well still no go. I replaced the SOV but it still won't start. I was able to reduce the bubbles by ensuring the return line was full of fuel, I replaced it and I think it was sucking the air from the line when I stopped cranking. Now that it is full of diesel the bubbles have significantly reduced. I do get black out the exhaust while cranking... Is this a good sign. I have four glow plugs out and it is getting colder here, perhaps that's the problem now. I have plugged in the block heater but maybe its not hot enough to make a difference.