Plugged Fuel Tank Screen? When you loosen the Cigar hose to check the fuel flow when you re-install it swap the positions of the Cigar Hose and the Fuel Inlet hose where the tubing comes off the fender well. That will bypass the Fuel Tank Screen.

Some had said you need to have 1/2 tank of Fuel.

If you drive the Car like that and your problem goes away you know the than screen is plugged.

If the valves in your Fuel Supply/Lift Pump are worn the Fuel in the hose can flow back to the fuel tank and it takes a long time to get it back up to the Fuel Injection Pump when you try to start.
If pumping a lot on the hand primer brings fuel up to the pump and you start that maybe the issue.

Another way to test is to get a separated container with diesel fuel and get on the hand primer pump and then try to start and see if it will draw fuel out of the container.

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84 300D, 82 Volvo 244Gl Diesel