Manitowoc Grove 5540F Service Manual page 192

ENGINE AND ENGINE SYSTEMS
The following is a guide to the most common engine
performance complaints. The guide is to be used to
diagnose problems that are due to worn out components
and/or basic adjustments in the fueling system.
CONDITION: Engine will not start (Gasoline)
Verify each item below:
Fuel tank level.
Check fuel pump. Cycle
ignition switch ON/OFF,
fuel pump should run for 2
seconds.
Use a pressure gauge
connected to the fuel port.
Verify the fuel pressure
reads between 40-50 psi
(276-310 kPa).
Fuel injector is spraying.
Fuel injector is not leaking.
Spark plugs are not fouled
or wet.
CONDITION: Engine runs too rich on gasoline
Verify each item below:
Check for vacuum leaks to
the MAP sensor.
Restricted fuel return line.
LPG shut-off valve does
not close.
Check fuel pressure.
Should be between
40-50 psi (276 - 310 kPa)
at the fuel port.
Check for a bad MAP
sensor.
Check for a bad IAT, ECT
sensor.
Check for exhaust leaks
before the O2 sensor.
Check for excessive smoke
while running.
6-24
Remedy for each item:
Add fuel.
Check wiring and fuse/
relay.
Check and replace fuel
filter.
Check and replace fuel
pressure regulator.
Check and replace fuel
pump.
Check fuel injector wiring.
Replace injector o-ring or
injector.
Disconnect the fuel
injectors connectors for 15
seconds while cranking to
unflood the engine.
Remedy for each item:
Replace the hose.
Replace the fuel line.
Shut off LPG tank valve
and then replace or clean
the LPG shut-off valve.
Replace pressure
regulator.
Replace with a new MAP
sensor.
Replace with a new sensor.
Repair leaks in the exhaust
system.
Check and replace fouled
spark plugs.
Published 10-21-2010, Control# 198-04
5540F/YB5515 SERVICE MANUAL
CONDITION: Engine runs lean or misfires on gasoline
Verify each item below:
Visually inspect fuel filters
for restriction.
Use a pressure gauge
connected to the fuel port.
Verify the fuel pressure
reads between 40-50 psi
(276-310 kPa).
Check for clogged fuel
injectors.
Visually inspect MAP
sensor hose for breaks.
Check for a bad MAP
sensor.
Check for a bad IAT, ECT
sensor.
Check for intake manifold
air leaks.
CONDITION: Engine runs lean or misfires on LPG
Verify each item below:
LPG filter is not
contaminated and use air
pressure to verify
restriction.
Check for clogged fuel
lines.
LPG pressure regulator/
vaporizer is not frozen or
icing.
Visually inspect vacuum
hoses for breaks.
Verify timing with a timing
light.
Verify that the air filter for
the vaporizer is not
clogged.
Vaporizer primer button
becomes hard to depress
when the fuel is present.
Remedy for each item:
Replace fuel filter.
Replace pressure
regulator.
Clean or replace fuel
injectors
Replace the hose.
Replace with a new MAP
sensor.
Replace with a new IAT
sensor.
Repair leaks in the intake
system.
Remedy for each item:
Replace LPG filter.
Clean fuel lines.
Check for air leaks, purge
air from coolant hoses, add
coolant.
Repair as necessary.
Adjust distributor timing.
Replace air filter.
Replace or clean the LPG
fuel lock-off.