getting almost 75psi but once it warms up fully I get about 12psi on idle and am lucky to hit 45psi when revving it up driving. It's a recent motor build so I really haven't ran this hard at all. It only has a little over 700 break in miles boosting to about 5lb on the average keeping the revs under 4k so I really didn't notice the problem right away.

I've replaced the sender and the oil pump, and even changed the oil just in case there was an issue with viscosity. The old oil really wasn't in bad shape, not a lot of metal or flakes outside of normal break in. I would think that if the oil pickup was cracked it would not be getting any pressure, or relatively none. Not sure really what else could cause it....maybe one of the two grommets/seals in the oil pan?
* Registered users of the site do not see these ads.
TyranosaurusWRX is offline   Reply With Quote
Old 02-04-2014, 12:20 PM   #2
atomicfire
Scooby Specialist
 
Member#: 136296
Join Date: Dec 2006
Chapter/Region: TXIC
Location: Midtown, Houston, TX
Vehicle:
2005 STi
OBP

Default

What kind of oil, and where was the oil pressure sender installed? What are the specs on the block build? DAVCS? Oil pump? What internals were used, and what was the rod and mains clearance?
atomicfire is online now   Reply With Quote
Old 02-04-2014, 12:57 PM   #3
LIChuck
Scooby Specialist
 
Member#: 266122
Join Date: Dec 2010
Chapter/Region: Tri-State
Location: Patchogue, NY
Vehicle:
2007 WRX Limited
UGM

Default

The gauge could be bad, it sounds like all your readings are low. You need to either get the gauge and sender calibrated as a system or mount a temporary high quality gauge to check the pressure.
LIChuck is offline   Reply With Quote
Old 02-04-2014, 01:40 PM   #4
TyranosaurusWRX
Scooby Specialist
 
Member#: 25731
Join Date: Oct 2002
Chapter/Region: MWSOC
Location: Ft Wayne, IN
Vehicle:
02 wrx(sold)/2005
Sti/ 93 Leg Wag

Default

Quote:
Originally Posted by atomicfire View Post
What kind of oil, and where was the oil pressure sender installed? What are the specs on the block build? DAVCS? Oil pump? What internals were used, and what was the rod and mains clearance?
Without getting too far off topic (I understand why you are asking tho) the specs/clearances are well within reason. The first oil pump was the oem 10mm. Also changed it out to a 12mm (because it was available) with absolutely no change in pressure. The short block (built 2.35 stroker) was previously used (and working) in another car before I sold it with a stock long block and kept this short block - and did not have these issues at that time. This is my 05 Sti btw, intake AVCS only.

Quote:
Originally Posted by LIChuck View Post
The gauge could be bad, it sounds like all your readings are low. You need to either get the gauge and sender calibrated as a system or mount a temporary high quality gauge to check the pressure.
LIChuck, I agree and that thought crossed my mind but why would it hit close to proper pressure at start up? Seems like it would either work or not but I've seen stranger things.
TyranosaurusWRX is offline   Reply With Quote
Old 02-04-2014, 01:45 PM   #5
atomicfire
Scooby Specialist
 
Member#: 136296
Join Date: Dec 2006
Chapter/Region: TXIC
Location: Midtown, Houston, TX
Vehicle:
2005 STi
OBP

Default

Where was the oil pressure sender installed? You'll see different readings in different areas.
atomicfire is online now   Reply With Quote
Old 02-04-2014, 01:46 PM   #6
TyranosaurusWRX
Scooby Specialist
 
Member#: 25731
Join Date: Oct 2002
Chapter/Region: MWSOC
Location: Ft Wayne, IN
Vehicle:
02 wrx(sold)/2005
Sti/ 93 Leg Wag

Default

Quote:
Originally Posted by atomicfire View Post
Where was the oil pressure sender installed? You'll see different readings in different areas.
Oh yeah, meant to mention that. It's on the back of the block in the port over the #3 piston. Pretty much had it in that locaton in many many builds.
TyranosaurusWRX is offline   Reply With Quote
Old 02-04-2014, 05:51 PM   #7
mmetalmilitiaa
Scooby Specialist
 
Member#: 160878
Join Date: Oct 2007
Chapter/Region: MAIC
Location: Fairfax, VA
Vehicle:
06 sti
sgm

Default

Couldn't a hairline crack in the pickup cause lower pressures, yet not cause zero pressure?

When mine started forming a crack, my stock light would flicker for a second every time I would start the car, but I didn't have a oil pressure gauge at the time to see what it was reading at higher rpm's. But I can imagine that it was lower than normal :P

I'm just kinda thinking out loud..
mmetalmilitiaa is offline   Reply With Quote
Old 02-04-2014, 07:15 PM   #8
TyranosaurusWRX
Scooby Specialist
 
Member#: 25731
Join Date: Oct 2002
Chapter/Region: MWSOC
Location: Ft Wayne, IN
Vehicle:
02 wrx(sold)/2005
Sti/ 93 Leg Wag

Default

It very well could be. I guess any way you slice it I'm going to have to pull the oil pan. I was just under the impression that when the pick up tubes cracked they opened up...but I could see a hairline causing problems like that.
TyranosaurusWRX is offline   Reply With Quote
Old 02-04-2014, 08:38 PM   #9
KillerBMotorsport
NASIOC Vendor
 
Member#: 198281
Join Date: Dec 2008
Chapter/Region: MAIC
Location: Virginia
Vehicle:
2005 WRX/STi
WRB of course

Default

If the pickup has a crack you might have funky symptoms for an hour or a few days, or maybe more, if you're lucky enough to have any symptoms.

