Grand Cherokee 93 Automatic

Hello everyone.
I have a 93 Cherokee that presents the following problem: I open the ignition key and the entire system is energized except the ignition circuit, I have to wait for 20 to 30 minutes to reach the current to the high coil and have a spark in the spark plugs. I have reviewed all the sensors and ground connections, change the mechanical box of the ignition that goes in the rudder cane and I have not had results, the Scanner says that there are no problems, what advise me?