Dont know what else to tell you, I'm not a diesel mechanic, but troubleshooting is my profession. I can't really see anything that looks out of place. Sorry!

I found something about a fuel collar that causes runaway on a early Cummins, but the link wouldnt paste. It was on the Cummins forum.

Runaway, what is it, how do I stop it?! - Dodge Cummins Diesel Forum
Finally got it to copy.

THANKS HILLBILLY1 FOR ALL THE PEOPLE HERE OVER 400 LOOKED AT MY PROBLEM. BUT YOU TRIED WHERE THEY DID NOT. AND I STILL HAVE NO IDEA WHAT TO DO TO FIX IT. BUT YOU HELP NEVER THE LESS THANK YOU