Beating A Dead Horse, 03 USDM WRX + 2004 2.5L STI + JDM V7 ECU

[OC_Nooby]

I was searching around, got some conflicting information. So I'm making a thread. I think I got the right idea.

I have the following:

2003 WRX USDM (all harnesses WRX)
STI 2.5L (AVCS not running), controlled by the WRX ECU

Can I get a v7 STI ECU and plug it directly to my 03 WRX USDM ECU connector? Then get the IAP AVCS wiring kit and hook it up to its designated location in the ECU connector?

All my sensors will work, no rewiring? I read something about the temp sensor not working (did JDM Subaru's have a separate one other then the one located in the MAF)?

Thanks!

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[yellowbus]

Im acutally stuck on the same issue. A friend of
Mines told me that the jdm ecus will plug in and avcs will need to be wired or plug in via the plug in play wirings.

[OC_Nooby]

anyone can confirm?

[lukeskywrx]

You need JDM cam sensors, JDM cams and you need to add the front cam sensor that sits above the drivers intake cam gear on the 16 bit ecu motors. You will have to machine the heads a bit to get the JDM sensors to sit right and pickup off the JDM cams.

The JDM ecu plugs right in and you just add the AVCS, intake temp sensor will work just fine the ECU uses the one in the MAF. Later models V8-V9 have a sensor in the manifold but it is not used by the stock ECU, most believe it comes into play when the cars are setup for group N rally.

A local guy did this exact swap so I know it can be done, and everything works.

[OC_Nooby]

There is a difference between the JDM cam sensor and the WRX cam sensor? I have the cam sensor on the STI motor in the same location as it was on the WRX motor. Also why do I need JDM cams? My STI cams are AVCS capable.

Thanks!

[lukeskywrx]

Originally Posted by OC_Nooby

There is a difference between the JDM cam sensor and the WRX cam sensor? I have the cam sensor on the STI motor in the same location as it was on the WRX motor. Also why do I need JDM cams? My STI cams are AVCS capable.

Thanks!

By cam sensor I am referring to the sensor on the back of each head that reads the rear of the cam for AVCS position. JDM cam sensors are hall effect the USDM ones are optical, Each sensor can only work with its matching cam. The JDM ecu can only use the signal from the hall effect sensors.

So simply put you must match cams, AVCS cam sensors and ECU. In addition you must add the front cam gear sensor, but it sounds like you already took care of that.

[OC_Nooby]

Well my motor has those rear cam sensor. Can I use those? They are the stock ones that came with my sti motor.

[lukeskywrx]

Originally Posted by OC_Nooby

Well my motor has those rear cam sensor. Can I use those? They are the stock ones that came with my sti motor.

Not with the JDM ECU, I dont know how I can make this more clear. The JDM ECU cannot read the USDM sensors and vice versa. The JDM sensors cannot pickup the USDM cams and vise versa.

JDM ECU + JDM Cams + JDM AVCS Sensors = Working AVCS

USDM ECU + USDM Cams + USDM AVCS Sensors = Working AVCS

JDM ECU + USDM Cams + USDM AVCS Sensors = NO AVCS

USDM ECU + JDM Cams + JDM AVCS Sensors = NO AVCS

JDM AVCS sensors ≠ USDM AVCS Sensors
JDM Cams ≠ USDM Cams

[OC_Nooby]

ok that's clear, and slightly shattered my dreams.

[lukeskywrx]

Get a set of JDM cams with sensors and you are in business

[OC_Nooby]

Eventually, thanks for clearing it up!