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Old 06-06-2008, 02:16 PM   #1
Cautionjump
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Default Ej18 to Ej25 SOHC

Hi guys!
Ive been doing some research on swapping a 2.5RS motor into my 1997 1.8 brighton. I have done the searching and there is tons of info on running the DOHC on the 1..8 ECU. Here is my dillemma.

Ive found a 2.5 RS with ECU and engine wiring harness. If I use the harness and ECU from the 2.5 will I have any issues or will it be pretty much plug and play. ive searched, its just the information is kinda spotty!
Thanks!
Eric
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Old 06-06-2008, 04:00 PM   #2
Storm
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The SOHC is a little more involved, but still doable. Depending on what you motor has for sensors and stuff, most of them if not all, should swap over. Your EJ18 likely doesn't have a knock sensor, so if you want to use the EJ25 ECU, you'll want to add a pin in the plug and run a wire out to the sensor (on the EJ25). If you don't, you'll pop the CEL and noticed it falling flat as timing is pulled.

Jay
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Old 06-06-2008, 04:34 PM   #3
armigerlives
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Heya, I just did this swap last week, it took me 1 day. Your problem spots are going to be the fact that you need change the Injector plugs on the 1.8 harness to the ones from the 2.5. Also, the 2.5 ignitor is combined with the coil pack to you will need to jump wires 1 and5, and 2 and 6 on your curent ignitor plug. Disregard the ignotor because you will be using the one in the 2.5 coil pack. You then replace the 1.8 coil pack plug with the 2.5 plug. Allow yourself xtra wire as it is always helpful in case you have to redo it for some reason. The 2.5 plug has an xtra wire, namely the ground, take this and just ground it by close to the coil pack, all the other wires are the same from the 1.8. Those were the biggest problems I had. BTW, if you have an auto you may need to use to old flex plate because the newer ones are bigger and will not match your trans. The Temp guage is also one you will need to change the plug on. On the 2.5 harness it is a triangular plug, on the 1.8 it is 2 separate plugs. What you do is wire the 2 wire plug into the top 2 wires of the triangular plug, the single wire plug then gets wired into the bottom wire on the triangular plug. any problems you have post them and I will try and help. Sorry if my descriptivness isn't very good.
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Old 06-06-2008, 04:36 PM   #4
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BTW I don't recomend replacing the engine harness all together because it is about 500% more work.
Here is pics of mine car!
http://www.cardomain.com/ride/3088011
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Old 06-06-2008, 08:04 PM   #5
Cautionjump
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Okay that doesnt sound too bad! Will the ECU plug into the harness with no problems? That seems pretty simple, its mostly plug and play aside from switching a few plug and sensor wires?
Thanks!
Eric
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Old 06-06-2008, 08:46 PM   #6
armigerlives
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I do not recomend replacing the ECU because that is where the hearty of the "500% more work will be". the newer ECU has more inputs and outpus than the older harness. Also the ECU controls everything else on your car too. You would be better to change the ENTIRE wiring loom on your car to a newer one if you wanted to use the ECU. That would be a massive pain in the rectal cavity.
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Old 06-06-2008, 10:28 PM   #7
Cautionjump
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Hmmm I wish I could use the ECU with out swapping the entire loom... There has to be a way around that...
Thanks for the help!!!
Eric
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Old 06-07-2008, 10:30 AM   #8
armigerlives
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Also, I remembered this last night, you have to make an adapter and use your throttle body on the 2.5 intake manifold. I use a piece of 20 guage sheet metal. I took the throttle body off the 2.5. Used the gasket to make a template on the sheet metal. Basically, outline the gasket on the sheet metal then mark the bolt holes ans the main hole for airflow. The hole at the top of the gasket is a return for the IAC sensor on the 2.5 throttle body. The adapter needs to close off this hole. So don't cut that one. after it is marked drill your holes and cut it out. When putting the 1.8 throttle body onto the 2.5 manifold use the 2.5 gasket on the manifold side of the adapter, and the 1.8 gasket on the throttle body side of the adapter. I recommend putting permatech on the gaskets so they get a good seal on the adapter.
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Old 06-07-2008, 11:28 AM   #9
Storm
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The 98RS ECU will plug right into your harness. Just add the knock sensor pin and wire it to the sensor. 6500rpm limit and all the potential out of your EJ25 swap!
Quote:
Originally Posted by Cautionjump View Post
Hmmm I wish I could use the ECU with out swapping the entire loom... There has to be a way around that...
Thanks for the help!!!
Eric
Jay
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Old 06-07-2008, 11:40 AM   #10
armigerlives
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storm, would that work on the '93 harness too?
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Old 06-07-2008, 01:07 PM   #11
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No, the 93 has a completely different ECU plug shape. I've found that 96-98 share the same shape, and mostly the same pin-outs between the EJ18, 22 and 25.

