This is a pretty tough swap.
I did a '93 EJ18 to '99 EJ25 swap in our rally car. I had to do exactally what you did - cut off the old plugs, solder the new ones on, and then rewire the bulkhead to engine wiring harness as well.
The major issue with this conversion is that all of the documentation to do the swap doesn't exist in one place. I had to comb through about 7 different resources, creating a wiring conversion chart for my swap. All told, it took about 15 hours of prep work, and about 25 hours to do the whole swap.
Once you get everything hooked up and ready, try turning it over. If it doesn't turn over, check these things (in order)
1. Fuel? Check the lines. Turn the key to on, do you hear the fuel pump prime? If not, check that wire on the ECU.
2. Spark? Simple here, stick a screwdriver in one of the sparkplug wires, and put near the coilpack. Turn key. If you're got spark, great! One of the problems I had was the coil pack was kinda flaky, and I had to cut the wires off and solder them directly to the terminals on the pack, since the plug was faulty.
3. Airflow? MAP/MAF. Check those signals.
4. Throttle cable hooked up?
If that doesn't work, then look at more basic stuff... is the ecu plugged in? Getting the correct voltage you expect at various sensors?
If you have any questions, please drop me a line. I'll gladly provide my conversion wiring diagrams if they would help... I don't know if they would or not, but you can see my method.
Last Ditch Racing