d. Check for Inoperative Fuel Injection Nozzles.
Run engine at 60 cycles and "cut out" each fuel injection
nozzle in turn by loosening the fuel injection line nut
attaching the line to the fuel injection pump.
Keep hands away from loosened
nuts while performing this test.
A decrease in engine speed with injection line
nut loosened indicates that the fuel injection nozzle for
that cylinder is functioning properly. If engine speed
does not decrease, the nozzle is defective and must be
removed, tested, adjusted, and cleaned.
e. Check for Inoperative Fuel Injection Pump.
(1) Do not replace the fuel injection pump
Figure 3-30. Day tank float, removal and
before having a compression test made.
(2) The compression test will indicate whether
indicates a pressure below specified
or not burned or stuck valves, worn or
minimum and little or no fuel is
scored pistons and sleeves, worn or stuck
observed from disconnected return
rings, etc., are causing the improper
line, an inoperative fuel transfer
engine operation. (Refer to direct and
pump is indicated. The pump must
general support maintenance.)
be removed, inspected, repaired, or
(3) If all causes for insufficient fuel supply
replaced as a unit.
have been eliminated, and the engine still
(d) If a pressure above 30 psi is
runs unevenly and normal engine
indicated by the gage, the fuel
performance is not obtained, the fuel
pressure relief valve is defective
injection pump will be considered at fault
and must be replaced as a unit.
and should be repaired or replaced.
(e) Stop engine and connect fuel return
line to fuel relief valve.