The starting for five seconds is telling me that the system is working and then breaking down.

This is beginning to sound like bad plug wires. If it will start again for even the five seconds then a test from those days is to see if you can see the electrical pluses running down the wires.

This method is at least ninety years old. Back in the 60's we thought we were smart for knowing how to do this.

The method is to be in a dark garage, or on a dark night, and to raise the hood. Then you just look at the engine, which you will not be able to see because of the dark, while a helper starts the car. It only needs to run for a few seconds.

If the wires are totally shot you will see blue pluses of electricity running down the wires. They will move quickly, looking like a lot of very fast blue worms.

Yeah, I know this sounds crude but when you are a thousand miles from a repair shop you do what you must to figure out a problem.

I have seen this several times. I can't explain what you would be seeing but it is quite impressive to see. It is also a sure indication that you need new spark plug wires.

(And back then the wires were not always kept apart from each other like they are now. When the wires would wear you would get what was called 'crossfire' where a spark from one wire would jump to another and fire the wrong plug. Or ground out on the block.)

And if you are really hardcore you can just grab a plug wire and hold on. You will know in less than a second that you need new wires. And yes, I once saw someone do this since they could not get their shop dark enough.