boost won't increase.

dannys35 · 03-11-2010, 08:29 PM

The pics are in my albums section.

cre · 03-12-2010, 01:21 AM

Is it stumbling when you hit 12psi?

btwilson86 · 03-12-2010, 08:08 AM

This was sent in a PM to dannys35, but thought I'd post it here so that anyone else having a similar problem will be able to get some info from this thread:

On the front side of the turbo, towards the bottom of it there should be a round disk with a vacuum line coming out of it. This is your wastegate actuator (this controls when the wastegate opens, which regulates how high or low your turbo will spool). When routed properly, this vacuum line will have the other end of it connect to an intake hose that receives boost (don't remember where the factory one is, but it's after the turbo). What you want to do is put your mbc (manual boost controller) in this vacuum line. This way the mbc can restrict the flow of the boosted air to the wastegate actuator, causing it to open less and later, resulting in higher boost.

With that said, you should definitely check for any vacuum leaks or degrading hose couplers, etc. that can result in leaking boost. Any boost leak will cause a higher work load on the turbo, which could drastically shorten it's life. This is also important because as I understand it 12 psi is near the upper limits of the stock fuel delivery system, which means you'll start running lean and hit fuel cut

dannys35 · 03-12-2010, 04:22 PM

Yes cre it stumbles though all the boost range and if you have it in 5th gear doing 60MPH you have to down shift or it starts to shake and stumble and wont go any faster I am confused with that. I guess it may be the clutch what kind of clutch do you suggest that I get.

btwilson86 · 03-12-2010, 06:34 PM

Before you jump into your clutch, check for codes.

cre · 03-13-2010, 02:26 AM

I'm thinking fuel cut... or a knock problem... possibly both. Definitely check the codes as BT says.

btwilson86 · 03-13-2010, 08:01 AM

And after checking your new pics in your album, you have a hacked together vacuum system. Looks like you'll need to spend a little time and start routing your vacuum lines properly. After reading your other post, looks like Green7mgte gave you a couple of vacuum line routing diagrams

03-12-2010, 01:21 AM	#2
cre Toyota Racing Development Join Date: Apr 2007 Posts: 5,038	Is it stumbling when you hit 12psi? __________________ If something breaks or you need to contact a member of the administration please post HERE. Unless it's a private or administration matter please post it on the forum. It benefits no one else if car related questions aren't posted for future users and takes away from the time I'm able to spend helping on the rest of the forum. If you're so inclined I'm always more than happy to accept tips via PayPal. Tip Jar --->

03-12-2010, 08:08 AM	#3
btwilson86 Super Moderator Join Date: May 2007 Location: Billings, Montana Posts: 1,034	This was sent in a PM to dannys35, but thought I'd post it here so that anyone else having a similar problem will be able to get some info from this thread: On the front side of the turbo, towards the bottom of it there should be a round disk with a vacuum line coming out of it. This is your wastegate actuator (this controls when the wastegate opens, which regulates how high or low your turbo will spool). When routed properly, this vacuum line will have the other end of it connect to an intake hose that receives boost (don't remember where the factory one is, but it's after the turbo). What you want to do is put your mbc (manual boost controller) in this vacuum line. This way the mbc can restrict the flow of the boosted air to the wastegate actuator, causing it to open less and later, resulting in higher boost. With that said, you should definitely check for any vacuum leaks or degrading hose couplers, etc. that can result in leaking boost. Any boost leak will cause a higher work load on the turbo, which could drastically shorten it's life. This is also important because as I understand it 12 psi is near the upper limits of the stock fuel delivery system, which means you'll start running lean and hit fuel cut __________________ 1989 7MGTE R154 Targa Top White Package w/Blue Interior Driftmotion 57trim CT26, Upgraded Intercooler, 2.25" Hard Pipes, 3" Turbo Back Exhaust with Test Pipe, HKS VPC w/GM 3 bar MAP sensor, APEXi S-AFC, Walbro 255lph fuel pump, ProSport EVO Series Boost / Fuel Pressure / AFR gauges, Lotek a Pillar Gauge Pod, HKS Type 0 Turbo Timer, Eibach Lowering Springs, Tokico Illumina II TEMS struts, custom powder coated Motegi Racing TrakLite wheels

03-12-2010, 06:34 PM	#5
btwilson86 Super Moderator Join Date: May 2007 Location: Billings, Montana Posts: 1,034	Before you jump into your clutch, check for codes. __________________ 1989 7MGTE R154 Targa Top White Package w/Blue Interior Driftmotion 57trim CT26, Upgraded Intercooler, 2.25" Hard Pipes, 3" Turbo Back Exhaust with Test Pipe, HKS VPC w/GM 3 bar MAP sensor, APEXi S-AFC, Walbro 255lph fuel pump, ProSport EVO Series Boost / Fuel Pressure / AFR gauges, Lotek a Pillar Gauge Pod, HKS Type 0 Turbo Timer, Eibach Lowering Springs, Tokico Illumina II TEMS struts, custom powder coated Motegi Racing TrakLite wheels

03-13-2010, 02:26 AM	#6
cre Toyota Racing Development Join Date: Apr 2007 Posts: 5,038	I'm thinking fuel cut... or a knock problem... possibly both. Definitely check the codes as BT says. __________________ If something breaks or you need to contact a member of the administration please post HERE. Unless it's a private or administration matter please post it on the forum. It benefits no one else if car related questions aren't posted for future users and takes away from the time I'm able to spend helping on the rest of the forum. If you're so inclined I'm always more than happy to accept tips via PayPal. Tip Jar --->

03-13-2010, 08:01 AM	#7
btwilson86 Super Moderator Join Date: May 2007 Location: Billings, Montana Posts: 1,034	And after checking your new pics in your album, you have a hacked together vacuum system. Looks like you'll need to spend a little time and start routing your vacuum lines properly. After reading your other post, looks like Green7mgte gave you a couple of vacuum line routing diagrams __________________ 1989 7MGTE R154 Targa Top White Package w/Blue Interior Driftmotion 57trim CT26, Upgraded Intercooler, 2.25" Hard Pipes, 3" Turbo Back Exhaust with Test Pipe, HKS VPC w/GM 3 bar MAP sensor, APEXi S-AFC, Walbro 255lph fuel pump, ProSport EVO Series Boost / Fuel Pressure / AFR gauges, Lotek a Pillar Gauge Pod, HKS Type 0 Turbo Timer, Eibach Lowering Springs, Tokico Illumina II TEMS struts, custom powder coated Motegi Racing TrakLite wheels

03-11-2010, 08:29 PM	#1
dannys35 Intake Join Date: Feb 2010 Location: Carthage NC Posts: 33	The pics are in my albums section.

03-12-2010, 04:22 PM	#4
dannys35 Intake Join Date: Feb 2010 Location: Carthage NC Posts: 33	Yes cre it stumbles though all the boost range and if you have it in 5th gear doing 60MPH you have to down shift or it starts to shake and stumble and wont go any faster I am confused with that. I guess it may be the clutch what kind of clutch do you suggest that I get.

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