car wont start possible wiring problem

currently:
90 civic (d15) with MPFI thats F@CK"D to $#!+'s (as far as the wiring harness goes). OK so it has a 10 ecu code (IAT sensor) i stiill havn't been able to locate it or what the wires look like(color specs). My friend and I ripped the tach off (due to possible battery dranage) we jump/started the car and ran it for a while to get a feel of it. Then we got stupid and pulled the ebrake in 2nd gear and powerslid to a sputered halt. Diagnosis is the ignition wire was off then we tried to restart the car but it didnt work; we tried a jump start and that didnt work either. emergancy lights work but nothing else electrical lights up (signals, highbeams, dash, Nothing not even a beeping noise) some times when we lift the hood a plug near the resistor box is unplugged but we replug it
Here are my Q's:
1. what fuse or sensor or wire is causing the civic not to crank?
2. what are the colors for the ef9 si iat sensor?
3. what is the plug that keeps slipping off near the resistor box?
4. There are 3 plugs that have no connection whats so ever neat the T/b and Manifold
5.does any one have a spare si harness up for grabs?
6. can it be the alternator or something ? please add ideas to trouble shoot the problem.
:smokin: :screwy:

well thanks for the help fellas !! lol
BTW i should get some pics of all the stupid sh@t thats wrong with the car so be ready for updates.