For those that are familar with the PowerFC installtion, the four wires we cut are as follows. (Written by Dale Clark)

1. EGR Solenoid output (4O)
2. AWS Solenoid output (4P)
3. Split air Bypass solenoid valve (4F)
4. EGR Switch input (3J)

"These 4 wires are for extra emissions devices that were added in the US market, but weren't in the Japanese market" "The only reason for this modification is making US wiring harness similar to Japanese harnesses."

Given these modifications, it appears that a fifth wire, the Solenoid Valve Relief 2 (3K), should also be cut. JDM models do not include certain components like the EGR and AWS, which is why we've already cut wires for the EGR Solenoid, EGR Switch, and AWS Solenoid. This brings us to the ACV configuration in USDM models, which consists of three valves and two actuators: the Split Air Bypass, Port Air Bypass, and Relief 2, along with actuators for Switching and Relief. It's important not to confuse the Relief actuator with the Relief 2 solenoid valve. We've already cut the wire for the Split Air Bypass Solenoid Valve (4F). So, why do we keep the Relief 2 solenoid valve (3K) when it isn't present in JDM ACVs, meaning the pinout is not present in the PowerFC?


Ignore the red (only image available)


USDM ACV, featuring three solenoid valves and two actuators.


JDM ACV, only the Port Air Bypass solenoid valve is present. The area circled in the image indicates where the Split Air Bypass solenoid valve would typically be installed, but note that this spot is cast over, preventing installation.


The area circled in the image indicates where the Relief 2 solenoid valve would typically be installed, but note that this spot is cast over, preventing installation.

This leads us back to the original question: if our goal is to align the USDM harness with the Japanese harness, why aren’t we cutting the Relief 2 solenoid valve (3K) just as we are cutting the Split Air Bypass solenoid valve (4F)? Additionally, if we kept the four wires (or five) connected, would they connect to an unused pin on the PowerFC? Do we even need to cut these wires? I'm also in search of a pinout for the 1992-1995 JDM ECUs to compare with the USDM ECU pinout I have above. Unfortunately, I can’t find a high-quality JDM pinout for a proper comparison. Does anyone have access to this information?

 

Additionally, if we can confirm that the PowerFC does not utilize the Relief 2 solenoid valve, (which I doubt it does) then purchasing the JDM ACV is a viable option.

 

couple of links, JDM ACV works fine. those solenoids let Mazda have a little finer control over where the air pump air goes, but its not really important, and the PFC doesn't care
you will also see that the HVAC pins are a lot different, the JDM FD is closer to the S5 FC in this area. the US FD runs out of pins so they have to add the e/l box which lets them use the couple pins for multiple things

https://www.rx7club.com/3rd-generati...-fd3s-1151771/
https://www.rx7club.com/power-fc-for...inouts-615909/

 

Hmm.... Would clipping this wire cause issues in Cali where we swap to the stock ECU for emissions testing?

 

I took the recommended pins out at the PFC while leaving the harness untouched, that way there won't be any issues if I ever change ECUs

 

It might or might not cause issues, here’s a picture of what each component controls, maybe someone can give further details.

 

You should remove the pins, not cut any wires.