I have same problem with my 1990 L200 4d56 non-turbo, non-electronic.
Problem was getting worse, like this:
After letting it sit overnight, you let it glow the plugs, crank it and it feels like if the injection pump is without fuel, it started, then died inmediately.
Then if before it died one runs and pumps the primer pump that goes on top of the fuel filter,it hessitated a bit (due to trapped air, I guess) but engine kept running and all was OK.
So, I replaced the primer pump, which comes with the fuel filter base, with a new one.Worked fine, for a couple of weeks, then it came back, when cold, it starts and then dies, like if it has no fuel or if the injection pump is empty.
Pumping manually didn't help any more, so I installed an electric fuelp pump (low pressure, like the ones for older, carburated gas engines) right in the feed line, near the fuel tank, to make the filter and injection fill up with fuel while the glow plugs are running (electric pump was connected to the glow plug relay to achieve this).This helped a bit, but cold start take 2 or 3 tries, after which the engine hessitates, misfires, sounds like not all cylinders are getting fuel,puffs white smoke for a while, and then stabilizes.I even connected the AC compensator(with a separated temp send unit) in a way that keeps the engine in high idle while coolants gets warm.
What can be wrong? I think that it is not the injection pump, since a have make sevrala trips well over 300~400 miles and the engine runs perfectly, it goes uphills, pedal to the metal on flat roads, and I don't even feel that the governor tries to cut-off.Smoke at tailpipe is normal at all times.
Please help! I don't want to start spending money on things like pump and injector calibration until I'm sure!