Chapter 3 Fuel Injection Equipment
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3,4JH3(B)(C)E
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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