Jay Storm
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Old 06-07-2008, 04:42 PM   #12
armigerlives
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K, I have an 2000 forester harness and ECU, maybe I will just swap the whole thing. It isn't soo big of a deal on the car I built. (http://www.cardomain.com/ride/3088011) A few hours to get the new harness ready and maybe 6 hours to switch them out. So I figure a days work.
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Old 06-07-2008, 10:53 PM   #13
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God speed, young man, god speed!!!!

Jay
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Old 06-10-2008, 11:47 AM   #14
bigwillsmall
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Default best way to repower a 95 Legacy Outback?

Hi,
Sorry if it seems like I am hijacking this thread, I hope it is not a problem but I am a new user and the system won't let me post a new one.

I am looking to repower & retranny a 95 Subaru outback which is stock with the 223000 mile SOHC 2.2 engine. From what I can see hassle & satisfaction wise it sounds like a later model 2.5 SOHC would be best and possibly bolt right in. Can anyone confirm this, and tell me what model cars I should attempt to get the engine from? Also any transmission advise would be greatly appreciated. The car is a manual and I imagine getting a 6 speed is not advised but if you have any specific thoughts about that I am curious. Gas mileage is really important to me but power less so, the 2.2 SOHC is still getting around ok but the tranny is acting up and I think its getting to be time to do both.
Thank you,
Will
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Old 07-04-2008, 07:59 AM   #15
armigerlives
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I would recommend just replacing your tranny with the same model, unless you are running a FWD and want to change to AWD. In the car I built (see above) I am using a 2000 SOHC 2.5 mated to a '93 FWD AUTO transmission. Your '95 tranny can take it. As far as the engine goes, any non-turbo 2.5 is a pretty easy swap. See above posts for info on the swap.
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Old 06-29-2016, 10:38 PM   #16
suzy95
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Quote:
Originally Posted by armigerlives View Post
Heya, I just did this swap last week, it took me 1 day. Your problem spots are going to be the fact that you need change the Injector plugs on the 1.8 harness to the ones from the 2.5. Also, the 2.5 ignitor is combined with the coil pack to you will need to jump wires 1 and5, and 2 and 6 on your curent ignitor plug. Disregard the ignotor because you will be using the one in the 2.5 coil pack. You then replace the 1.8 coil pack plug with the 2.5 plug. Allow yourself xtra wire as it is always helpful in case you have to redo it for some reason. The 2.5 plug has an xtra wire, namely the ground, take this and just ground it by close to the coil pack, all the other wires are the same from the 1.8. Those were the biggest problems I had. BTW, if you have an auto you may need to use to old flex plate because the newer ones are bigger and will not match your trans. The Temp guage is also one you will need to change the plug on. On the 2.5 harness it is a triangular plug, on the 1.8 it is 2 separate plugs. What you do is wire the 2 wire plug into the top 2 wires of the triangular plug, the single wire plug then gets wired into the bottom wire on the triangular plug. any problems you have post them and I will try and help. Sorry if my descriptivness isn't very good.
When you say jump wire do you mean put them together? Also the coil plug on the 2.5. How dou you know which is the extra ground wire ? I'm in the middle of wiring now and I don't know what to do with the coil wires any help would be nice
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