Ed:

Do you get any fuel delivered with the pressure valve spring out? If you do, the seal is shot -- its underneath the steel "sleeve" that the pressure valve and spring fit onto.

If not, you have an internal problem with the pump and will have to have it serviced -- it simply is not possible to do this at home. The two most likely causes are a broken return spring or a scored plunger, niether of which can be replaced without complete pump disassembly and recalibration.

I repeat, it is NOT possible to do a pump repair at home -- if you take it apart, you will have a non-funtioning pump. Yes, I know all sorts of folks claim to do injection pump repairs on the workbench, but I've yet to see one properly working when they were done!

Peter

__________________
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!