Welcome to the North American Subaru Impreza Owners Club Thursday July 31, 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 10-22-2012, 12:06 PM   #1
thebigevilfoot
Scooby Specialist
 
Member#: 253836
Join Date: Aug 2010
Location: Central NJ
Vehicle:
2011 WRX-DGM
20g STImikey tune RIP CSK

Default 2011 WRX - Rough idle, constant stalling, won't stay running

Hey everyone, I was hoping someone could point me in the right direction of where to begin diagnosing this problem.

Heres the story:
I was coming off the highway after doing a pretty big pull, the car ran through the pull better than ever, it felt great all through the rpm range, as I was coming off the exit, I clutched in, my rev's dropped, and suddenly they dropped too far and the car began stalling out, I rolled into a parking lot and began looking for a vac leak somewhere, assuming a FMIC pipe came loose. I couldn't find anything, no smoke from the motor or oil filler, oil levels are fine, oil looks great/fresh. I started her up again to see if it would run. It began idling super rough bouncing around 400-500 rpm's almost cutting out, I revved it up to keep it running (at which point a little whitish/grayish smoke came out of the exhaust, but nothing serious so I assume) The car seemed to smooth out and the revs came up to 900 and it was idling fine. I drove it slowly home, it ran fine, obviously I didn't get on it, but from 0-3000 rpm's it drove like normal. I came to a light, at which point I clutched in again, the revs dropped and it started to barely run, until it finally stalled out again, I waited a bit a gain, started it up, revved it to keep it from dying and got it home, now it's home and I just don't know where to start. The MAF is plugged in, the AP read -10 a idle on the boost, so it doesn't seem to have any leaks, no codes were thrown, the engine doesn't sound weird when the idle smooths out, but the when it's rough, the car shakes pretty violently, and I hear a horrible vibration/shaking in the fuel tank behind me. On a side note, the past few months it seems like my Walbro is pretty damn loud, and when I'm at a stop I can hear it's drone, and if I rev it, it makes like a high pitched whine (but it does still prime when I turn it to the on position). On another side note, for as long as I can seem to remember, when I come to a stop in the car by clutching in, the revs always seemed to drop a little to 500, the car shakes a very little bit and the revs come up, but I heard that's pretty common? Is my fuel pump failing? Maybe it's just me, but on my last fill up (the current fill up that is) my car went through the first half a tank really fast, granted I have 750cc injectors, but it still seemed to go pretty fast. No drops of anything on the ground as far as I can see. Before this suddenly happened, the car was running AWESOME, I mean no hesitation or stuttering just raw power when I wanted it and normal when I didn't. Plugs on it are pretty new, the car only has 30k miles and I changed them maybe 15k ago to one step colder. I'm also 99% sure the last fill up was 93 as always (I go to the same gas station every fill up and they know me). Any clues? Thanks

Tom

Sorry bout the length of this, I just am a little scared, because anytime something like this did ever happen, it was a vac leak at the front mount somewhere, and this time the vac pressure checks out.
* Registered users of the site do not see these ads.
thebigevilfoot is offline   Reply With Quote
Old 10-22-2012, 12:18 PM   #2
xluben
Scooby Guru
 
Member#: 261612
Join Date: Oct 2010
Location: Minneapolis, MN
Vehicle:
2012 Forester 2.5X
2002 WRX Sedan

Default

Sounds like a bosot leak to me. Have you secured the hose going from the top of the BPV to the back of the manifold? That one pops off pretty easily. Put it back on and use a zip tie. Also remove the rubber "caps" on both ends of the throttle body hose if you haven't done that already.
xluben is offline   Reply With Quote
Old 10-22-2012, 12:18 PM   #3
Tripintaz
Scooby Specialist
 
Member#: 245218
Join Date: Apr 2010
Chapter/Region: South East
Location: FL
Vehicle:
2013 STI Limited

Default

#1 Check MUCH MORE thoroughly for boost leaks
#2 Check the AP to see if your fuel trims are trending beyond normal
#3 Check your fuel pump to make sure it is still operating correctly and that it is seated properly in the canister. Did you install it or did a shop? How did you address the part where people usually double up on the O-rings? (exactly why I'll never buy a warlboro for my car. The DW65c is a direct fit replacement)

Do the logs show anything weird?
Tripintaz is offline   Reply With Quote
Old 10-22-2012, 12:20 PM   #4
Tripintaz
Scooby Specialist
 
Member#: 245218
Join Date: Apr 2010
Chapter/Region: South East
Location: FL
Vehicle:
2013 STI Limited

Default

Quote:
Originally Posted by xluben View Post
Sounds like a bosot leak to me. Have you secured the hose going from the top of the BPV to the back of the manifold? That one pops off pretty easily. Put it back on and use a zip tie. Also remove the rubber "caps" on both ends of the throttle body hose if you haven't done that already.