Definitely a good idea to pull the pan. Might not be a bad idea to get a cheap $15 mechanical gauge and verify the pressure you're seeing too. They are handy to keep in your toolbox too. Personally, I wouldn't continue to drive the car until finding out what's going on, that pressure is below the factory minimum spec, 14psi, which is horribly low.
KillerBMotorsport is offline   Reply With Quote
Old 02-04-2014, 09:23 PM   #10
sultanofsubguns
Scooby Newbie
 
Member#: 351404
Join Date: Mar 2013
Chapter/Region: NWIC
Location: somewhere over the rainbow
Vehicle:
02 WRX Wagon
ProbablySomethingMundane

Default

Check the pickup I just lost a motor in my WRX from the pickup tube failing at 58k.
sultanofsubguns is offline   Reply With Quote
Old 02-04-2014, 09:44 PM   #11
TyranosaurusWRX
Scooby Specialist
 
Member#: 25731
Join Date: Oct 2002
Chapter/Region: MWSOC
Location: Ft Wayne, IN
Vehicle:
02 wrx(sold)/2005
Sti/ 93 Leg Wag

Default

Thanks for all the input. The car is definitely not moving until I'm confident of the issue.
TyranosaurusWRX is offline   Reply With Quote
Old 02-10-2014, 10:51 AM   #12
mmetalmilitiaa
Scooby Specialist
 
Member#: 160878
Join Date: Oct 2007
Chapter/Region: MAIC
Location: Fairfax, VA
Vehicle:
06 sti
sgm

Default

Any updates?
mmetalmilitiaa is offline   Reply With Quote
Old 02-10-2014, 12:02 PM   #13
TyranosaurusWRX
Scooby Specialist
 
Member#: 25731
Join Date: Oct 2002
Chapter/Region: MWSOC
Location: Ft Wayne, IN
Vehicle:
02 wrx(sold)/2005
Sti/ 93 Leg Wag

Default

Not yet, it's been way too snowy and cold I used to be that ambitious but not so much anymore lol. I will definitely report back.

Last edited by TyranosaurusWRX; 02-19-2014 at 11:24 PM.
TyranosaurusWRX is offline   Reply With Quote
Old 02-19-2014, 11:22 PM   #14
TyranosaurusWRX
Scooby Specialist
 
Member#: 25731
Join Date: Oct 2002
Chapter/Region: MWSOC
Location: Ft Wayne, IN
Vehicle:
02 wrx(sold)/2005
Sti/ 93 Leg Wag

Default

I hooked up a different gauge to the oil pressure feed line and got the same results. Pulled the pan today and took a bright light and some fine sandpaper to the oil pickup tube and I don't believe I see any cracks. The o-ring that goes to the back corner of the pan to the block is looking a little gnarled so I'm thinking that this might be the issue.



TyranosaurusWRX is offline   Reply With Quote
Old 02-20-2014, 05:59 AM   #15
KillerBMotorsport
NASIOC Vendor
 
Member#: 198281
Join Date: Dec 2008
Chapter/Region: MAIC
Location: Virginia
Vehicle:
2005 WRX/STi
WRB of course

Default

That's not your issue. That's just a vent line. The seal goes way back to N/A applications and has just stuck around. We have no seal on our pan there, in fact other aftermarket pans have NOTHING there. It's purpose is to reduce the effects of crankshaft turbulence on the PCV vent.

That looks about normal for them, they are not an o-ring. Did you pull the pickup out?

You can have a very small crack that is difficult to detect. Sometimes impossible to see until you take it our and flex it some. Examples...






KillerBMotorsport is offline   Reply With Quote
Old 02-20-2014, 07:21 AM   #16
TyranosaurusWRX
Scooby Specialist
 
Member#: 25731
Join Date: Oct 2002
Chapter/Region: MWSOC
Location: Ft Wayne, IN
Vehicle:
02 wrx(sold)/2005
Sti/ 93 Leg Wag

Default

Thanks for the clarification, I was never really sure of it's function. I know that it's never been an issue before. I'll warm up the tube and put some pressure on it at different angles and see if something shows but at this point it's not obvious.
TyranosaurusWRX is offline   Reply With Quote
Old 02-20-2014, 09:48 AM   #17
KillerBMotorsport
NASIOC Vendor
 
Member#: 198281
Join Date: Dec 2008
Chapter/Region: MAIC
Location: Virginia
Vehicle:
2005 WRX/STi
WRB of course

Default

No problem. If you've got the pan off and pickup out. You might as well just replace it, If an aftermarket piece is not in the budget, replace it with a new one every 20K miles to insure you don't have this kind of failure.

Here are some pics of what to look for in the braze flux, tell tale signs of stress...





