RB25DET S14 wiring details....

[silviamadness]

To make a long disappointing story short, I finally started sorting out the last few bits of my RB25 S14 conversion, and I have run across a few wiring issues. Now, the harness was "professionally" converted by a well known shop years ago, and after seeing a few suspect splices, I decided to remove the harness and do a thorough inspection. To say the least, it was poorly done and needs some attention. I went through the whole harness and confirmed that all the necessary necessary terminals were connected to the F3 connector, and document all the circuits that were missing. The inspection revealed that the power source for the O2 sensor, AAC, and the VTCV was not connected. The power source for these components comes from the F3 connector (white connector near ECU), and should be a 12V switch source to the Blue/White wire in the harness. I chose to use pin 10 (Black/yellow) from the F3 connector, which solved my high idle issue. I also found that the Sky Blue wire which goes to the air regulator was not connected to a power source. Again, this gets a 12V switched power supply, which I received from pin 18 (Brown) on the F3 connector. From what I understand the air regulator only operates during cold start up, so making this connection made no noticeable change. Now the strange problems I found, came from the wiring of the IGN relay, and the ECCS relay. Based on the wiring diagram I used the ECCS relay gets a 12v CONSTANT power source to two terminals, and is spliced off to supply power to ECU pin 58. After inspection I found that there was no wire leading to the White/Black wires on the relay, however the engine would still start. Even with the ECCS relay removed the engine would still start. For those who are familiar with the wiring of the F3 connector to the relays, did you run a 12v permanents power source to the White/Black wires on the relay and pin 58 on the ECU?

[Darius]

Power is supplied to the ECCS and IGN relays via the F3 plug. If you google the "RB25DET wiring diagram", it shows the wiring configuration between the ECU, relays and F3 plug. Are you referencing the RB25 into S14 wiring guide?

[silviamadness]

Power is supplied to the ECCS and IGN relays via the F3 plug. If you google the "RB25DET wiring diagram", it shows the wiring configuration between the ECU, relays and F3 plug. Are you referencing the RB25 into S14 wiring guide?

Thanks Darius, everything looks to be sorted out, as I completely reconfigured the harness and now everything operates properly, and and is interfaced with the Nistune. The wiring was pretty straight forward, as there were only a few circuits used from the F3 connector aside from the wipers, and minor relay circuits. I think I am going to dissect the lower harness next, and go through as well. Thanks for the help Darius

[Darius]

No problem. It sucks having to sort through someone else's hack job. I even dig into some of my own handy-work and wonder WTF I was thinking 7 years ago. Keep us posted if you have any questions.