TEST FUEL SUPPLY PUMP FOR LEAKS
Fuel delivery pressure should be checked before
removing supply pump from injection pump. See CHECK
SUPPLY PUMP OPERATION in Group 115 CTM134.
1. Connect compressed air line (A) to a pressure gauge
(B) and to the pump inlet fitting. The air line should
have a regulating valve to control pressure.
2. Cap or plug supply pump outlet fitting (C).
3. Submerge supply pump in a container of clean diesel
fuel. Regulate air pressure to 200 kPa (2.0 bar) (29
4. Move plunger or roller tappet in and out by hand. No
air bubbles should appear around bore.
NOTE: If bubbles appear, it is an indication that either the
Testing Fuel Supply Pump for Leaks
seal is defective or that the plunger or roller
tappet is worn.
IMPORTANT: If enough diesel fuel leaks past the
supply pump seal, serious damage to
the injection pump or engine (or both)
could occur. Fuel leakage past plunger
or roller tappet dilutes engine oil.
5. If pump leaks, replace complete pump assembly.