Welcome to the North American Subaru Impreza Owners Club Saturday December 20, 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 > Factory 2.0L Turbo Powertrain (EJ Series Factory 2.0L Turbo)

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 04-29-2006, 04:35 AM   #1
STUDAndring
Scooby Newbie
 
Member#: 61891
Join Date: May 2004
Location: Kennewick, WA
Vehicle:
04 WRX
Pearl Blue

Question EGT Problem or ECU Problem???

OK where to start......I have a check engine light on, like most of us that mod are cars do. Well my car, when doing a pull from 3grand to redline is only hitting 8PSI. I took to subaru and they told me that the EGT is reading temps are too high so the ECU is going into some kind of safe mod and limitin boost. They say when they unplug the EGT it still has the error so it must be a internall ECU malfunction. They will not cover it under warrent because at one time it was flashed by COBB but now it is stock again, with just a turbo back exhaust.(forgot to remove the sticker from ECU that was mailed to me from COBB...mybad) Anyhow I took my car to a guy in town that all he does is work on Lean mean hot rods and boosted cars.(his name is ROD for god sake he knows his stuff) He looked at what subaru said they did to diagnos and he told me that it is not the ECU but the EGT sensor itself that is the problem because if the EGT is reading too hot or is unplugged you would get the same check engine. Anyhow if you have any know how on that stuff please input it for me.

In the mean time I am going to swap my EGT with my buddys '02 WRX. And see if it fixs things. If it throws his Check engine light then I will know it was the EGT. Couple questions about doing that.

1. Is the EGT sensor the same for '02 and '04?
2. What is the best way to get a wrentch on it? I was havin no luck coming from the side the air box was on. Maybe I should come from the bottom or somthing.

Would love to hear some good input on this....thanks
* Registered users of the site do not see these ads.

Last edited by STUDAndring; 04-29-2006 at 04:41 AM.
STUDAndring is offline   Reply With Quote
Old 04-29-2006, 12:32 PM   #2
JRSCCivic98
Scooby Specialist
 
Member#: 67080
Join Date: Jul 2004
Default

If you set a CEL for EGT too high (usually happens if you have a catless uppipe) you run the chance of the ECU switching to low boost because it characterizes high EGT with det and hence drops your IAM and once that drops below a certain level (usually 6) the boost control is completely turned off by the ECU and you run wastegate pressure.

Now, if you have a stock uppipe with a CAT still in it, replaced the EGT probe... it's probably gone bad. If you have a catless uppipe and you don't plan on getting EM (dunno why you took the AP off anyway) then do the ghetto resistor mod on the EGT sensor harness. If you had a way of logging you could verify that your ECU is really the one turning off the boost control.

Also, what the dealership told you about unplugging the EGT and hoping that would cause the car/ECU to behave differently is not correct. Unplugging the EGT sensor is pretty much the same as having a bad EGT sensor (which makes the temp look very high to the ECU) which causes it to behave like I said above.
JRSCCivic98 is offline   Reply With Quote
Old 04-29-2006, 12:35 PM   #3
djviper
Scooby Specialist
 
Member#: 107276
Join Date: Feb 2006
Location: north london England
Vehicle:
99 V.R.Special
WRC blue

Default

+1 for what JRS said

lazy arse scooby dealers!
djviper is offline   Reply With Quote
Old 04-29-2006, 04:46 PM   #4
STUDAndring
Scooby Newbie
 
Member#: 61891
Join Date: May 2004
Location: Kennewick, WA
Vehicle:
04 WRX
Pearl Blue

Default

I do have a catless uppipe. What is the easyest way to fix the CEL. How do I do a resistor mod. SO the car will think it is ok. Maybe you guys have a site to refer me to.

Thanks for the input so far.
STUDAndring is offline   Reply With Quote
Old 04-29-2006, 04:52 PM   #5
Mulder
Trust no one
Moderator
 
Member#: 11170
Join Date: Oct 2001
Chapter/Region: Tri-State
Location: NYC
Vehicle:
02 WRX
15 WRX/05 GTO

Default

Actually a high EGT reading corresponds to a low resistance across the probe. If the probe is not present the resistance reading will be infinite which appears to the ECU as an abnormally LOW EGT reading. The code that is usually set for this condition is P0546. If you get a code for high EGT temps (NOT circuit high which is the exact opposite) with no probe present, it may be due to a short in the wiring.
It would be helpful if you could post the exact code that was set.
Mulder is offline   Reply With Quote
Old 04-29-2006, 05:26 PM   #6
STUDAndring
Scooby Newbie
 
Member#: 61891
Join Date: May 2004
Location: Kennewick, WA
Vehicle:
04 WRX
Pearl Blue

Default

As I understand it low or no resistance will resort in a high EGT reading. High resistance is low EGT reading. So Not pluged in would be a high EGT CEL because there would be no resistance.
STUDAndring is offline   Reply With Quote
Old 04-29-2006, 05:27 PM   #7
Mulder
Trust no one
Moderator
 
Member#: 11170
Join Date: Oct 2001
Chapter/Region: Tri-State
Location: NYC
Vehicle:
02 WRX
15 WRX/05 GTO

Default

Quote:
Originally Posted by STUDAndring
As I understand it low or no resistance will resort in a high EGT reading. High resistance is low EGT reading. So Not pluged in would be a high EGT CEL because there would be no resistance.
No probe = infinite resistance which reads as very low EGT temp.
Mulder is offline   Reply With Quote
Old 04-29-2006, 06:39 PM   #8
STUDAndring
Scooby Newbie
 
Member#: 61891
Join Date: May 2004
Location: Kennewick, WA
Vehicle:
04 WRX
Pearl Blue

Default

well any how. How do I mod it to tell the car that the EGT is fine so It will not have the CEL anymore and allow it to boost to be full again.
STUDAndring is offline   Reply With Quote
Old 04-29-2006, 11:01 PM   #9
JRSCCivic98
Scooby Specialist
 
Member#: 67080
Join Date: Jul 2004
Default

Correct/Proper answer = Get it tune (that means get something for EM)
Incorrect/Cheap answer = do a search for "resistor mod" and put a resistor in the EGT sensor harness.
JRSCCivic98 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
HID harness problem or Fan problem? Striker13 Electrical & Lighting 8 12-07-2006 02:43 PM
Too small injectors, or ecu problems? reddevil Engine Management & Tuning 5 10-28-2006 05:23 AM
Clutch problem or tuning problem? earlmale Transmission (AT/MT) & Driveline 3 02-21-2006 01:24 AM
Web problem or my problem? No search? RyeDaddy General Community 2 08-22-2003 01:17 PM
I think I've got some fuel problems or ECU is screwed up. Maybe a bad sensor too(MAF) GregUnd Texas Impreza Club Forum -- TXIC 22 04-03-2003 01:23 PM


All times are GMT -4. The time now is 10:28 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.