Working on this car for a neighbor.

Said he was driving and the belt popped off his car and the car stalled. Had the belt replaced and the car hasn't started since.

He has some aftermarket Anti-Theft piece that comes with a key card and the key card must be placed into the piece inside the interior in order for the car to start. Even with this key piece in the piece inside of the car, the car still doesn't fire up but it cranks. I believe if you don't have the key card it doesn't even crank.

He has 40 psi from the fuel pump when the key turn they key in the on position. He has fuel.

I bought a brand new spark plug and removed one spark plug wire at a time and put the new spark plug in the wire and grounded it to the engine and had the motor cranked over. All six wires gave spark to the spark plug. He has spark.

Haven't done a compression test yet.

Somebody said to check the crankshaft position sensor, could that cause a crank and no start issue ?