[v8volvo]

If you unplug the wire from the temp sender on the back of the cylinder head (right below the sprocket that drives the rear timing belt for the injection pump), it will trick the glow system into thinking the engine is dead cold, and the glow plugs will come on. It sounds like your compression is low enough that it needs the glow in order to start, even when warm. Common situation with worn-out diesels.

You might eventually want to temporarily install a manual glow system (using a Ford starter relay and a pushbutton), so that the glow plugs can be turned on whenever you want them. That would help you out if this situation arose again. In the meantime, just applying power to the plugs should be enough to get you going again -- just wait a couple hours till its cool enough to light the plugs and start, or use the trick mentioned above. Much easier than trying to put oil in the cylinders, etc, and less risky... you can bend rods and break pistons and rings if you overdo it with the oil.