Welcome to the North American Subaru Impreza Owners Club Monday September 22, 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 > Pre-2002 Factory 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 09-04-2005, 06:05 PM   #1
peters14gc
Scooby Newbie
 
Member#: 90826
Join Date: Jul 2005
Location: MoCo, Fred neck, MD
Vehicle:
1997 -S14, +GC8
-blue, +grey

Default underboosting in jdm ej207t v.5.

Hey guys... just wanted to inquire upon your wisdom regarding underboosting.

I've searched the forums and could not find anything specific to my problem but close, and i have looked into the few possibilities that were laid out but have yet to solve the problem

I have a jdm v.5 sti motor, 2 days it ago it was making 17psi-19psi max boost depending on gear and rmp.

Yesterday while driving down I270 and hitting WOT i noticed it was a lil slower.

I checked the boost and i was only getting about 10psi or so.

So what ive checked so far is driving until i hit full boost, i hit full boost right now at 10psi around 3500-4000 rpm which was normal when i was able to boost at 19psi. But instead of the boost climbing it stops at 10psi.

Driving up until then 10psi and up the rpm feels normal, the motor still pulls like before. its just the boost stops at 10psi.

So we visually checked the vaccum hoses, no disconnections or visual leaks. Intercooler and everything looks fine.

I even emptied the oil catch can, but the can didnt seem clogged or anything, air can freely move in it. I then check the intake and noticed that the clamp from intake to turbo was broken, so i tighten it. check everything else. Reset the ECU and drove...

Since there was no intake leak anymore the cars response was better, but then the underboost issue is still there.

I know that underboosting can be caused by wastegate, blow off valve or bad boost solenoid other than vacuums. Is there any else i can do to check or any other factors i can look into and ways to check these mechanical issues so that i get my boost back?

any help is appreciated, thanks guys.

-peter.
* Registered users of the site do not see these ads.

Last edited by peters14gc; 09-04-2005 at 06:13 PM.
peters14gc is offline   Reply With Quote
Old 09-05-2005, 03:28 PM   #2
eastcoastbumps
Scooby Guru
 
Member#: 29201
Join Date: Nov 2002
Chapter/Region: NESIC
Location: Shrewsbury, MA
Vehicle:
BMW M3
Honda S2000x2

Default

I don't want to scare you but you should do a compression check if the hose (rather than the clamp) came off the turbo inlet. The turbo will pull in un-metered air that the MAF didn't read. You could have been running dangerously lean.

About the boost, 10psi is roughly wastegate boost. So you could have an electrical problem, rather than a vacuum problem. Hook up a scan tool and see if there are any codes. Check your wiring going to the wastegate solenoid. An EGT too high code, from running lean, may cause the ECU to limit boost to wastegate boost.

Pete
eastcoastbumps is offline   Reply With Quote
Old 09-06-2005, 09:55 AM   #3
peters14gc
Scooby Newbie
 
Member#: 90826
Join Date: Jul 2005
Location: MoCo, Fred neck, MD
Vehicle:
1997 -S14, +GC8
-blue, +grey

Default

Quote:
Originally Posted by eastcoastbumps
I don't want to scare you but you should do a compression check if the hose (rather than the clamp) came off the turbo inlet.
Pete
Yeah... the hose never came off, it was still on turbo inlet all the way with being pushed off or hanging off or anything.

I just fixed the clamp and tightened it.

And its a jdm ecu and the obd II will not read. so scanning wont work.

Last edited by peters14gc; 09-06-2005 at 10:01 AM.
peters14gc is offline   Reply With Quote
Old 09-06-2005, 09:27 PM   #4
peters14gc
Scooby Newbie
 
Member#: 90826
Join Date: Jul 2005
Location: MoCo, Fred neck, MD
Vehicle:
1997 -S14, +GC8
-blue, +grey

Default

thanks for all the advice guys... im actually boosting normally now. I guess sundays ECU reset took some time to figure things out after i fixed the intake issue.

feels good around 17-20psi again.
peters14gc 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

Similar Threads
Thread Thread Starter Forum Replies Last Post
MD: Gauging interest in JDM Forester 2.5 shortblock (same as STi) with ~4000 miles StealthWRX Private 'For Sale' Classifieds 37 01-12-2006 09:33 PM
Gauging interest in JDM Ver. 5 WRX motor b57m57w57 Private 'For Sale' Classifieds 48 11-12-2005 01:56 PM
underboosting in a jdm sti v.5 motor. peters14gc Factory 2.0L Turbo Powertrain 11 09-07-2005 12:11 AM
underboosting in a jdm sti v.5 motor. peters14gc Mid Atlantic Impreza Club -- MAIC 4 09-06-2005 09:27 PM
04 JDM Sti headlight in an 04 2.5 RS? digi Interior & Exterior Modification 11 11-30-2003 05:18 AM


All times are GMT -4. The time now is 03:16 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.