Boost comes and goes - Subaru WRX Forum
 
LinkBack Thread Tools Display Modes
post #1 of 15 Old 09-12-2010, 11:17 PM Thread Starter
WRXtuners Member
 
Join Date: Apr 2010
Location: Colorado
Posts: 7
Skillet is an unknown
Boost comes and goes

2002 wagon, bone stock. 125K. Recent maint: fuel pump/filter, air filter - clean MAF, timing belt, PCV. When boost is working it works perfectly. Sometimes is fades to nothing when driving, sometimes it starts that way. Most times I can turn the car off, restart and boost will be there. I've checked: isolate wastegate - begins to open at 9 psi, full open by 15 psi, smooth operation. Vacuum lines OK. Intake hoses/connections OK. Clean and check stock boost controller - couldn't get to fail. If I unplug vac line to BC to bleed pressure, I never lose boost. Seems like the ECU is closing the boost controller - it doesn't act like a loose wire, and I haven't found anything mechanical. I've reset the ECU, no CEL's. Any ideas on what else I can check? Thanks.
Skillet is offline  
Sponsored Links
Advertisement
 
post #2 of 15 Old 09-12-2010, 11:37 PM
WRXtuners Member
 
basco's Avatar
 
Join Date: Aug 2004
Location: South Carolina
Posts: 1,873
basco is a WRX expert worth listening to basco is a WRX expert worth listening to basco is a WRX expert worth listening to basco is a WRX expert worth listening to basco is a WRX expert worth listening to basco is a WRX expert worth listening to
Send a message via AIM to basco Send a message via MSN to basco
have you tried switching out Boost Controller Solenoids...to me that's what it sounds like is the BCS is failing...try swapping with a friend

FP GT35R MoTeC M800 AndrewTech PPG'd Wagon - 513AWHP
06 Mazdaspeed6 280/330
- Matt
basco is offline  
post #3 of 15 Old 09-12-2010, 11:58 PM Thread Starter
WRXtuners Member
 
Join Date: Apr 2010
Location: Colorado
Posts: 7
Skillet is an unknown
I agree, I was hoping it was gunked & sticking shut. Had it on the bench & cycled it a hundred or so times, it worked perfectly so I moved on. I'd have to buy one, maybe I should test it some more.
Skillet is offline  
post #4 of 15 Old 09-14-2010, 04:38 PM
WRXtuners Member
 
anxiouz's Avatar
 
Join Date: Sep 2010
Location: California
Posts: 61
anxiouz is an unknown
When you say boost "sometimes fades to nothing"...does it hit normal boost and then just taper down really quick?
Does it build boost normal or slower?
Does it hit wastegate boost pressure at least?

I dunno what wastegate boost is on a wrx but on my evo it's around 10-11psi give-or-take. When I had a wastegate solenoid go bad I would only boost to 11psi (usually more slowly than normal) and it would never go above that. A bad solenoid will just leave the wastegate open as a safety precaution if it thinks there's a problem. Kinda sounds like what you're experiencing.

But since you tested that out a bunch of times...my guess is it's electrical. It took me forever to find a slightly freyed (ECU-to-solenoid) wire once. I had to trace the whole thing but as soon as I taped up the kinked wire to maintain the proper connection, it fixed my problem. It stumped a dealer for several days on repeated trips so it was extremely difficult to locate though.
anxiouz is offline  
post #5 of 15 Old 09-16-2010, 10:35 PM Thread Starter
WRXtuners Member
 
Join Date: Apr 2010
Location: Colorado
Posts: 7
Skillet is an unknown
Mostly it's there or it isn't. A few times it has started out OK, then delivers what feels like maybe 1/2 max boost before no boost. Well I was wondering what else the ECU looks at for BC operation - components I can check. You are right about a thorough check out of the wiring, thanks.
Skillet is offline  
post #6 of 15 Old 09-20-2010, 01:52 PM
WRXtuners Member
 
anxiouz's Avatar
 
Join Date: Sep 2010
Location: California
Posts: 61
anxiouz is an unknown
Any chance that the behavior is temperature related? Like it works fine when the car is cold but when it's hot you start having issues? That would point to IC piping couplers possibly heating up, expanding, and leaking a lil.

Otherwise I'm stumped. It sounds like you've checked everything thoroughly.

