1996 Land Rover Discovery

Engine Mechanical problem
1996 Land Rover Discovery V8 All Wheel Drive Automatic 120000 miles

have by-passed the starter to manually start the car because it wouldnt turn over or start with the key. Car turns over but wont start when by-passed and turned over manually. Have changed the crank sensor and checked ignition which is working properly. Ive tried to locate the diagnostic plug without any luck to see if I could get the diagnostic tool to tell me anything. It was having previous problems not starting but when put in neutral and back into park it seemed to fix the problem. Now nothing, if there is any ideas you can give me on maybe solving this problem I would greatly appreciate it.
January 16, 2010.

Check and test the neutral safety switch, also jumper the wiring connector and see if it cranks over

Jan 16, 2010.