Wow..this is an old thread.
Hello from Germany. I have a customer with a 1984 dually with only 52K on the clock. Cold Start, no problem. Warm Start...no start. My brother visited us for the first time since I have been here (2005), and the customer begged us to come by his job-site (Landscaper) because the truck would not start at the end of the day. (or when Hot). NO fuel leaks, and it starts every time when cold. Just will not start when it is already warm. I will advise them about the Chinese water bath to see if that helps. I forgot that I now have a phone that is more intelligent than I am, otherwise I would have clicked off a few pictures. One thing I found was that the vacuum line on the thingamajig on the TPS? had a rip in it at the connection. This is the line that GM ran from the vacuum pump. I have had a lot of experience with the GM diesels. Those folks should be tarred and feathered, sent out of town on a pole to be slowly roasted.
Cheese and rice. Taking a gas engine and turning it into a diesel? I remember finding head bolts laying next to the rockers....
All the best.