Check Engine Light takes to turn Jeep GC Ltd

I have copied this explanation from another post on another page but it is exactly what happens to me, I hope to find here the solution to this problem.
My car is a Jeep GC Ltd 1994 Allwheel Drive with 4.0 lts engine.

This started about 6 months ago, one day the light of Check Engine turned on but the car started well and worked well without problems, after a week I had to have the key open for approximately 10 minutes for the light of check Engine appearing and listening that the gasoline pump was activated and then could start, this time it lengthened until almost half an hour so much so that I decided to leave the switch with the key with the key with the key in the light In order to use the car, this served for a week and now simply the light of Check Engine does not turn on or the pump is heard even if it left it connected for a whole day, I want to clarify that when it started it worked perfectly and could stop it and start it at the time without any problem but if it stopped it more than 15 minutes it had to wait until half an hour to start, I need help.

Little can I tell you, more than if it has a relief (or revealing) for the gasoline pump, etc ..., to look at it if this fails, to begin to look at things ... it seems that I will not reach the ECU ... to see also if it is from the contactor of the key itself, that it is spent. 20 years old is

If in reality it does not have much logic because the contact opening time is not influenced by the opening time but could go through a detail in the state of the same gasoline pump, I check fuses and relays first, then and depending on the stat Pump the bad or problems with the injectors, you will have to disassemble them try them and clean them, EYE Try them not only the Liempies that always happen that they clean them and do not know how they work. Good luck and let us know.

Thank you for answering my message, I tell you that all those tests that you suggest to me and I have done them and all the components are fine, as I said, if at this moment I go to the car and I leave the key in Run for about 20 or 30 minutes the light of Check Engine turns on and the engine starts normally and I can turn it off and light it as many times It takes. I would like a connection diagram of the ECU to see and checkear the dots of earth or ground to see if they are correct.
Thank you.