One is the pressure regulator, the other is a damper/accumulator. Accumulator goes before the pressure regulator.

You need to check the fuel pressure, it must be 29.5 psi or close. If low due to low fuel flow, car won't start. If too high, it will flood and run very rich.

If the injectors click while cranking, the EFI is working correcly and you have a fuel supply problem. If they don't click, check grounds and trigger points.'

Verify that the fuel pump is running and that you get 1 liter in 30 sec flow, pressure on the ring 29.5 psi.

Make sure you don't have a serious main injection ring leak!

Peter

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1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!