Fuel System Operation and Tests
Defective O-ring seal.
Replace O-ring seal.
TEST FUEL SUPPLY PUMP FOR LEAKS--
IN-LINE INJECTION PUMP
Fuel delivery pressure should be checked before
removing supply pump from injection pump. (See FUEL
SUPPLY PUMP OPERATION--IN-LINE INJECTION
PUMP, earlier in this group).
1. Connect compressed air line (A) to a pressure gauge
(B) and to supply pump inlet fitting. 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 roller tappet in and out by hand. No air bubbles
should appear around roller tappet.
NOTE: If bubbles appear, it is an indication that either the
O-ring seal is defective or tappet is worn (or
IMPORTANT: Serious injection pump or engine
damage could occur, if enough diesel
fuel leaks past spindle and seal. Fuel
leakage past spindle dilutes engine oil.