Ignition problem

Stim, Thanks for that information. Took the switch to a mechanic and he checked it. Suggested I replace which I did ($37.00). Seems to work fine now. Arnold

Normally a diesel engine has a solenoid for shut off.
When you turn the key on it causes the solenoid to open letting fuel to the pump.
You might have had a sticking solenoid. ???
Years ago I had a CAT engine in a Boom Truck. Once warmed up if I shut it off for any length of time the pressure would build up and it would not re-start until cooled down or I opened a fuel line and drained pressure on the solenoid.
I learned to shut it off then turn key back on if I was going back out with the truck.
At the time I was too broke to replace the solenoid!

Thanks for the input. PROBLEM SOLVED. I think the battery was too low to send energy to the switch telling whatever to shut down the engine. Having run about an hour may have charged up the batteries enough for that message to be sent with a command to shut down. Anyway I pulled the guts out of the ignition switch (1999 chevy truck) and put a screwdriver inside and turned the switch off. Stopped. Now I had tried that earlier but it didn't work which makes me think the batteries were too low to send the correct command"

Never got to the helpful ideas you sent but that was my next move. I'm sure one of those ideas would have worked.. This forum has provided me with a lot of help and I am thankful to you members for that. Arnold

check if there is a wire with a fuse attached to the positive post of the starting battery set, sometimes there are two fuses one for the transmission and one for the engine, if they are marked pull the one for the engine if not marked pull them both, the engine should die. if no fuses remove the positive battery cable.

Identify the injection pump and pull the wire going to it.
If that doesn't do it, stuff a blanket in the intake on the dirty side of the air filter to choke it off.

My CAT has an "Emergency Stop" button in the engine bay that shut downs the engine. It's big and RED and you can't miss it. Maybe you can disconnect the chassis battery. May also need to disconnect the house based on how the charge circuit is set up.