Welcome to the North American Subaru Impreza Owners Club Monday July 13, 2020
Home Forums Images WikiNASIOC Products Store Modifications Upgrade Garage
NASIOC
Go Back   NASIOC > NASIOC Technical > Factory 2.5L Turbo Powertrain (EJ Series Factory 2.5L 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.







* As an Amazon Associate I earn from qualifying purchases. 
* Registered users of the site do not see these ads. 
Reply
 
Thread Tools Display Modes
Old 04-01-2020, 02:24 PM   #1
What could go wrong
Scooby Newbie
 
Member#: 448908
Join Date: Jun 2016
Default GR ECU issues

So, I had a rod bearing failure (unrelated) and just put in a new engine. The only hardware modifications are the cobb intake and downpipe. It was running rich as hell during startup, it would clean up after a minute or so, then get rough again then die.

They were getting ready to pull the engine again and check the valve clearance, but someone threw a known good ECU in before just for ****s and grins and it fixed things immediately (aside from the fact its probably lean because of the hardware modifications)

Here is where things get weird, the car is on cobb stage 2+, tuned with an AP, the parameters on the old ECU that are wrong (fuel trims or whatever) STAY WRONG

It doesn't matter if we reset the ECU, idle re-learn, uninstall/reinstall the AP, nothing, the parameters stay wrong. Presumably, the ECU isn't totally dead, as the car attempts to start (and runs properly for a little) so it isn't "broken" necessarily, but we can't seem to get things going on the old ecu.

Now as fun as it sounds to basically blow another $1000 on a new ECU, anyone have any advice on getting the old one working? is there like a proper reset of some variety I don't know about?

Thanks in advance for any help ya'll
* Registered users of the site do not see these ads.
What could go wrong is offline   Reply With Quote
Sponsored Links
* Registered users of the site do not see these ads.
Old 04-01-2020, 03:38 PM   #2
spoolinsti05
Scooby Guru
 
Member#: 108051
Join Date: Feb 2006
Chapter/Region: Tri-State
Location: NY
Vehicle:
2005 TickingTimeBomb
Jr tuned TT Sleeved

Default

So you say you swap the ECU and it fixed it? Then it started acting up again with same ecu?
spoolinsti05 is offline   Reply With Quote
Old 04-01-2020, 03:48 PM   #3
spoolinsti05
Scooby Guru
 
Member#: 108051
Join Date: Feb 2006
Chapter/Region: Tri-State
Location: NY
Vehicle:
2005 TickingTimeBomb
Jr tuned TT Sleeved

Default

What you might want to look into is the capacitors. These commonly go bad in electronics.

I had a CSM that had this issue. Yeah not a (dsm) similar however mine was a 4g61t no balance shafts little 1.6L dohc. And the fuel trims would always be off. No matter what tuning I had done. Replaced the capacitors based on a write-up I found and issue was gone.
spoolinsti05 is offline   Reply With Quote
Old 04-01-2020, 09:11 PM   #4
What could go wrong
Scooby Newbie
 
Member#: 448908
Join Date: Jun 2016
Default

Quote:
Originally Posted by spoolinsti05 View Post
What you might want to look into is the capacitors. These commonly go bad in electronics.

I had a CSM that had this issue. Yeah not a (dsm) similar however mine was a 4g61t no balance shafts little 1.6L dohc. And the fuel trims would always be off. No matter what tuning I had done. Replaced the capacitors based on a write-up I found and issue was gone.
Thanks for the help, I'll look into it!
What could go wrong is offline   Reply With Quote
Old 04-10-2020, 01:16 PM   #5
What could go wrong
Scooby Newbie
 
Member#: 448908
Join Date: Jun 2016
Default

I ended up just biting the bullet and getting a new one, didn't want to risk such an important component.

Another symptom it presented with was not correcting AFR. When the engine was running poorly, the AFR was 12ish at idle, but AFR correction wasn't doing anything. Just in case anyone else has a similar problem.

Also, could re-flashing too often have caused this? maybe a bad ground or a bad sensor somewhere? I only ask because I am trying to avoid having this thing crap out on me on the ride home. Thanks guys.
What could go wrong is offline   Reply With Quote
Old 04-10-2020, 04:32 PM   #6
subaru_gc8
Scooby Specialist
 
Member#: 29292
Join Date: Nov 2002
Chapter/Region: SCIC
Location: Orange County CA
Vehicle:
2004 WRX wagon
silver

Default

Quote:
Originally Posted by What could go wrong View Post
I ended up just biting the bullet and getting a new one, didn't want to risk such an important component.

Another symptom it presented with was not correcting AFR. When the engine was running poorly, the AFR was 12ish at idle, but AFR correction wasn't doing anything. Just in case anyone else has a similar problem.

Also, could re-flashing too often have caused this? maybe a bad ground or a bad sensor somewhere? I only ask because I am trying to avoid having this thing crap out on me on the ride home. Thanks guys.
I know on the 02-05 16bit ecus there is limit, but I dont think the other have a flash lilmit. and if you brick it you would know. Sometimes ECUs go bad I ave a JDM one that controls the left head avcs okay but not the right.... so yeah Stupid computer stuff
subaru_gc8 is online now   Reply With Quote
Old 06-27-2020, 10:48 PM   #7
What could go wrong
Scooby Newbie
 
Member#: 448908
Join Date: Jun 2016
Default

Quote:
Originally Posted by subaru_gc8 View Post
I know on the 02-05 16bit ecus there is limit, but I dont think the other have a flash lilmit. and if you brick it you would know. Sometimes ECUs go bad I ave a JDM one that controls the left head avcs okay but not the right.... so yeah Stupid computer stuff
that sucks, it's kinda weird these cars don't have a self-diagnostic for the computer, I wouldn't think it would be spectacularly difficult to implement when there are entire operating systems for PC's that can repair themselves nowadays... granted my car is a decade old but still...
What could go wrong 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

All times are GMT -4. The time now is 02:15 PM.


Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2020, Jelsoft Enterprises Ltd.
Powered by Searchlight © 2020 Axivo Inc.
Copyright ©1999 - 2019, North American Subaru Impreza Owners Club, Inc.

As an Amazon Associate I earn from qualifying purchases.