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III. Engine Servicing Procedures
Injector Pop-off Test
WARNING: FLUID FROM THE NOZZLE TESTER WILL SPRAY OUT UNDER GREAT
PRESSURE. IT CAN EASILY PUNCTURE A PERSONS 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 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 engines
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. If the pop-off pressure is low, increase the shim thickness.
The following size shims are available through IR.