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USDM J30A5 to JDM J30A swap

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Old 02-27-2017, 06:40 AM
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Default USDM J30A5 to JDM J30A swap

Trying to help my uncle out. Recently swapped out a blown USDM J30A5 motor (2006 Accord) with a JDM J30A motor. The issue he's having include:

Vtec wiring from USDM engine harness to JDM Vtec solenoid.
Knock sensor location (different location and different wiring).

He's searched and I've spent about an hour searching but can't find any data on wiring / splicing or compatibility.

Any help would be appreciated. Thanks.
Old 02-27-2017, 10:29 AM
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Default Re: USDM J30A5 to JDM J30A swap

Can't you just swap the knock sensor and vtec solenoid from the old engine to the new one?
Old 02-27-2017, 10:58 AM
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Default Re: USDM J30A5 to JDM J30A swap

Different location- different sensors so it's not swappable.
Old 04-26-2018, 06:58 PM
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Default Re: USDM J30A5 to JDM J30A swap

How you guys doin. Question, did you ever figure or get this situated. I just picked up a jdm j30a and got it installed and running good but im having the same issue you are. Any help? Thanks.
Old 07-18-2018, 09:25 AM
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Icon5 Re: USDM J30A5 to JDM J30A swap

Hello Sir did you find any way I have the same issue can you please help me out ?
Old 07-18-2018, 11:09 AM
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Default

This is what u do, cut blue wire on Solenoid plug end and tap in the wire in the black sleeve wire. I believe its a green wire inside the
For the Vtec wiring this is what u do..... check engine light will come right off
Let me know if this helps you guys or if u guys have anymore questions.

Last edited by toyomatt84; 07-18-2018 at 06:24 PM.
Old 01-22-2021, 06:53 PM
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Default Re: USDM J30A5 to JDM J30A swap

Do I need To put the old oil filter housing on the new engine for this to work?
Old 03-30-2021, 06:19 AM
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Default Re: USDM J30A5 to JDM J30A swap

Originally Posted by MostWanted805er
This is what u do, cut blue wire on Solenoid plug end and tap in the wire in the black sleeve wire. I believe its a green wire inside the
For the Vtec wiring this is what u do..... check engine light will come right off
Let me know if this helps you guys or if u guys have anymore questions.
I am do this swap this weekend on a 2003 Honda accord j30a4 to a jdm j30 your help is happyful

​​​​​​
Old 04-12-2021, 07:54 PM
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Default Re: USDM J30A5 to JDM J30A swap

Will vtec work and will it rev past 5k once this is done? I just bought a jdm j30a to replace my j30a5. I was told on another forum this won't work because jdm j30a has vcm not vtec.... I'm lost
Old 05-11-2021, 04:28 AM
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Default Re: USDM J30A5 to JDM J30A swap

Hi I just did that swap to a jdm j30 and that doesn't work? Can you fill me in on how do that should work??





Originally Posted by MostWanted805er
This is what u do, cut



blue wire on Solenoid plug end and tap in the wire in the black sleeve wire. I believe its a green wire inside the
For the Vtec wiring this is what u do..... check engine light will come right off
Let me know if this helps you guys or if u guys have anymore questions.
Old 05-11-2021, 06:21 AM
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Default Re: USDM J30A5 to JDM J30A swap

Originally Posted by Vab78888
Hi I just did that swap to a jdm j30 and that doesn't work? Can you fill me in on how do that should work??
VTEC has 3 wires:
VTEC solenoid
VTEC oil pressure sensor
Ground

Disconnect/cut the oil pressure sensor wire from the oil pressure sensor
Cut the ground wire (no longer needed, will not be hooked up)
Solder/tap the oil pressure sensor wire into the VTEC solenoid wire.

This is how mine is set up. I did the wiring at the ECU so it looks clean.
Old 07-27-2021, 02:17 PM
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Default Re: USDM J30A5 to JDM J30A swap

Originally Posted by Canadian_EF
VTEC has 3 wires:
VTEC solenoid
VTEC oil pressure sensor
Ground

Disconnect/cut the oil pressure sensor wire from the oil pressure sensor
Cut the ground wire (no longer needed, will not be hooked up)
Solder/tap the oil pressure sensor wire into the VTEC solenoid wire.

