lulzcow Posted August 19, 2011 Share Posted August 19, 2011 Howdy yall. I was looking to swap my ecu from the 2.2 which came in my Legacy l to the 2.5 to match my ej25d. curious if this would basically be as easy as swapping the new in for the old, or if ill have to do some wiring work Link to comment Share on other sites More sharing options...
johnegg Posted August 19, 2011 Share Posted August 19, 2011 don't do it. the ecu needs to match the wiring in the car. and you will not gain anything by swapping it out. Link to comment Share on other sites More sharing options...
I Donated broknindarkagain Posted August 19, 2011 I Donated Share Posted August 19, 2011 I believe they are a direct swap. I have ECUs if you need to buy one -broknindarkagain My Current Project - Click Here COME AND TAKE IT "The only thing necessary for the triumph of evil is for good men to do nothing." Link to comment Share on other sites More sharing options...
lulzcow Posted August 19, 2011 Author Share Posted August 19, 2011 hmmmm now im conflicted lulz.... Link to comment Share on other sites More sharing options...
I Donated broknindarkagain Posted August 19, 2011 I Donated Share Posted August 19, 2011 Isn't the wiring nearly iidentical -broknindarkagain My Current Project - Click Here COME AND TAKE IT "The only thing necessary for the triumph of evil is for good men to do nothing." Link to comment Share on other sites More sharing options...
Jab83 Posted August 19, 2011 Share Posted August 19, 2011 it is the same lol.. I'm putting in a 2.2 in place of my 2.5 and keeping the ecu and wire harness its the same. lol. Link to comment Share on other sites More sharing options...
lulzcow Posted August 19, 2011 Author Share Posted August 19, 2011 Then the swap it is! (Would it make ANY difference at all?) Link to comment Share on other sites More sharing options...
bushey45 Posted August 19, 2011 Share Posted August 19, 2011 i've got a frankenmotor in my wagon (2.5 block with 2.2 heads) and it runs no different off the 2.5 ecu than it did off the 2.2 ecu. waste of time imo Link to comment Share on other sites More sharing options...
I Donated broknindarkagain Posted August 20, 2011 I Donated Share Posted August 20, 2011 I don't think there will be any noticeable difference. The fuel mapping is slightly different on the two ECUs....not really enough to make a difference I don't think -broknindarkagain My Current Project - Click Here COME AND TAKE IT "The only thing necessary for the triumph of evil is for good men to do nothing." Link to comment Share on other sites More sharing options...
DOHCEJ22E1 Posted August 20, 2011 Share Posted August 20, 2011 25D ECU = More aggressive fuel trim, higher RPM limit. 22E ECU = Less aggressive fuel trim, lower RPM limit. All in a nutshell. Compatible with either engine from 97 to 98. Link to comment Share on other sites More sharing options...
I Donated broknindarkagain Posted August 20, 2011 I Donated Share Posted August 20, 2011 I forgot about the rev limiter. But yeah, fuel maps is the biggest difference -broknindarkagain My Current Project - Click Here COME AND TAKE IT "The only thing necessary for the triumph of evil is for good men to do nothing." Link to comment Share on other sites More sharing options...
johnegg Posted August 20, 2011 Share Posted August 20, 2011 either ecu will run either engine. the problem is in the wiring, the pins on the ecu. the 98 outback / GT will throw a code if you install a 95 - 97 ecu (L, GT, OBW). so if the ECU is form the same year it may swap fine, i don't know. but if it is from a different year, it will throw a phantom code. is the 2.5 ECU from the same year? what year is the car? what year is the ej25? Link to comment Share on other sites More sharing options...
lulzcow Posted August 21, 2011 Author Share Posted August 21, 2011 the car is a 97 l, with the 97 2.2 ecu, and the guy who built the motor said it had a 96 2.5 block, with 98 heads. kind of a frankenmotor. the main reason im looking is its still running rich after adressing all the bad or dirty sensors, as well as all vacuum seals. no code, just too rich. it has a cheap aftermarket diy intake so the plan to get it running proper was get an intake and computer both designed for my actual motor Link to comment Share on other sites More sharing options...
