WRX 2.0 wont boost over 4lbs

TPPERFORMANCE · 07-01-2010, 07:13 PM

WRX 2.0 turbo
we have just bought this car. motor has been gone through. the turbo was replaced with a good used turbo STOCK. the up pipe was taken off and the cat was taken out of it.

the problem is the car is lacking boost it will only boost 4 lbs and even that it is having a hard time with

i have check all the hose routing and the intercooler. no leaks no intake leaks either. one thing i am changing is the BOV someone put a aftermarket one on that vent out. im going back to stock but have not gotten it yet.

does anyone have any ideas on why the car wont boost.

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jerbull88 · 07-01-2010, 08:15 PM

pre turbo exhaust leaks? tried a different bcs? all hoses routed correctly? what mods?

TPPERFORMANCE · 07-01-2010, 08:32 PM

no exhaust leak
all hoses are correct
motor is stock on mod is uppipe cat removed
and it had a BOV i just got the stock one installing it right now.
no i havent tried a new BCS

Jermus · 07-01-2010, 09:04 PM

Theres a pretty good chance it could be that BOV. I've seen a few members on here that went back to stock BPV and found better performance with boost and lost other intermittent issues, but of course lose that "cool" sound too.

Let us know if that helps your issue.

TPPERFORMANCE · 07-01-2010, 09:54 PM

Went back to stock valve no gain I'm boost. I just don't know what it could be.

maxpowr · 07-01-2010, 10:39 PM

tgv motors working?

Fierysun · 07-01-2010, 10:53 PM

Try a different factory EBCS.

TPPERFORMANCE · 07-01-2010, 11:09 PM

Tgv???

I'll see if I can get ahold of another bcs

TPPERFORMANCE · 07-01-2010, 11:11 PM

If I hook up the in and out line on the bcs shouldn't I be able to bypass the bcs and make boost?

maxpowr · 07-01-2010, 11:20 PM

run a line from the compressor housing to the wastegate actuator. = boosting spring pressure.

i have heard a broken tgv motor stuck shut can effect being able to boost.

any idle oscillation?

TPPERFORMANCE · 07-01-2010, 11:57 PM

I'll try to hook a line from the comp to the waste gate. When I do this just remove the stock lines going to the bcs right?

What is the tgv motor?
No the idle is good the car runs great other then a lack of power/boost

XanRules · 07-02-2010, 12:00 AM

Any CELs?

TPPERFORMANCE · 07-02-2010, 12:51 AM

Nope nothing

maxpowr · 07-02-2010, 12:56 AM

yeah if you hook up a line from the compressor housing to the wastegate actuator you are no longer controlling boost with electronics. you should get a code from disconnecting the ebc but we are only trying to determine if you can actually make boost mechanically.

you have two tumble generator valves. they are cold start flappers that are below the intake manifold the above the block. the fuel rails are bolted to and the injectors go into the tgv. on either side you have a motor and a sensor. people remove the flapper/motor assembly for improved air flow through the manifold. it is only used as a choke for cold start.

i have heard of these motors failing ,and sticking shut since they are presprung. this flapper being closed makes for very poor air flow for 2 of the four cylinders. can't be good. i can also imagine this causing idling issues which is why i asked.

someone correct me if i'm wrong.

WRXorcism · 07-02-2010, 02:59 AM

Yea there would be other problems if one of the flappers was stuck on either of the tgvs...tumble generator valves

maxpowr · 07-02-2010, 10:37 AM

fixed...thanks.

after discussing this further its been concluded that even if the motor on the tgv was off the airflow would still push it open even at idle so that may be a dead issue. otherwise the motor would misfire like mad...which makes sense.

we are trouble shooting a friends car that is not making boost so i'm in the same boat here...looking for ideas.

we are gonna look into ehaust leaks tomorrow...i'll keep you updated.

TPPERFORMANCE · 07-02-2010, 10:42 AM

can anyone post a diagram of the hose routing for a stock boost control solenoid

Mr.Sub · 07-02-2010, 11:41 AM

here's something for you to check.

