III. Engine Servicing Procedures
U L-Series Diesel 25
Injector Pop-off Test
WARNING: FLUID FROM THE NOZZLE TESTER WILL SPRAY OUT UNDER
GREAT PRESSURE. IT CAN EASILY PUNCTURE A PERSON’S SKIN. KEEP
YOUR HANDS AWAY FROM THE NOZZLE TESTER AT ALL TIMES.
Use the following procedure to check
nozzle opening pressure, spray pattern,
chatter and leakage:
Mount the nozzle and holder assembly to
the gauge (J28829) and bleed the system of
air.
Open the pressure gauge valve and pump
the lever at a rate of one stroke per second.
Then check the opening pressure. When the
pressure gauge pointer decreases rapidly,
read pop-off value. (Refer to engine’s
specification sheet for values. An Indirect
Injection will have lower readings than a
Direct Injection engine.)
IMPORTANT! If the nozzle opening
pressure is not steady or cannot be
checked the trouble is with the nozzle
assembling procedure.
If the nozzle “pop-off” pressure does not meet factory pressures, disassemble the nozzle
and make a shim adjustment. The following size shims are available through AIPDN.
Shim Part Number Shim Size
mm
894176-9620 0.10
894176-9630 0.20
894176-9640 0.30
894176-9650 0.40
894176-9660 0.50
894176-9670 0.52
894176-9680 0.54
894176-9690 0.56
894176-9700 0.58
894176-9710 0.80