I have an 88 Crx SI. It had a cut wiring harness under the dash where the ECU goes.

so I replaced it with a 91 SI wiring harness. The engine harness is an 88 HF. When I try to start the car i hear a click from the main relay but nothing happens other than the high beam on the driver side head light turns on....

I connect a wire to the starter and It doesnt get spark. anyone know if pinout is different from the 2 wiring harnesses. THANKS!

 

HF and Si harnesses are not the same - you could re-pin the connectors and do some modifications and make it work: