Ccroak

Yeah I know, buy a wiring specialties harness it will save me a headache. I'm weeks deep into this now so I feel like I need to tackle this.

1999 SR20DE w/ 5spd into 89 auto s13 shell that i had a manual dual cam in previously.

I have followed a few diagrams and writeups to complete this swap. The running of a few wires to the dash plug, and to the grey and red plugs up front behind passenger side headlight.

My issue is that my ECU is not making my pin 4 black/red to go ground to complete and click the ECM relay.

This is the s15 power supply diagram. You can see pin 4 going to 2 on the relay. with positive power on one side and the ground trigger from the ecu it pulls the other two closed and completes the circuits. Without the switched ground from the ECU the positive from pin 1 on the relay flows through freely.



These are all my voltage readings I took on every single ECU pin whilst everything connected and plugged in, along with the wires I have spliced in and to what.



Also here's an s15 sr ecu pinout for a little more understanding.


I have done a lot of forum hopping so pls don't say use the search bar my problem is differing from others'.

My question is what is making my ECU think that is should not switch pin 4 to ground power?

I have jumped the black/red pin 2 on the relay straight to ground and it clicks the relay and my car will start and run. I'd like to avoid running a switch to that which is why I'm trying to evaluate why it won't do it on it's own like it's supposed to.

Also yes my relay is good, it's brand new and I tested it

saintjimmy333

Off topic, but does s15 sr20de tranny have a speed sensor? If not how’d you get the speedo to work


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Krusty_s13

5spd has a sensor on the trans.


Dumb question, but have you opened up the ECM and checked the condition of the board and the traces leading to that pin?

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