DC Power Loss

Let me start from the beginning. I bought a 96 Cherokee with the 4.0 High output. Was wrecked in front, but had a good motor.
I also bought a 91 Cherokee, is was supposed to have had a bad motor. The man I bought it from said that it just quit running, and thought the engine jumped time. I pulled the motor from the 96 Cherokee (ran great when in the donor truck) and did an engine swap in the 91.
1. I replaced the engine harness with a donor form the junk yard.
2. I replaced the battery (new).
3. I replaced the alternator with a new one (don't ask).
Everything is hooked up the way that it is supposed to be, but no start.
When you turn the switch on, you have power for about two seconds to the coil, fuel pump relay, and emergency shut down relay, then nothing.
Turn the switch off and back on, the same thing, power for about 2 seconds then nothing.
What could I have missed ??
Thanks for any help.

Are you using the computer from the 91 or the 96? Just wondering if the 91 quit because of that?

I'm using the computer off the 91. The 96 won't work. The harness is completely different.
I pulled the harness tubing back form where it plugs in to the computer. I found the gray wire is broke in two. Someone has tried to solder it in the past. According to the schematic, it goes to the coil. I am going to repair the wire tomorrow and see if that makes for a miracle cure.