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Guest Message by DevFuse

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Swapping '90 EJ22 into ODB2 car

ej22 ej25 swap odb1 odb2

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5 replies to this topic

#1 Cyfun


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Posted 26 November 2013 - 07:56 AM

I've done some research, but figured I'd post just to make sure I didn't miss anything.


I'm looking at buying a '90 Legacy parts car, has an EJ22 and FWD auto trans, ridiculously low miles for the price.  In my area, there are tons of late 90s Legacies, Outbacks, and Foresters that have headgasket issues.  I'm wondering how difficult it will be to swap the old OBD1 EJ22 into an OBD2 car, and if there are any years in particular that are easier or flat-out incompatible.


Here's what I know so far. Please correct me if I'm wrong, or feel free to add anything I've missed:

  • I'll need dual-port exhaust manifolds as newer cars are generally single-port.
  • I may want to swap flexplates as the Ej25D's is heavier.
  • I may need to find an intake from an ODB2 EJ22, and the intake from an ODB2 EJ25 wouldn't fit my EJ22.
  • If I use the ODB2 engine harness from the newer car, I'll need to steal a few sensors from the OBD2 engine.
  • The ECU from my '90 Legacy *should* plug in to the OBD2 harness, but the car might run fine with the OBD2 ECU, even if it's from an EJ25D.
  • I can't just plug the ODB1 EJ22 engine harness into the ODB2 car's main harness.
  • I could swap over my entire ODB1 harness into the newer car and forego ODB2 compatibility. My state doesn't do inspections so I don't have to worry about that.
  • I want a car no newer than '99 as the EJ251/Ej252/EJ253/Ej254 are going to be a ton of work to swap from, or not even compatible at all.

#2 johnceggleston


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Posted 26 November 2013 - 08:24 AM

the 90 block and heads will work fine, except for the EGR issue.

buy an intake from a 95 - 98 ej22 with EGR and install it with the 90 ej22.

you will have to do the EGR work around or tap the driver side head for the EGR pipe.

and if it is an auto trans car you have to use the flex plate that matches the auto trans in the car.


the exhaust is a non issue.

DO NOT swap the ECU, it has to match the wiring in the car.


so compare the cost of the 90 ej22 plus the cost of the intake to the cost of a 95 - 98 ej22 w/ EGR.

#3 ivans imports

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Posted 26 November 2013 - 10:43 AM

flex plate is larger bolt pattern make shure it matches converter

#4 ivans imports

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Posted 26 November 2013 - 10:44 AM

smaller the bolt pattern higher the stall

#5 idosubaru


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Posted 26 November 2013 - 12:11 PM

simply install an OBD EJ22 intake manifold and it's all plug and play for DOHC EJ25's and Phase I EJ22's.


EJ25 and EJ18 and 1995 EJ22 vehicles are dual port exhaust.  The rest are Single port exhaust.

EGR has a work around.

Do not touch the ECU.

#6 Gloyale


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Posted 26 November 2013 - 12:23 PM

You don't even need an OBD II manifold.


Just swap the EJ25 intake wiring and throttle body onto the EJ22 intake.



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