You need to get a few crimp pins for that connector, and then you need to crimp them on the wires. Then insert the crimp pins into the connector shell. You can find someone with the right tools to do this for you, it's a very easy and fast job but without the right type crimpers you're going to do a horrible job.

You could also get a few wires from another OBD1 ECU harness and spice a few inches with the OEM crimp pin onto the wires you ran.