[denisond3]

My Saturns are a 95SL2, a 96 SL1 and I worked on my daughter's 98 SL2. If the security system is not hooked up, I suspect that could be a reason it wont crank over. I think the only things 'not-needed' for the engine to run would be the air bags, the radiator fan, the ABS stuff, the detonation sensor and the wipers. There might be a sensor/switch on the trans that is part of the neutral safety interlock, but I am not sure. Mine starts equally well in neutral or any gear, but the clutch pedal sure has to be pushed all the way down. That closes a switch that is a starter-safety interlock. The clutch release hydraulics working or being smashed would make no difference.

What would be vital for engine operation (as opposed to cranking the engine over) would be the" Throttle Position Sensor", Manifold Pressure Sensor, Crankshaft Position Sensor, Engine Coolant temperature Sensor, the harness and connectors to the injectors, possibly the oil pressure sensor, the vehicle speed sensor, and all of those little ground wires. If you didnt have the EGR connected up, the Check Engine Light would probably stay on, but the motor wont ever care.
You could run a wire from the 'small' terminal on the upper part of the solenoid mounted on top of the starter, and long enough so that you could touch the other end to the positive terminal on the battery. That way if you had the ignition on, and touched that wire to the battery "+", the starter would spin the engine - and it would be running. This also bypasses all of the safety interlocks, so it if were in gear the car would start moving instantly too; therefor be Super Careful. Also, keep the end of that wire from bumping into contact with anything else under the hood.
With our 98 SL2, the ignition key would not engage the starter consistently for a while. I wired up a pushbutton on the dash with my own wires to the starter solenoid and to the battery. My daughter drove the car that way for about a year. It would start with the igntion key only very rarely, but using the button it was 100% reliable.
Eventually I replaced all of the fuses in the box below the passenger side console, and two things resulted: The dome light now worked again, AND the car would now start with the ignition key.

I remember a poster a couple of years ago mentioned having to replace a relay in a circuit board somewhere under or behind the rear seat, for their car to agree to crank its starter over and fire up. It was part of the security system. I never went looking for the relay since I solved our problem with the pushbutton.
Im rebuilding a 95 SL2 right now, and recently bought a used copy of the Saturn 1995 service manuals. There are about 12 volumes in the set, and it makes up a stack 8.5" by 11" by 12 inches high. The one with the wiring diagrams in it is 1.5" thick! The set cost me $140, and will have paid for itself by the time I put the engine back into the car.