Fuel filter/plastic lines/o-rings/new screen all changed. Was only run on the bio-diesel for about 1/2 tank. Have literally taken the injector lines off of the injectors while cranking and am getting nothing but am getting good flow to the pump.
It was running fine. He drove it all the way from CA to MI (filled up with the bio in Chicago). Drove it around the Detroit area for a few days and then went to leave after a lunch and it wouldn't start. So whatever happened it happened suddenly.
I had been puzzled as to how a mechanical system could all of the sudden just stop working and the relay that also shuts the "throttle" to zero if it fails sorta fits the bill. I'm not ruling out that crud got into the injector pump but to fail all of the injectors at once doesn't sound right and the suddenness of it doesn't sound right. It seems that if it was crud it would hit one or two of the lines and be sluggish first and then maybe not start.

That being said, getting a new relay is cheap and easy to try before we go digging into the pump.