External fuel correction = electronic control. You don't have it.

There are two nuts on the injection pipe at the IP -- the top one holds the line on the pressure valve assembly and the other on is the nut for the pressure valve holder. Take the line off, then unscres the pressure valve holder. The seal is an o-ring at the bottom and a copper ring. Have a care to get the bits all back in correctly, and oil or coat the threads with vasoline before replacing the pressure valve holder -- the torque spec is for lubricated threads, not dry threads. Clean everything VERY carefully before dissasembly and again before replacement -- grit or dirt here will cause running problems such as leaking pressure valves (no injection at idle) or sticking injectors. Not fun, nor cheap.

The later pumps use a multi-spline instead of a nut on the pressure valve holders that takes the special wrench. Otherwise much the same.

Later 617 pumps and 601/602/603 pumps have a locking bracket that must be removed to torque or remove the pressure valve holder. 615 pumps have a clamp between the holders to prevent them from rotating.

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!