This is how mine is set up. I did the wiring at the ECU so it looks clean.
I just did a J30A swap and my check engine light and TCS came on. Seems like it goes into safe mode at 2500 rpm. Will running the wire allow my Vtec to kick in and problems go away?
Old 12-21-2021, 10:25 AM
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Default Re: USDM J30A5 to JDM J30A swap


I got tired of looking sideways at this image.
Old 01-03-2022, 05:02 AM
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Default Re: USDM J30A5 to JDM J30A swap

Originally Posted by shelleyvideo

I got tired of looking sideways at this image.
Did this work for anyone? I'm getting a p2647 code after swapping my j30a4 for a j30 and keeping my original heads. Engine will not rev past 5000rpm.
Old 01-27-2022, 02:15 PM
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Default Re: USDM J30A5 to JDM J30A swap

I have the exact same issue with P2647 on a J30A5 to J30 engine swap on my 2006 Accord. I am also wondering if this solution really works before I hack up my wiring. It looks like you are bypassing the VTEC pressure switch and tricking the ECM to read an "open" pressure switch state when the VTEC solenoid is energized by the VCM. Is that right? I am not exactly sure how the VTEC control logic works, but this would mean that the VTEC pressure switch is supposed to open (i.e. sense high enough pressure) only when the VTEC solenoid is energized on. Is that right? With the solenoid deenergized, it seems like the ECM would sense about 15 ohms from the solenoid coil instead of zero for the closed pressure switch. Is that low enough to keep the ECM from throwing P2647 for an open circuit? My last question is what happens now if oil pressure is indeed too low to operate the VTEC system when the VTEC solenoid turns on? Will damage occur?
Old 02-01-2022, 02:34 PM
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Default Re: USDM J30A5 to JDM J30A swap

BTW, this solution did work for me. I made the chaange at the ECM as a previous responder suggested. VTEC feature work just fine. Revved up to 6k no problem and no code
Old 02-04-2022, 09:57 PM
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Default Re: USDM J30A5 to JDM J30A swap

Originally Posted by Vab78888
Hi I just did that swap to a jdm j30 and that doesn't work? Can you fill me in on how do that should work??
How do you know which wire is ground in case the wire colors are different?
Old 02-04-2022, 10:00 PM
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Default Re: USDM J30A5 to JDM J30A swap

Originally Posted by mahoneytim
BTW, this solution did work for me. I made the chaange at the ECM as a previous responder suggested. VTEC feature work just fine. Revved up to 6k no problem and no code
How did you do it at the ECM, I do not have a wiring diagram?
Old 02-06-2022, 08:33 AM
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Default Re: USDM J30A5 to JDM J30A swap

You need to locate and pull connector E from the ECM. It is white and is located closest to the front of the vehicle. You can access this connector easily by removing the console panel on the right side (it has just one fastener) and then pulling the carpeting back a bit.
Looking at Connector E from the back (i.e. the side with the wires sticking out), pin 22 is the VTEC solenoid wire (GRN/YEL). Pin 23 is the VTEC Pressure switch wire (BLU/BLK). Do not confuse these with pins 30 and 31 injector drive wires which are BLU and RED. You snip wire #23 and take the loose wire end from the connector side and splice it with wire #22. You don't need to worry about the ground wire from the VTEC pressure switch. The ground wire runs from the switch to a chassis ground and does not connect to the ECM. It stays in place with no function anymore. I hope this helps.
If you want to figure out how this workaround works, look at my Post #15.

Connecter E at the ECM is white. It is the one that is closest to the front of the vehicle
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Old 03-24-2022, 08:01 PM
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Default Re: USDM J30A5 to JDM J30A swap

I believe on mine we wired the old vtec solenoid up but just have it mounted randomly in the the engine bay. Mechanically it does nothing but the ecu thinks it does. Revs out fine w/ no ced. 07 6 6 sedan
Old 09-26-2022, 08:36 PM
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Default Re: USDM J30A5 to JDM J30A swap

hello please help. Just purchased an 04 accord coupe 6-6 and of course I didn’t look at the motor stamp or really give it a good enough drive cause it was so cheap. Turns out it is a j30a swap. So unlike everyone else I’m not having any codes seems like they did what everyone is saying. But here’s where my problems start or maybe it’s normal. I sometimes have great power and sometimes it seems like I’m not getting the power I should get. I had to remove tcs fuse and tc system fuse to get my tires to chirp and I also had to remove the butterfly as I am thinking the AFR is out of wack. Anyone had these same issues?
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