Could be you have a small Air Leak or the Valves inside of the Fuel Supply/Lift Pump are not sealing well and allowing some your Fuel Supply Pump to lose its prime.

Before you attempt to start get on the Hand Primer and pump about 25 times. See if you feel any differenced during the pumping or if the Hand Primer is leaking.

If it starts and runs OK after the use of the Hand Primer you have narrowed down the possible causes of your trouble.

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84 300D, 82 Volvo 244Gl Diesel