English Service Manual Mitsubishi Sq-Series Diesel Engines - Mitsubishi S4Q User Manual

CAUSES OF ENGINE PROBLEMS AND
REMEDIES
Causes
Fuel is not supplied to
injection pumps properly
Irregular injection pump
operation
Insufficient fuel injection
volume (by injection pump)
Excessive fuel injection
volume
Fuel injection nozzle(s)
defective
Fuel injection timing is too
advanced
Fuel injection timing is too
retarded
156 / 174
Details of Causes
Fuel tank supply valve is closed
No fuel in tank
Fuel lines restricted
Air in fuel system
Fuel leakage
Fuel filter is clogged
Inadequate air bleeding
Sticking of plunger(s)
Worn plunger(s)
Worn bearing(s)
Damaged plunger spring(s)
Loose plunger pinion(s)
Delivery valve(s) defective
Damaged delivery valve spring(s)
Catching of governor stop lever link
Control rack does not move
Seizing of plunger(s)
Worn plunger(s)
Worn bearing(s)
Loose plunger pinion(s)
Full-load setting of governor does not move
Stop lever sticking in "increase" position
Full-load setting of governor improper
Loose plunger pinion(s)
Seizing of nozzle tip needle
Nozzle tip seat(s) defective
Damaged nozzle spring(s)
Fuel injection pressure is too low
Carbon deposits on packing at nozzle tip(s)
Faulty mounting angle of injection pump
Timing gears incorrectly installed
Faulty mounting angle of injection pump
Timing gears incorrectly installed
Worn fuel injection pump bearing
Open the valve.
Add fuel.
Repair or clean fuel pipes with compressed air.
Tighten mounting sections or replace fuel pipes.
Retighten connections.
Clean or replace filter element.
Conduct air bleeding.
Disassemble and replace parts.
Disassemble and replace parts.
Disassemble and replace parts.
Disassemble and replace parts.
Reinstall by matching marks.
Replace parts.
Replace parts.
Repair link properly and set lever to neutral position.
Supply lubricant, or disassemble and repair.
Disassemble and replace parts.
Disassemble and replace parts.
Disassemble and replace parts.
Reinstall by matching marks.
Readjust governor setting on bench.
Repair link properly and set lever to neutral position.
Adjust governor setting on bench.
Reinstall by matching marks.
Repair or replace.
Repair or replace.
Replace parts.
Change adjusting shim and set standard injection
start pressure using nozzle tester.
Remove carbon deposits.
Tilt injection pump toward outside of engine and
adjust timing.
Correct timing gear engagement.
Tilt injection pump toward outside of engine and
adjust timing.
Correct timing gear engagement.
Replace parts.
ENGLISH
Service Manual Mitsubishi SQ-Series diesel engines
TROUBLESHOOTING
Remedies
Version 08/2004