I just had to replace this hose yesterday. Mine blew open at one of the bends and then my vacuum lines started all popping off. A new BPV pipe and a bag of zip ties and its all good now.
Tripintaz is offline   Reply With Quote
Old 10-22-2012, 12:21 PM   #5
dsmtweaker
Scooby Specialist
 
Member#: 265405
Join Date: Nov 2010
Chapter/Region: MWSOC
Location: Traverse City Michigan
Vehicle:
2013 Audi
Black

Default

What all mods do you have done?
dsmtweaker is offline   Reply With Quote
Old 10-22-2012, 12:53 PM   #6
thebigevilfoot
Scooby Specialist
 
Member#: 253836
Join Date: Aug 2010
Location: Central NJ
Vehicle:
2011 WRX-DGM
20g STImikey tune RIP CSK

Default

Update, went downstairs to start it again. Started fine, gave it a rev, it shut right off as ifu turned the key. I put 2 rings on the pump, the bpv hose is On at the bpv. All work has been done myself. It fully bolted on minus turbo. Headerback fmic ebcs bpv etc.
thebigevilfoot is offline   Reply With Quote
Old 10-22-2012, 01:00 PM   #7
Jose99
Scooby Specialist
 
Member#: 164319
Join Date: Nov 2007
Chapter/Region: Tri-State
Location: Lakehurst NAS, NJ
Vehicle:
2013 STi/05 Rs
Silver Bullet

Default

Quote:
Originally Posted by thebigevilfoot View Post
Update, went downstairs to start it again. Started fine, gave it a rev, it shut right off as ifu turned the key. I put 2 rings on the pump, the bpv hose is On at the bpv. All work has been done myself. It fully bolted on minus turbo. Headerback fmic ebcs bpv etc.
Excuse my stupid question but why would you put two O-rings on the fuel pump instead of the one and the spacer thing that comes with it?
Jose99 is offline   Reply With Quote
Old 10-22-2012, 01:38 PM   #8
thebigevilfoot
Scooby Specialist
 
Member#: 253836
Join Date: Aug 2010
Location: Central NJ
Vehicle:
2011 WRX-DGM
20g STImikey tune RIP CSK

Default

There is enough room for 2 rings and the spacer, 1 doesn't give a good seal, I dot mine is just si damn loud, at idle I can hear it over my frggen' magnaflow haha.
thebigevilfoot is offline   Reply With Quote
Old 10-22-2012, 01:55 PM   #9
xluben
Scooby Guru
 
Member#: 261612
Join Date: Oct 2010
Location: Minneapolis, MN
Vehicle:
2012 Forester 2.5X
2002 WRX Sedan

Default

Quote:
Originally Posted by thebigevilfoot View Post
the bpv hose is On at the bpv.
Check the other side of that hose.
xluben is offline   Reply With Quote
Old 10-22-2012, 01:57 PM   #10
thebigevilfoot
Scooby Specialist
 
Member#: 253836
Join Date: Aug 2010
Location: Central NJ
Vehicle:
2011 WRX-DGM
20g STImikey tune RIP CSK

Default

Will do. Thanks for the advice... Fingers crossed
thebigevilfoot is offline   Reply With Quote
Old 10-22-2012, 02:11 PM   #11
Tripintaz
Scooby Specialist
 
Member#: 245218
Join Date: Apr 2010
Chapter/Region: South East
Location: FL
Vehicle:
2013 STI Limited

Default

Quote:
Originally Posted by xluben View Post
Check the other side of that hose.
I had a hard time pulling mine off when I was replacing it yesterday. If that side blew off then holy ****.

Quote:
Originally Posted by thebigevilfoot View Post
Will do. Thanks for the advice... Fingers crossed
Check the hose for any breaks too. Also, underneath the intake manifold where the BPV hose attaches to the turbo inlet is quite a few vacuum lines to check. IRRC there are 3 or 4 that attach to the turbo inlet itself. One is for the BPV, one for the PVC system, and one attaches to the boost sensor and if you have a 3 port EBCS probably that too. Towards the back of the intake where the BPV hose runs, there are 3 vacuum lines underneath it. 2 of them have little c clamps attached and one does not. You will want to check these too.
Tripintaz is offline   Reply With Quote
Old 10-22-2012, 03:32 PM   #12
xluben
Scooby Guru
 
Member#: 261612
Join Date: Oct 2010
Location: Minneapolis, MN
Vehicle:
2012 Forester 2.5X
2002 WRX Sedan

Default

Quote:
Originally Posted by Tripintaz View Post
I had a hard time pulling mine off when I was replacing it yesterday. If that side blew off then holy ****.
That is the most common issue, besides the rubber caps on the throttle body hose. It is a straight, smooth, plastic nipple. No barb or clamp or anything to hold the hose on.
xluben is offline   Reply With Quote
Old 10-22-2012, 04:21 PM   #13
Tripintaz
Scooby Specialist
 
Member#: 245218
Join Date: Apr 2010
Chapter/Region: South East
Location: FL
Vehicle:
2013 STI Limited

Default

Quote:
Originally Posted by xluben View Post
That is the most common issue, besides the rubber caps on the throttle body hose. It is a straight, smooth, plastic nipple. No barb or clamp or anything to hold the hose on.

