Engine Is Difficult To Start; Engine Runs But Knocks And Misses; Engine Will Not Idle; Engine Overheats - Toro 520XI Service Manual

DIESEL ENGINE
TROUBLESHOOTING (cont'd)

Engine is difficult to start.

Possible Cause
Improper starting procedure
Air in fuel
Inoperative glow plugs
Insufficient combustion air supply
Faulty injection nozzles
Clogged fuel filter
Incorrect injection pump timing
Low ambient temperature
Worn injection pump (hard starting warm)
Low compression
Engine runs but knocks or misses.
Possible Cause
Air in fuel
Dirt, water, or stale fuel in fuel system
Faulty injection nozzle(s)
Low compression
5

Engine will not idle.

Possible Cause
Air in fuel
Idle speed too low
The fuel injection pump is faulty
The fuel tank vent is restricted
Dirt or water is in the fuel system

Engine overheats.

Possible Cause
(3) air intake screens are dirty
More coolant is needed
Restricted air flow through radiator
Defective thermostat
The crankcase oil level is incorrect
Faulty thermostat
Excessive loading
5 - 4
Corrective Action
Activate glow plugs before attempting to start
Bleed nozzles, check for leaks on suction side of
system
Check fuse, glow plugs, and wiring
Check air filter and combustion air path
Test nozzles, clean or replace as necessary
Replace
Perform complete timing procedure
Activate block heater, check oil viscosity
Check fuel supply from nozzles
Perform cylinder leakage test
Corrective Action
Bleed nozzles, check for leaks on suction side of
system
Drain and flush fuel filter; add fresh fuel
Test nozzles, clean or replace as necessary
Perform cylinder leakage test
Corrective Action
Bleed nozzles, check for leaks on suction side of
system
Adjust idle speed
Repair or replace as necessary
Check hoses, clean, or replace
Drain and flush fuel system; add fresh fuel
Corrective Action
Clean with every use
Check and add coolant
Clean debris from radiator and cooling air path
Replace the thermostat
Fill or drain to the full mark
Replace
Reduce load; use lower ground speed
5xi Series Tractor Service Manual