I've got a OM602 engine. No pump. Self Priming. Sorta. Tank is behind the back seat so it's more of gravity fed till the pump. How full is the fuel tank? Did you tighten the hose connectors? When I changed the primary and secondary it took a while for the secondary filter to fill up. I had to turn the key for 15 sec. Wait a minute. 15 Sec wait a minute.. Like 7 times.
92 300D 2.5L OM602 OBK #59