underboosting in jdm ej207t v.5.

peters14gc · 09-04-2005, 06:05 PM

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.

eastcoastbumps · 09-05-2005, 03:28 PM

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

peters14gc · 09-06-2005, 09:55 AM

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.

peters14gc · 09-06-2005, 09:27 PM

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.

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	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.

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode

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

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	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

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	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.