Fuel injection pump starvation with good a good lift pump is becoming more common as the bypass valve spring gets weaker with age.
A weak bypass spring allows too much lift pump pressure to flow back to the fuel tank = starving the injection pump for proper fuel volume.
The solution is to install a new (or good used) bypass valve.
MB# 0000747284
Diesel fuel return valve/banjo bolt, back of injection pump by engine block, at nylon return line going to fuel filter housing.
At this moment (September-22-2009), I have verified seven new units remaining in north America.
Application list:
OM615. 910, 911, 912, 913, 914, 915, 916, 917, 919, 930, 932, 936, 937, 938, 939, 940, 941, 942, 943, 944, 963, 970
OM616. 911, 912, 913, 914, 915, 916, 917, 930, 932 933, 934, 936, 937, 938, 939, 940, 960, 961, 963
OM617. 910, 912, 931, 932, 933, 950, 951, 952
OM621. 912, 913, 915, 916, 918, 919, 930, 931, 932
NOTE:
You should replace the banjo bolt/valve seal rings at this time.
Two of the following
Item Number: 007603012111
Main Category: MERCEDES BENZ
Description: SEAL RING, BANJO WASHER
Weight: 0.02
NOTE – All prices on special order parts subject to change without notice.