And when I was having solenoid issues I was throwing CEL codes. So for you to not be, that's even more strange.
anxiouz is offline  
post #7 of 15 Old 09-22-2010, 08:57 AM Thread Starter
WRXtuners Member
 
Join Date: Apr 2010
Location: Colorado
Posts: 7
Skillet is an unknown
I'd have to say not. I'm considering changing the stock setup at this point - maybe a manual bc. If I have to throw money at it I want to know it's going to work. It's the wife's car & she doesn't hot rod it, so maybe that's an OK option. Thanks for the input.
Skillet is offline  
post #8 of 15 Old 09-22-2010, 09:29 AM
WRXtuners Member
 
basco's Avatar
 
Join Date: Aug 2004
Location: South Carolina
Posts: 1,873
basco is a WRX expert worth listening to basco is a WRX expert worth listening to basco is a WRX expert worth listening to basco is a WRX expert worth listening to basco is a WRX expert worth listening to basco is a WRX expert worth listening to
Send a message via AIM to basco Send a message via MSN to basco
Never is an MBC ok especially without a protune, partial throttle full boost will grenade the hell out of your motor

FP GT35R MoTeC M800 AndrewTech PPG'd Wagon - 513AWHP
06 Mazdaspeed6 280/330
- Matt
basco is offline  
post #9 of 15 Old 10-01-2010, 09:15 AM Thread Starter
WRXtuners Member
 
Join Date: Apr 2010
Location: Colorado
Posts: 7
Skillet is an unknown
Roger that, good advice. I'm gonna buy her a bus pass.
Skillet is offline  
post #10 of 15 Old 01-05-2011, 05:43 PM
WRXtuners Member
 
Join Date: Jan 2011
Location: New Mexico
Posts: 5
tylorsanchez is an unknown
hey guys i need help so me and my friends were messing around halling as in my rex and i blew out my mass flow senser but now my turbo wont kick in and it sounds like its just blowing out like my psi's will not go above 5 even when my turbo is turned up. so i am really lost on were the problem could be. please halp
tylorsanchez is offline  
post #11 of 15 Old 01-05-2011, 10:50 PM
Moderator
 
newtothegame's Avatar
 
Join Date: Dec 2006
Location: Maryland
Posts: 6,493
Images: 4
newtothegame is known to be trustworthy and helpful newtothegame is known to be trustworthy and helpful
Send a message via Yahoo to newtothegame
When your turbo is turned up? What mods, how many miles, what have you checked? More detail/information could help us help you much better and quicker.

Joshua
"2007 WRX- PPG'd, 20G- Tim Bailey tuned
Stage 2 2005 WRX
Cobbtuning.com"
newtothegame is offline  
post #12 of 15 Old 01-06-2011, 08:18 PM
WRXtuners Member
 
Join Date: Jan 2011
Location: New Mexico
Posts: 5
tylorsanchez is an unknown
alright well is an 02 with about 90 k on it but it has no big mods i have done nothing sense i bought it andthe guy who had it befor me did nothing sorry man dont have this engine figured out yet so just throw me ideas
tylorsanchez is offline  
post #13 of 15 Old 01-07-2011, 06:20 AM
WRXtuners Member
 
Join Date: Jun 2007
Location: Texas
Posts: 4,981
pzr2874 is known to be trustworthy and helpful pzr2874 is known to be trustworthy and helpful
Start your own thread and more people will respond and help you

Paul
2002 WRX Sold
2007 WRX Sold
2007 STi totaled
2007 Foz XT sold
2007 MS3
pzr2874 is offline  
post #14 of 15 Old 03-05-2011, 12:49 AM
WRXtuners Member
 
WRXGurl's Avatar
 
Join Date: Mar 2011
Location: Ohio
Posts: 4
WRXGurl is an unknown
I've had the same problem on my 03 as the original poster... I will boost under half throttle but it will go to .07 bars and stay. It feels as though it has no power and the boost will not budge about this. I have a turbo timer and aftermarket BOV but I have checked my system and it's not leaking. Other days it will boost to .1 bar and hold beautifully... next min it pegs at .07 and starts dogging. When I bought the car it has a Subaru tuning sticker on it but can't find anyone local to reflash... it has 178,000 miles and runs strong. Just looking for Ideas since all the info on the solenoid says it wouldn't boost all the way with it malfunctioning and I have no CEL other than the occasional P0420 due to my cobb exhaust.. any ideas?
WRXGurl is offline  
post #15 of 15 Old 03-05-2011, 09:23 AM
WRXpert
 
dumdum's Avatar
 
Join Date: Sep 2004
Location: Virginia
Posts: 2,800
Images: 12
dumdum is a WRX tech God, pay attention dumdum is a WRX tech God, pay attention dumdum is a WRX tech God, pay attention dumdum is a WRX tech God, pay attention dumdum is a WRX tech God, pay attention dumdum is a WRX tech God, pay attention dumdum is a WRX tech God, pay attention dumdum is a WRX tech God, pay attention
You said you have a cable and a logging program. Log the car and see what the IAM is and if it dropping. You need to list ALL performance mods done to the car. If the car has been modded and not tuned for the particular parts then your going to have issues. I can already tell there is no EM because you have a CEL/DTC for the exhaust. Read this.........
Unabomber's Manifesto - NASIOC

Homebrewed tuned with Opensource!
dumdum is offline  
Sponsored Links
Advertisement
 
Reply


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



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 Off
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome