Can I use a usdm Gsr obd-1 wiring harness to convert to obd-1 and use the plugs and what not for vtec on my jdm gsr.

Cars a 91 crx dx

 

Use the harness that came from your car. Convert the DX harness to MPFI (do a search), and purchase and obd0-obd1 conversion harness from blown90hatch to make things more simple. You will not utilize the injector resistor box if you choose to run the obd1 injectors. You WILL use that gsr harness for plugs such as: The 2 distributor plugs, 4 injectors plugs (if using the obd1 injectors), vtec solenoid plug, oil pressure switch plug, 4 wire o2 plug, ect switch plug, knock sensor plug, and IAB plug for secondaries if you are retaining the gsr manifold. hth