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Old 12-06-2020, 04:03 PM   #1
lucaduke
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Default 02 Wrx V7 Ej207 Swap Ecu Question

I'm planning on swapping a v7 207 into my 02 wagon. The engine in question would come with the ECU. My question is, and pardon my lack of knowledge, would I need to swap the whole wiring harness to get the engine running correctly? Or is it as simple as drop the engine in, plug the engine harness into the existing wiring harness, and just swap the ECU? Thanks in advance
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Old 12-06-2020, 05:18 PM   #2
Fierysun
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Old 12-06-2020, 05:22 PM   #3
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You have some options on how you can set it up. You can use the USDM ECU but you won't have AVCS. The JDM ECU will allow you to use AVCS you just need to wire it in. You can buy a kit from either iA Tuning or iWire to do it the easy way or you can get the wiring diagram and wire it in yourself. Either way is fairly easy. It if you aren't comfortable following a wiring diagram then buy one of the kits so that it's mostly plug and play. Either way, you don't need to swap wiring harnesses. The engine will have the engine harness on it. All you have to do is plug everything in.

Depending on what state you live in you may need to keep the USDM ECU for inspection/emissions purposes. I have to for my state and just swap the USDM ECU in once a year to get the inspection done.
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Old 12-06-2020, 07:05 PM   #4
lucaduke
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Quote:
Originally Posted by snow_bound26 View Post
You have some options on how you can set it up. You can use the USDM ECU but you won't have AVCS. The JDM ECU will allow you to use AVCS you just need to wire it in. You can buy a kit from either iA Tuning or iWire to do it the easy way or you can get the wiring diagram and wire it in yourself. Either way is fairly easy. It if you aren't comfortable following a wiring diagram then buy one of the kits so that it's mostly plug and play. Either way, you don't need to swap wiring harnesses. The engine will have the engine harness on it. All you have to do is plug everything in.

Depending on what state you live in you may need to keep the USDM ECU for inspection/emissions purposes. I have to for my state and just swap the USDM ECU in once a year to get the inspection done.


Thanks for the info! So I could plug and play the 207 if I use the JDM ECU in conjunction with one of the kits is what I got from that. And if I needed to pass inspection, I just unplug the kit, swap the ecu, and the motor should still run correctly?
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Old 12-06-2020, 07:09 PM   #5
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Yes.!
Quote:
Originally Posted by lucaduke View Post
Thanks for the info! So I could plug and play the 207 if I use the JDM ECU in conjunction with one of the kits is what I got from that. And if I needed to pass inspection, I just unplug the kit, swap the ecu, and the motor should still run correctly?
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Old 12-06-2020, 07:21 PM   #6
lucaduke
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Originally Posted by murrdogg24 View Post
Yes.!


The only issue is that the prior ECU was stage 2 tuned for an ej25. Would it be easier to just buy a stock USDM ECU or try to detune that one?
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Old 12-06-2020, 08:31 PM   #7
murrdogg24
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if you know how to use ecuflash and romraider you could flash a stock rom back to the usdm ecu...try checking out the romraider forums
Quote:
Originally Posted by lucaduke View Post
The only issue is that the prior ECU was stage 2 tuned for an ej25. Would it be easier to just buy a stock USDM ECU or try to detune that one?
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Old 12-06-2020, 08:44 PM   #8
lucaduke
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So Iíve been reading this thread

https://forums.nasioc.com/forums/sho....php?t=2285827

and itís got me confused.
They claim that if you have a USDM car, with the USDM wiring harness in the car, it is plug and play with the JDM ECU, no extraneous wiring or anything necessary. But others say you need the IA Tuning kit to wire in extra plugs for AVCS. But others say that as long as you just have the JDM ECU you get working AVCS without the IA Tuning kit???

Anyone know whats right?
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Old 12-06-2020, 08:47 PM   #9
murrdogg24
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There is 4 missing wires on the USDM cars that you need for AVCS, like the other have stated, you can 1)buy a wiring kit 2)make your own wiring 3)not install the wiring and not have AVCS. I can tell you from experience having AVCS makes a huge difference turbo spool especially on the twin scroll turbos.

Quote:
Originally Posted by lucaduke View Post
So Iíve been reading this thread

https://forums.nasioc.com/forums/sho....php?t=2285827

and itís got me confused.
They claim that if you have a USDM car, with the USDM wiring harness in the car, it is plug and play with the JDM ECU, no extraneous wiring or anything necessary. But others say you need the IA Tuning kit to wire in extra plugs for AVCS. But others say that as long as you just have the JDM ECU you get working AVCS without the IA Tuning kit???

Anyone know whats right?
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Old 12-06-2020, 09:04 PM   #10
snow_bound26
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Default 02 Wrx V7 Ej207 Swap Ecu Question

Quote:
Originally Posted by lucaduke View Post
So Iíve been reading this thread

https://forums.nasioc.com/forums/sho....php?t=2285827

and itís got me confused.
They claim that if you have a USDM car, with the USDM wiring harness in the car, it is plug and play with the JDM ECU, no extraneous wiring or anything necessary. But others say you need the IA Tuning kit to wire in extra plugs for AVCS. But others say that as long as you just have the JDM ECU you get working AVCS without the IA Tuning kit???

Anyone know whats right?


To use AVCS you need the JDM ECU and proper wiring. If done yourself it requires adding 4 wires plus a shield wired rom the ECU to the grey plug on the passenger side strut tower, re-pinning 4 wires on the ECU and re-pinning 4 wires on the black plug between the fuse box and battery. This allows you to repurpose the TGV wires to the AVCS.

If you use a pre-made wiring kit, then it adds the wires you need to the engine harness and ECU without repurposing the TGV wires.

AVCS will not work without adding in the proper wiring and ECU. Plain and simple.

As for passing inspection and emissions, that depends on what state you live in. CA for instance, is going to be more of a process. But if you're fortunate enough to live in a state that just looks for readiness codes, then all you have to do is swap ECUs. No need to unplug the AVCS as the USDM ECU won't control it anyway. The important thing here is to make sure you have a proper tune to run the engine. Your tuner can take care of this and should know the ins and outs of one of these swaps. So if you haven't found a reputable tuner yet, then that's your next task and the most important thing to do at this point in the swap.

Last edited by snow_bound26; 12-06-2020 at 09:09 PM.
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Old 12-06-2020, 09:25 PM   #11
lucaduke
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Quote:
Originally Posted by snow_bound26 View Post
To use AVCS you need the JDM ECU and proper wiring. If done yourself it requires adding 4 wires plus a shield wired rom the ECU to the grey plug on the passenger side strut tower, re-pinning 4 wires on the ECU and re-pinning 4 wires on the black plug between the fuse box and battery. This allows you to repurpose the TGV wires to the AVCS.

If you use a pre-made wiring kit, then it adds the wires you need to the engine harness and ECU without repurposing the TGV wires.

AVCS will not work without adding in the proper wiring and ECU. Plain and simple.

As for passing inspection and emissions, that depends on what state you live in. CA for instance, is going to be more of a process. But if you're fortunate enough to live in a state that just looks for readiness codes, then all you have to do is swap ECUs. No need to unplug the AVCS as the USDM ECU won't control it anyway. The important thing here is to make sure you have a proper tune to run the engine. Your tuner can take care of this and should know the ins and outs of one of these swaps. So if you haven't found a reputable tuner yet, then that's your next task and the most important thing to do at this point in the swap.


Quote:
Originally Posted by murrdogg24 View Post
There is 4 missing wires on the USDM cars that you need for AVCS, like the other have stated, you can 1)buy a wiring kit 2)make your own wiring 3)not install the wiring and not have AVCS. I can tell you from experience having AVCS makes a huge difference turbo spool especially on the twin scroll turbos.


Thank you both for the information! I think I know what to do now. Appreciate all the replies.
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Old 12-07-2020, 06:21 PM   #12
Bluebieru
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Quote:
Originally Posted by snow_bound26 View Post
You have some options on how you can set it up. You can use the USDM ECU but you won't have AVCS. The JDM ECU will allow you to use AVCS you just need to wire it in. You can buy a kit from either iA Tuning or iWire to do it the easy way or you can get the wiring diagram and wire it in yourself. Either way is fairly easy. It if you aren't comfortable following a wiring diagram then buy one of the kits so that it's mostly plug and play. Either way, you don't need to swap wiring harnesses. The engine will have the engine harness on it. All you have to do is plug everything in.

Depending on what state you live in you may need to keep the USDM ECU for inspection/emissions purposes. I have to for my state and just swap the USDM ECU in once a year to get the inspection done.
How would he be able to swap in a usdm ecu to pass inspections? Doesnt the usdm ecu need a signal from a usdm crank sprocket and cam sprocket to even start?
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Old 12-07-2020, 07:57 PM   #13
snow_bound26
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Quote:
Originally Posted by Bluebieru View Post
How would he be able to swap in a usdm ecu to pass inspections? Doesnt the usdm ecu need a signal from a usdm crank sprocket and cam sprocket to even start?


That's only an issue with 32bit ECUs. The 16bit ECU is just unplug and swap the other in. Having it tuned for injectors, airflow, etc is all that's needed. I have a very basic tune on my USDM ECU so it runs smooth and I can drive it to and from the shop.
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