Land Rover Repair: 1997 land rover discovery no spark, land rover discovery, crankshaft position sensor

Question
I have a 1997 land rover discovery se. I just recently took it to a shop and had the motor replaced. I started and drove but ran a little rough for the first day or two then would only start by chance every once in a while. We checked for spark and most of the time there was none but sometimes randomly it would get spark. I drove the vehicle one night when it was raining and it stalled out on me and hasn't started since. I decided to change the crankshaft position sensor  after reading some blogs on here, unfortunately it did nothing , but the wires to the plug for the sensor had some bear spots but my friend who is a mechanic told me that shouldn't stop the vehicle from firing. I checked all fuses and all easily accessible ground wires. Also i changed the plugs and wires, the ground wire for the battery and the ignition switch, no luck. The vehicle turns over fine but with no spark can't start. when the mechanic brought it back he installed the coil pack from the used motor i bought and not the original one from the truck. I am told that maybe I lost my drive authorization or something but i can't afford to take it to a land rover shop as it won't start and the nearest land rover repair shop is over 100 miles from where i live. Could you please give me some suggestions

Answer
Hi Nathaniel,

could be the coil pack itself. Can you replace it with the original from your old engine?  

How about fuel being present with spark?

If its the ECU you won't get spark or fuel.  IF so, you'll need the help of the LR dealer to reprogram or test ECU.

Best of luck,

JohnMc