I had a friend with a Lexus GS300 NA-T setup who normally would run at 12psi. For some reason, for 3 months he would max out at 4psi. He checked everything, from putting in new wastegates and BOVs to pressure testing the block and intercooler pipes.

It ended up being a clogged cat in the exhaust. I'd check that out in addition to everything else you might be planning on checking

treefan · 07-02-2010, 12:47 PM

I had an issue like that with mine after i replaced the hoses for the bcs and removed the restrictor pellet. After that it would only hit 5-6lbs. boost and spuraticly at best. I got a grimspeed bcs which doesn't require the pellet just a retune. along with my supporting mods I peak at 20lbs.

07-01-2010, 07:13 PM	#1
TPPERFORMANCE Scooby Newbie Member#: 250906 Join Date: Jul 2010	WRX 2.0 wont boost over 4lbs WRX 2.0 turbo we have just bought this car. motor has been gone through. the turbo was replaced with a good used turbo STOCK. the up pipe was taken off and the cat was taken out of it. the problem is the car is lacking boost it will only boost 4 lbs and even that it is having a hard time with i have check all the hose routing and the intercooler. no leaks no intake leaks either. one thing i am changing is the BOV someone put a aftermarket one on that vent out. im going back to stock but have not gotten it yet. does anyone have any ideas on why the car wont boost. * Registered users of the site do not see these ads.

07-02-2010, 12:56 AM	#14
maxpowr Scooby Guru Member#: 159243 Join Date: Sep 2007 Chapter/Region: Tri-State Location: medford nj 08055 Vehicle: 5/01 bugeye Hakt Ecu is back!	yeah if you hook up a line from the compressor housing to the wastegate actuator you are no longer controlling boost with electronics. you should get a code from disconnecting the ebc but we are only trying to determine if you can actually make boost mechanically. you have two tumble generator valves. they are cold start flappers that are below the intake manifold the above the block. the fuel rails are bolted to and the injectors go into the tgv. on either side you have a motor and a sensor. people remove the flapper/motor assembly for improved air flow through the manifold. it is only used as a choke for cold start. i have heard of these motors failing ,and sticking shut since they are presprung. this flapper being closed makes for very poor air flow for 2 of the four cylinders. can't be good. i can also imagine this causing idling issues which is why i asked. someone correct me if i'm wrong. Last edited by maxpowr; 07-02-2010 at 10:34 AM.

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07-01-2010, 08:15 PM	#2
jerbull88 Scooby Newbie Member#: 248089 Join Date: May 2010 Location: albany, ga Vehicle: 2015 sti metallic grey	pre turbo exhaust leaks? tried a different bcs? all hoses routed correctly? what mods?

07-01-2010, 08:32 PM	#3
TPPERFORMANCE Scooby Newbie Member#: 250906 Join Date: Jul 2010	no exhaust leak all hoses are correct motor is stock on mod is uppipe cat removed and it had a BOV i just got the stock one installing it right now. no i havent tried a new BCS

07-01-2010, 09:04 PM	#4
Jermus Scooby Newbie Member#: 241343 Join Date: Mar 2010 Chapter/Region: MWSOC Location: Minnesota Vehicle: 2005 STi CGM	Theres a pretty good chance it could be that BOV. I've seen a few members on here that went back to stock BPV and found better performance with boost and lost other intermittent issues, but of course lose that "cool" sound too. Let us know if that helps your issue.

07-01-2010, 09:54 PM	#5
TPPERFORMANCE Scooby Newbie Member#: 250906 Join Date: Jul 2010	Went back to stock valve no gain I'm boost. I just don't know what it could be.

07-01-2010, 10:39 PM	#6
maxpowr Scooby Guru Member#: 159243 Join Date: Sep 2007 Chapter/Region: Tri-State Location: medford nj 08055 Vehicle: 5/01 bugeye Hakt Ecu is back!	tgv motors working?