The last thing you want is this to happen...

KillerBMotorsport is offline   Reply With Quote
Old 02-20-2014, 10:13 AM   #18
TyranosaurusWRX
Scooby Specialist
 
Member#: 25731
Join Date: Oct 2002
Chapter/Region: MWSOC
Location: Ft Wayne, IN
Vehicle:
02 wrx(sold)/2005
Sti/ 93 Leg Wag

Default

The 2nd pic with the blue circle...that's a crack, not the flux?
TyranosaurusWRX is offline   Reply With Quote
Old 02-20-2014, 10:38 AM   #19
KillerBMotorsport
NASIOC Vendor
 
Member#: 198281
Join Date: Dec 2008
Chapter/Region: MAIC
Location: Virginia
Vehicle:
2005 WRX/STi
WRB of course

Default

Stress in the flux/tube can cause the appearance of crazing (top pic) or flaking (bottom pic) typically in a line. Usually, but not always, it's seen at or near the tube's weld seam. You can see this well in the bottom pic where the weld seam runs up the tube, right under the area circled. Neither of these examples are a crack... yet.
KillerBMotorsport is offline   Reply With Quote
Old 03-04-2014, 11:09 AM   #20
TyranosaurusWRX
Scooby Specialist
 
Member#: 25731
Join Date: Oct 2002
Chapter/Region: MWSOC
Location: Ft Wayne, IN
Vehicle:
02 wrx(sold)/2005
Sti/ 93 Leg Wag

Default

Just an update.... replaced the oil pick up (yes, with the Killer B ;]), pulled and cleaned out the oil cooler just in case, replaced filter and oil. I'm only getting about 5-10psi more out of it. I'm thinking that's more the 15w-40 rotella than anything. Maybe it's in the build but I'm not seeing where. I fount my notes regarding the ACL main bearing clearances and they were all right around .0015 via plastigauge....So not sure what else to look for but the search goes on.
TyranosaurusWRX is offline   Reply With Quote
Old 03-04-2014, 11:35 AM   #21
Razgeiz
NASIOC Supporter
 
Member#: 358782
Join Date: Jun 2013
Chapter/Region: MWSOC
Location: Springfield, Illinois
Vehicle:
2013 STi
DGM

Default

Quote:
Originally Posted by TyranosaurusWRX View Post
Just an update.... replaced the oil pick up (yes, with the Killer B ;]), pulled and cleaned out the oil cooler just in case, replaced filter and oil. I'm only getting about 5-10psi more out of it. I'm thinking that's more the 15w-40 rotella than anything. Maybe it's in the build but I'm not seeing where. I fount my notes regarding the ACL main bearing clearances and they were all right around .0015 via plastigauge....So not sure what else to look for but the search goes on.
Sad face for the plastigauge your clearances are probably off from what that sheet says.
Razgeiz is online now   Reply With Quote
Old 03-04-2014, 11:39 AM   #22
Asharus
Scooby Specialist
 
Member#: 276300
Join Date: Mar 2011
Vehicle:
2011 WRX Ltd 5DR SWP
349awhp/366tq @19psi E85

Default

did you keep the old pickup tube? did you find any cracks?
Asharus is offline   Reply With Quote
Old 03-04-2014, 12:11 PM   #23
TyranosaurusWRX
Scooby Specialist
 
Member#: 25731
Join Date: Oct 2002
Chapter/Region: MWSOC
Location: Ft Wayne, IN
Vehicle:
02 wrx(sold)/2005
Sti/ 93 Leg Wag

Default

Quote:
Originally Posted by Razgeiz View Post
Sad face for the plastigauge your clearances are probably off from what that sheet says.
I know some people like to make that argument but plastigauge has always worked for me in the past. Not to mention even the manual states to use it. .0015 is a little loose for factory tolerances but it's not that uncommon I don't think for the ACLs depending on which ones you use.

Quote:
Originally Posted by Asharus View Post
did you keep the old pickup tube? did you find any cracks?
No cracks, yeah I kept the old one. It looks a lot like the middle pic on post 17.
TyranosaurusWRX is offline   Reply With Quote
Old 03-04-2014, 01:43 PM   #24
KillerBMotorsport
NASIOC Vendor
 
Member#: 198281
Join Date: Dec 2008
Chapter/Region: MAIC
Location: Virginia
Vehicle:
2005 WRX/STi
WRB of course

Default

5-10psi everywhere or just at idle?

So to review... You have a new pickup. Have tried different pumps.

What is you idle RPM? What port are you measuring oil pressure from?
KillerBMotorsport is offline   Reply With Quote
Old 03-04-2014, 01:52 PM   #25
TyranosaurusWRX
Scooby Specialist
 
Member#: 25731
Join Date: Oct 2002
Chapter/Region: MWSOC
Location: Ft Wayne, IN
Vehicle:
02 wrx(sold)/2005
Sti/ 93 Leg Wag

Default

Actually everywhere but idle to be honest. Idle RPM is about 850-900. Pressure is measured from the galley above the #3 piston, near the breather outlet.
TyranosaurusWRX 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


All times are GMT -4. The time now is 08:19 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.