If you mean it "fires up" and
roars into life as you start it but dies THE SECOND you let go of the key, your Ballast resistor is "fried" and it needs replacing. This is usually on Fords in the form of a "special" wire to the POS terminal of COIL, unless someone has installed a Ceramic Type in the Loom.
If problem is more serious...................
We'll assume it's a Bosch type starter with attached Solenoid and your car is still NEG earth..............................
get a test lite or volt meter on to one of those 2 wires you mentioned while key is off, with NEG/EARTH cable/wire of testlite/voltmeter on NEG Battery Terminal, and a known good battery is fully connected and terminals clean & tight. There should be no lite or voltage there at either of "your" 2 wires. If there is, do not use it/them. Now turn on ignition to first click and look for red IG lite on dash. See if one of those wires is 12v alive or lites up the test lamp. If it does, put test lite/volt meter somewhere you can see it while you go to key and turn to "start"........lite /12v must remain strong and constant, even after you let go and key wants to come back to "IGN on" resting position. If none of the wires do the above, you need to search for one in engine bay that does.
In the meantime, to prove Ignition system works, "hotwire" the car by ignoring the whole system as she stands, and run a new wire with 2 aligator clips from POS of Battery to POS or IGN post of COIL. Make sure cars in neutral & H/Brake on. If wiring is good to starter, turn key to start. If no joy, use a second new wire with clips to bridge small terminal(small wire can stay if it's there) at Starter Solenoid to large heavy cable at S/solenoid, quickly removing this wire from LARGE Solenoid terminal, or both. This will stop the starter whether engine starts or not (as normal). If engine still wont start, yell out. If it's now running and want to stop it, remove NEW little wire "No 1" from POS of Battery. Any probs , yell out.
nb........NEVER let any live wire or 12 volt feed touch NEG or CB(contact breaker) side of COIL.....ever.
post edited by BEEVEE - 2016/12/24 22:56:23