I'd also say stuck fuel injection pump, but you can test a couple of things to verify that.
If you put a fuel shutoff valve (or use a set of vise-grip style hose clamp) on the line before the lift pump or sediment bowl, that will shut off the fuel. If it continues to run-away or even run, you are getting oil into the chambers somehow (if it's turbo-charged, you could have a leak in your oil seals on the turbo).
If cutting off the fuel kills the engine, then your rings (and if you have it, turbo) are good. At that point, something is opening up the system wide open. Disconnect the control linkage that runs the injection pump. Make certain it is pulled back to idle position AT the pump. If it runs away, then your issue is with the pump, it's stuck wide open. If it idles, then the issue is with your controller.
Admittedly, I don't know how mechanical or electronic the control are on your motor, but the principles I described above work to isolate systems and that is what you need to do.
If you put a fuel shutoff valve (or use a set of vise-grip style hose clamp) on the line before the lift pump or sediment bowl, that will shut off the fuel. If it continues to run-away or even run, you are getting oil into the chambers somehow (if it's turbo-charged, you could have a leak in your oil seals on the turbo).
If cutting off the fuel kills the engine, then your rings (and if you have it, turbo) are good. At that point, something is opening up the system wide open. Disconnect the control linkage that runs the injection pump. Make certain it is pulled back to idle position AT the pump. If it runs away, then your issue is with the pump, it's stuck wide open. If it idles, then the issue is with your controller.
Admittedly, I don't know how mechanical or electronic the control are on your motor, but the principles I described above work to isolate systems and that is what you need to do.