I am attempting to get a 1994 caravan with a 3.3 to run. The ECM , crank sensor , and coil pack have all been replaced with new pieces. Battery is good , it is getting fuel , but no spark. I am getting no codes at all except start and end of test. Any ideas ?

On the 3.3L engine, Spark is controlled by both the crankshaft sensor and a camshaft position sensor.
The camshaft sensor is found at:
UNDER HOOD, PASSENGER SIDE, LOWER ENGINE AREA, BELOW WATER PUMP, ABOVE CRANKSHAFT PULLEY, MOUNTED ON TIMING COVER