Chapters Fuel Injection Equipment
8. Troubleshooting
4LHA Series
Fault
Cause
Remedy
3.
Engine's
output
is
insufficient.
Defective
injection
timing, and
other failures.
(1) Knocking sounds caused by improper (too fast) injection timing.
(2) Engine overheats or emits large amount of smoke due
to improper (too slow) injection timing.
(3) Insufficient fuel delivery from feed pump.
Inspect and adjust
Inspect and adjust
Repair
or replace
3.
Engine's
output
is
insufficient.
Nozzle
movement
is
defective
(1)
Case
nut is loose.
(2) Defective injection nozzle performance.
(3) Nozzle spring is broken.
(4)
Excessive
oil leaks from nozzle.
Inspect and retighten
Repair
or replace nozzle
Replace
Replace
nozzle assembly
3.
Engine's
output
is
insufficient.
Injection
pump is
defective.
(1) Max. delivery
limit
bolt is screwed in too far.
0 Plunger is worn.
(3)
Injection
amount is not uniform.
(4)
Injection
timings are not even.
(5) The 1st and 2nd levers of the governor and the control
rack of the injection pump are improperly lined up.
(6) Delivery stopper is loose.
(7) Delivery packing is defective.
(8) Delivery valve seat is defective.
(9) Delivery spring is broken.
Adjust
Replace
Adjust
Adjust
Repair
Inspect and retighten
Replace
packing
Repair
or replace
Replace
4.
Idling
is rough.
(1) Movement of control rack is defective.
1) Stiff plunger movement or sticking.
2)
Rack
and pinion
fitting
is defective.
3) Movement of governor is improper.
4) Delivery stopper is too
tight.
(2) Uneven injection volume.
(3)
Injection
timing is defective.
(4) Plunger is worn and fuel injection adjustment is
difficult.
(5) Governor spring is too weak.
(6)
Feed
pump can't feed oil at low speeds.
(7) Fuel supply is insufficient at low speeds due to clogging
of fuel
filter.
Repair
or replace
Repair
Repair
Inspect and adjust
Adjust
Adjust
Replace
Replace
Repair
or replace
Disassemble
and clean,
or replace element
5.
Engine runs at high
speeds,
but cuts out
at low speeds.
(1) The wire or rod of the accelerator is caught.
(2) Control rack is caught and can't be moved.
Inspect and repair
Inspect and repair
6. Engine doesn't reach
max.
rpm.
(1) Governor spring is broken or excessively worn.
(2)
Injection
performance of nozzle is poor.
Replace
Repair
or replace
7. Loud knocking.
(1)
Injection
timing is too fast or too slow.
(2)
Injection
from nozzle is improper.
Fuel
drips after each injection.
(3)
Injection
nozzle starting pressure is too high.
(4) Uneven injection.
(5) Engine overheats, or insufficient compression.
Adjust
Adjust
Adjust
Adjust
Repair
8. Engine
emits
too much
smoke.
When
exhaust
smoke
is
black:
(1)
Injection
timing is too fast.
(2) Air volume intake is insufficient.
(3) The amount of injection is uneven.
(4)
Injection
from nozzle is improper.
Adjust
Inspect and repair
Adjust
Repair
or replace
8. Engine
emits
too much
smoke.
When
exhaust
smoke
is
white:
(1)
Injection
timing is too slow.
(2) Water is mixed in fuel.
(3) Shortage of lube oil in the engine.
(4) Engine is over-cooled.
Adjust
Inspect fuel system,
and
clean
Repair
Inspect
3-2-49
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