I learn something new everyday. There are so many easier places for lines to pop off since that one has a clamp on it. My BPV pipe actually exploded out of the side rather than come lose from the turbo inlet or the BPV itself. But hey, I've seen crazier things happen to cars.
Tripintaz is offline   Reply With Quote
Old 10-22-2012, 05:35 PM   #14
thebigevilfoot
Scooby Specialist
 
Member#: 253836
Join Date: Aug 2010
Location: Central NJ
Vehicle:
2011 WRX-DGM
20g STImikey tune RIP CSK

Default

Guys, I'm sorry, but I'm a dumbass. I rechecked all the piping to the FMIC, a quick tug and the passenger side pipe nearest to the core fell right out, retightened and it's good.

On a side note, I noticed that my targest boost at idle is -10.8 and mine only shows in at -10. Is this a big deal? Also I have a FMIC but am not tuned for it yet (I understand gains are not there, but I'm waiting for my universal IWG bracket to come in for my 20g retune) but since it's bigger can that explain why I'm at -10 instead of -11ish? Or do I just have a small leak somewhere? Thanks

Tom
thebigevilfoot is offline   Reply With Quote
Old 10-22-2012, 05:38 PM   #15
Wicked Innovation
NASIOC Vendor
 
Member#: 265606
Join Date: Nov 2010
Location: Manchester, NH
Default

your target boost at idle that you are logging is simply whatever is in the boost control table. comparing it to your manifold pressure doesnt tell you anything as at anything less than wastegate boost pressure, that table wont have any effect.
Wicked Innovation is offline   Reply With Quote
Old 10-23-2012, 08:56 AM   #16
Tripintaz
Scooby Specialist
 
Member#: 245218
Join Date: Apr 2010
Chapter/Region: South East
Location: FL
Vehicle:
2013 STI Limited

Default

Quote:
Originally Posted by thebigevilfoot View Post
Guys, I'm sorry, but I'm a dumbass. I rechecked all the piping to the FMIC, a quick tug and the passenger side pipe nearest to the core fell right out, retightened and it's good.

On a side note, I noticed that my targest boost at idle is -10.8 and mine only shows in at -10. Is this a big deal? Also I have a FMIC but am not tuned for it yet (I understand gains are not there, but I'm waiting for my universal IWG bracket to come in for my 20g retune) but since it's bigger can that explain why I'm at -10 instead of -11ish? Or do I just have a small leak somewhere? Thanks

Tom
It's called Target Boost because the ECU will try and reach that value. It's not always possible to hit the exact number the ECU is targeting. Hence TARGET.

I'm shaking my head that you didn't check the intercooler piping thoroughly first...
Tripintaz is offline   Reply With Quote
Old 10-23-2012, 10:58 AM   #17
some dude
Scooby Specialist
 
Member#: 100300
Join Date: Nov 2005
Chapter/Region: MWSOC
Location: MIC|-|IG/\N
Vehicle:
06 WRX
CGM

Default

Can u guys tell me why a boost leak would cause this type of behavior?
some dude is offline   Reply With Quote
Old 10-23-2012, 11:01 AM   #18
easterbran
Scooby Specialist
 
Member#: 307359
Join Date: Jan 2012
Chapter/Region: South East
Location: Tyrone,GA
Vehicle:
'05 STi Stage II
OBP

Default

My Sti showed the same problems and it turned out to be the A/F ratio sensor. Try unplugging yours and see if this fixes the rough idle? Just a thought.
easterbran is offline   Reply With Quote
Old 10-23-2012, 12:12 PM   #19
Mitchell.Hackney
Scooby Newbie
 
Member#: 236195
Join Date: Jan 2010
Chapter/Region: RMIC
Location: Orlando, FL
Vehicle:
2012 Impreza WRX STi
SWP

Default

Man, this sounded very similar to mine, which turned out to be the fuel pressure regulator. I'd suggest keeping an eye on your Fuel Pressure since you've installed a larger fuel pump. I have a 2012 STi which is stock other than a DW65c Fuel pump and ID1000cc Injectors with an E85 Tune. My Fuel Pressure regulator went after 12000 Miles. (Maybe 1K with the new setup on a VERY conservative/daily driving tune)
Mitchell.Hackney 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 06:36 PM.


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.