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Chapter 3 Fuel Injection Equipment
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7. Trouble shooting of fuel injection pump
Basic check points
7-1 Troubleshooting of fuel injection pump
Complete
repair means not only replacing defective
parts, but finding and eliminating the cause of the trouble
as well. The cause of the trouble
may
not necessarily be
in the pump itself, but may be in the eng·ine or the fuel
system.
If the pump is removed prematurely, the true
cause of the trouble may never be known Before remov•
ing the pump from the engine, at least go through the
basic check points given here.
• Check for breaks or oil leaks throughout the fuel sys-
tem, from the fuel tank to the nozzle.
• Check the injection timings for all cylinders. Are they
correctly adjusted? Are they too fast or too slow?
• Check the nozzle spray.
• Check the fuel delivery Is it in good condition? Loosen
the fuel pipe connection at the injection pump inlet, and
test operate the fuel feed pump.
7-2 Major faults and troubleshooting
Fault
Causa
1.
Engine
Fuel not
(1)
No fuel in the fuel tank.
won't
delivered
to
(2) Fuel lank cock is closed.
start
injection
(3) Fuel pipe system is clogged
pump
(4)
Fuel fitter element is clogged
(5)
Air is sucked into the fuel due to defective connections
in the piping from the fuel tank to the fuel pump.
(6)
Defective valve contact of feed pump
(7)
Piston spring of feed pump is broken.
(8)
Inter-spindle or tappets of feed pump are stuck
Fuel
(1)
Defective connection of control lever and accel. rod of
delivered
injection pump.
to injection
(2) Plunger is worn out or stuck.
pump.
(3) Delivery valve is stuck
(4)
Control rack doesn't move
(5)
Injection pump coupling is damaged, or the key Is broken.
Nozzle
(1)
Nozzle valve doesn't open or close normally
doesn't work.
(2) Nozzle seat is defective.
(3) Case nut is loose.
(4)
Injection nozzle starting pressure is too low
(5)
Nozzle spring is broken.
(6)
Fuel oil filter is clogged.
(7)
Excessive oil leaks from the nozzle sliding area.
Injection
(1) Injection timing is retarded due to failure of the coupling.
timing is
(2)
Camshaft is excessively worn.
defective.
(3) Roller guide incorrectly adjusted or excessively worn.
(4)
Plunger is excessively worn.
2. Engine starts, but
( 1) Fuel pipe is clogged.
immediately stops.
(2) Fuel filter is clogged.
(3) Improper air-tightness of the fuel pipe connection.
or pipe is broken and air is being sucked in.
(4) Insufficient fuel delivery from the feed pump
3-36
Remedy
Resupply
Open
Clean
D'lsassemble and clean,
or replace element
Repair
Repair or replace
Replace
Repair or replace
Repair or adjust
Repair or replace
Repair or replace
Repair or replace
Replace
Repair or replace
Repair or replace
Inspect and tighten
Adjust.
Replace
Repair or replace
Replace the nozzle assembly
Adjust
Replace camshaft
Adjust or replace
Replace plunger assembly
Clean
Disassemble and clean,
or replace the element
Replace packing repair pipe
Repair or replace
Printed in Japan
HINSHJ-H8009
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Troubleshooting