07-01-2010, 10:53 PM	#7
Fierysun Scooby Guru Member#: 82745 Join Date: Mar 2005 Chapter/Region: SCIC Location: So Cal Vehicle: 2005 Subaru STI 2003 EJ207 S204 Wagon	Try a different factory EBCS.

07-01-2010, 11:09 PM	#8
TPPERFORMANCE Scooby Newbie Member#: 250906 Join Date: Jul 2010	Tgv??? I'll see if I can get ahold of another bcs

07-01-2010, 11:11 PM	#9
TPPERFORMANCE Scooby Newbie Member#: 250906 Join Date: Jul 2010	If I hook up the in and out line on the bcs shouldn't I be able to bypass the bcs and make boost?

07-01-2010, 11:20 PM	#10
maxpowr Scooby Guru Member#: 159243 Join Date: Sep 2007 Chapter/Region: Tri-State Location: medford nj 08055 Vehicle: 5/01 bugeye Hakt Ecu is back!	run a line from the compressor housing to the wastegate actuator. = boosting spring pressure. i have heard a broken tgv motor stuck shut can effect being able to boost. any idle oscillation?

07-01-2010, 11:57 PM	#11
TPPERFORMANCE Scooby Newbie Member#: 250906 Join Date: Jul 2010	I'll try to hook a line from the comp to the waste gate. When I do this just remove the stock lines going to the bcs right? What is the tgv motor? No the idle is good the car runs great other then a lack of power/boost

07-02-2010, 12:00 AM	#12
XanRules Scooby Guru Member#: 157348 Join Date: Aug 2007 Location: OOoOuuUUUGGGHH!!!!! Vehicle: I Thlammed My Penith in the Car Door	Any CELs?

07-02-2010, 12:51 AM	#13
TPPERFORMANCE Scooby Newbie Member#: 250906 Join Date: Jul 2010	Nope nothing

07-02-2010, 02:59 AM	#15
WRXorcism Scooby Newbie Member#: 111249 Join Date: Mar 2006 Chapter/Region: South East Location: Gainesville, FL Vehicle: '06 WRX	Yea there would be other problems if one of the flappers was stuck on either of the tgvs...tumble generator valves

07-02-2010, 10:37 AM	#16
maxpowr Scooby Guru Member#: 159243 Join Date: Sep 2007 Chapter/Region: Tri-State Location: medford nj 08055 Vehicle: 5/01 bugeye Hakt Ecu is back!	fixed...thanks. after discussing this further its been concluded that even if the motor on the tgv was off the airflow would still push it open even at idle so that may be a dead issue. otherwise the motor would misfire like mad...which makes sense. we are trouble shooting a friends car that is not making boost so i'm in the same boat here...looking for ideas. we are gonna look into ehaust leaks tomorrow...i'll keep you updated.

07-02-2010, 10:42 AM	#17
TPPERFORMANCE Scooby Newbie Member#: 250906 Join Date: Jul 2010	can anyone post a diagram of the hose routing for a stock boost control solenoid

07-02-2010, 11:41 AM	#18
Mr.Sub Scooby Newbie Member#: 238096 Join Date: Feb 2010 Chapter/Region: Tri-State Location: NJ Vehicle: 2002 WRX SRP Stg 2	here's something for you to check. I had a friend with a Lexus GS300 NA-T setup who normally would run at 12psi. For some reason, for 3 months he would max out at 4psi. He checked everything, from putting in new wastegates and BOVs to pressure testing the block and intercooler pipes. It ended up being a clogged cat in the exhaust. I'd check that out in addition to everything else you might be planning on checking

07-02-2010, 12:47 PM	#19
treefan Scooby Newbie Member#: 176856 Join Date: Apr 2008 Chapter/Region: NESIC Location: boston Vehicle: 02 wrx wagon white	I had an issue like that with mine after i replaced the hoses for the bcs and removed the restrictor pellet. After that it would only hit 5-6lbs. boost and spuraticly at best. I got a grimspeed bcs which doesn't require the pellet just a retune. along with my supporting mods I peak at 20lbs.