I Donated broknindarkagain Posted August 22, 2011 I Donated Share Posted August 22, 2011 Does it have DOHC heads? If so, I would suggest using the 2.5 ECU -broknindarkagain My Current Project - Click Here COME AND TAKE IT "The only thing necessary for the triumph of evil is for good men to do nothing." Link to comment Share on other sites More sharing options...
DOHCEJ22E1 Posted August 22, 2011 Share Posted August 22, 2011 the car is a 97 l, with the 97 2.2 ecu, and the guy who built the motor said it had a 96 2.5 block, with 98 heads. kind of a frankenmotor. the main reason im looking is its still running rich after adressing all the bad or dirty sensors, as well as all vacuum seals. no code, just too rich. it has a cheap aftermarket diy intake so the plan to get it running proper was get an intake and computer both designed for my actual motor I do suspect these to be the culprit since this would make a slightly high compression 25D. Have you seen the pistons to the 96s? Designed to CRUSH air/fuel mixture & the 98 heads aren't like the 96 heads at all. 98 heads have bigger intake ports & the quench chamber is a 'clover leaf' style. I'd probably use 89 with such an engine. Cheap aftermarket DIY intakes WILL help make a car thirsty without a doubt since the computer most likely can't cover all of that air coming in. Get a 25D ECU as it's definitely better suited for that engine & has a wider range of fuel trim adjustment w/higher RPM limit. The best intake I've found is keeping your stock air box while using the aftermarket pipe for the upper portion-to-throttle body. Link to comment Share on other sites More sharing options...
lulzcow Posted August 22, 2011 Author Share Posted August 22, 2011 it does have the dohc heads, and i am replacing the cheap diy intake with one designed for our cars. i really wish whoever did this to the car before me hadnt, they deleted the egr sytem, stock airbox, and a few other things. ive got my fingers crossed the legit intake and ecu will right the little wrong in what is otherwise a wonderful car. thank you guys Link to comment Share on other sites More sharing options...
98lgtnc Posted June 7, 2017 Share Posted June 7, 2017 Bump from the dead! Im trying to do an AUTO to Manual swap on my 98 Legacy GT 2.5. Can i use the same wiring harness/ECU between a Legacy Sedan and Wagon? Also does anyone know if the Outbacks will fit as well? Trying to expand my searches in junk yards for these parts. Link to comment Share on other sites More sharing options...
Setnev Posted June 9, 2017 Share Posted June 9, 2017 Yes, an ECU from a compatible 5MT car will work. The only thing is, most auto cars have EGR and most 5MT cars did not, but some later models toward 98/99 did. You need to see if your car has EGR and if the donor ECU has EGR. If the donor does and you don't, you'll throw a CEL, but the other way around is okay because they ECU won't be looking for EGR anyways. Since yours is a 98, you can use just about any ECU from 96-98 Legacy L or GT/Outback/Impreza/Forester 2.2 or 2.5 and the 99 Legacy GT/Outback 2.5 (You cannot use the 99 2.2 ECU. That is a Phase 2 motor and doesn't have the same plugs). Stay away from 95's, even though they were still OBD2, they were the transition year for Subaru to OBD2 and thus I have seen 95's that don't even have the same harnesses. On a side note, 99 Legacy 2.5 and Outback used different ECU's that year. Some ECU's could be used with FreeSSM but I haven't gotten a clear answer on what ECU codes those were. FreeSSM is a program that links your car with your computer using a compatible VAG-COM cable connected to the OBD port and is like a OBD scanner on steroids. Very cool. Link to comment Share on other sites More sharing options...
doublechaz Posted June 9, 2017 Share Posted June 9, 2017 Yep, OBDII-ish. My 95 seems to have later plugs and it talks OBDII out the diag port, but it only has a few of the sensors that would be found in a 96. Plus, if you stay away from 95 ECUs that will leave more for me. Link to comment Share on other sites More sharing options...
Setnev Posted June 9, 2017 Share Posted June 9, 2017 Yep, OBDII-ish. My 95 seems to have later plugs and it talks OBDII out the diag port, but it only has a few of the sensors that would be found in a 96. Plus, if you stay away from 95 ECUs that will leave more for me. Ya, what Chaz said Link to comment Share on other sites More sharing options...
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