603.960 perhaps? Crank the engine with the oil filler cap off and see if the cam is spinning. It'll be less than a good thing if the cam isn't spinning either. Then pull the timing port plug (17mm head bolt aft of the fuel pump). Use a mirror to see if the timing wheel is spinning. If there's nothing to see, set the crank to 15 ATDC #1 and feel for a lug on the timing wheel. If nothing, give the crank another full turn to 15 ATDC #1 and try again. In fact, you can probably rest a stick against the timing wheel to check if it's turning. I don't know if the pump is driven off the IP's main shaft or another shaft. If it's the same shaft then the test will tell you nothing you don't already know.

Sixto
95 S420
91 300SE
87 300SDL
83 300SD