Welcome to the North American Subaru Impreza Owners Club Thursday August 21, 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 > Engine Management & Tuning

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 01-26-2006, 11:54 AM   #1
cjfike
Scooby Newbie
 
Member#: 60116
Join Date: Apr 2004
Location: (ab)Normal IL
Vehicle:
1999 RS Coupe
Silver Thorn

Question JDM ECU paired with US ECU - pro & cons

Noticed on some vendor sites where they pair the ECU's. It sounds like it would be a good thing, if it really works.

Has anyone heard good or bad about this?
* Registered users of the site do not see these ads.
cjfike is offline   Reply With Quote
Old 01-26-2006, 12:17 PM   #2
mrbell
Scooby Specialist
 
Member#: 1871
Join Date: Jul 2000
Location: Salt Lake City, UT
Vehicle:
2000 Impreza 2.5RS
Blue Ridge Pearl

Default

Pair? As in run both ECU's at the same time?
mrbell is offline   Reply With Quote
Old 01-27-2006, 12:06 AM   #3
cjfike
Scooby Newbie
 
Member#: 60116
Join Date: Apr 2004
Location: (ab)Normal IL
Vehicle:
1999 RS Coupe
Silver Thorn

Default

Yes. A site I visited had this wiring harness which brought both ecu's into play. It was unclear how they interacted, engine control was coming from the original JDM ecu.
cjfike is offline   Reply With Quote
Old 01-27-2006, 12:17 AM   #4
Jaxx
NASIOC Supporter
 
Member#: 177
Join Date: Aug 1999
Chapter/Region: NWIC
Location: Boise,Idaho,USA
Vehicle:
The 93 Imp W/EJ20K
flat black

Default

no bad idea
Jaxx is offline   Reply With Quote
Old 01-27-2006, 09:14 AM   #5
ride5000
Scooby Guru
 
Member#: 32792
Join Date: Feb 2003
Chapter/Region: NESIC
Location: lincoln, ri
Vehicle:
2003 GGA MBP
12.9 / 105+

Default

got a link?
ride5000 is offline   Reply With Quote
Old 01-27-2006, 09:40 AM   #6
8Complex

Moderator
 
Member#: 922
Join Date: Feb 2000
Chapter/Region: MWSOC
Location: Schaumburg, IL
Vehicle:
04 FXT
Red

Default

That is pretty useless unless you have a system that is unable to be flashed, and have to replace it's fueling/timing abilities with that of a standalone.

'Bad idea' is putting it nicely.
8Complex is offline   Reply With Quote
Old 01-27-2006, 10:04 AM   #7
RickInLittleElm
Scooby Specialist
 
Member#: 58353
Join Date: Mar 2004
Chapter/Region: TXIC
Location: DFW - the north side
Vehicle:
99 Mercedes-Benz
E430

Default

I am unclear as to the actual benefit of this. Anyone have some insight as to why this is done?
RickInLittleElm is offline   Reply With Quote
Old 01-27-2006, 10:40 AM   #8
Freon
Scooby Specialist
 
Member#: 88322
Join Date: Jun 2005
Chapter/Region: MWSOC
Location: Indianapolis, IN
Vehicle:
2009 BMW 135i

Default

The only reason I can see to do this would be if you did a full factory stock JDM swap, but needed to pass US emissions.

I have toyed with the idea of using a second ECU to control extra devices, like WI/alcohol injection, once all the free flashing tools are working well. The stock ECU is very powerful, its just a matter of being able to make it do what you want.
Freon is offline   Reply With Quote
Old 01-27-2006, 10:42 AM   #9
Jaxx
NASIOC Supporter
 
Member#: 177
Join Date: Aug 1999
Chapter/Region: NWIC
Location: Boise,Idaho,USA
Vehicle:
The 93 Imp W/EJ20K
flat black

Default

ok ill expand the only place its a good idea is something like mine

the stock ecu is running the fuel pump relays creating the tach signal turning the fans on and off
i have second ecu (tec2) and second crank sensor that control the fuel and spark functions
it works ok .. but its not my daily driver
Jaxx is offline   Reply With Quote
Old 01-27-2006, 11:10 AM   #10
cjfike
Scooby Newbie
 
Member#: 60116
Join Date: Apr 2004
Location: (ab)Normal IL
Vehicle:
1999 RS Coupe
Silver Thorn

Default

Passing emissions is certainly a positive. Although bad idea was my first thought also, emissions was the thing that came to mind. Still I cannot imagine how one ECU could control the engine, and the other would just be controlling US emissions compliance. Unless it is simply powered up and waving it's arms screaming "I AM OBD-II"!
cjfike is offline   Reply With Quote
Old 01-27-2006, 11:54 AM   #11
mrbell
Scooby Specialist
 
Member#: 1871
Join Date: Jul 2000
Location: Salt Lake City, UT
Vehicle:
2000 Impreza 2.5RS
Blue Ridge Pearl

Default

You probalby wouldn't pass emissions. You have two options with this, really. One, trying to drive 2 ECU's w/ one set of sensors will certainly throw 'Circuit High' codes all over the place. Or disconnect the US ECU from the sensors, and then you get 'Circuit not ready' codes all over the place. If your county does OBD-II testing, then you won't pass with these codes. If they don't do OBD-II testing, you dont' have to worry about it anyway.
mrbell is offline   Reply With Quote
Old 01-27-2006, 01:34 PM   #12
Jaxx
NASIOC Supporter
 
Member#: 177
Join Date: Aug 1999
Chapter/Region: NWIC
Location: Boise,Idaho,USA
Vehicle:
The 93 Imp W/EJ20K
flat black

Default

there is nooooo way it will pass obd-2 emmissions zero

if you don't have to do obd-2 just run the jdm ecu ...
Jaxx is offline   Reply With Quote
Old 01-28-2006, 12:12 AM   #13
cjfike
Scooby Newbie
 
Member#: 60116
Join Date: Apr 2004
Location: (ab)Normal IL
Vehicle:
1999 RS Coupe
Silver Thorn

Default

COOL beans man!

How would one go about asking the county if they do OBD-II testing? I guess I could walk into a test center and ask. Fairfield CT is a very odd place. Backward in alot areas you would not expect; then on the cutting edge of what you don't expect.
cjfike 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
JDM EJ25 vs USDM EJ25, pros & cons ? qtr_wrx Subaru Conversions 9 05-25-2009 12:10 AM
Using JDM heads/cams with US sensors/ECU, heres how... Invisiguard Factory 2.5L Turbo Powertrain 15 08-20-2006 12:19 PM
The End of the Cold War & the Disintregration of the USSR... pros & cons? Asinine Political Playground 14 10-07-2004 07:17 PM
Aftermarket clutch & LWFW - Pro & Cons STi4life Transmission (AT/MT) & Driveline 3 03-17-2004 10:17 AM
Fuel pump on a N/A: pros & cons please Evil-Mastermind Normally Aspirated Powertrain 5 03-08-2001 08:50 AM


All times are GMT -4. The time now is 09:36 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.