Starting Performance Is Poor (Starting Always Takes Time) - Komatsu 170-3 Series Shop Manual

TROUBLESHOOTING
S-1

Starting performance is poor (starting always takes time)

General causes why starting performance is poor
• Defective electrical system
• Insufficient supply of fuel
• Insufficient intake of air
• Improper selection of fuel
• Defective HPI sensor
• Defective HPI actuator
Confirm recent repair history
Degree of use of machine
Starting performance became worse gradually
Engine starts easily when warm
Non-specified fuel is being used
Replacement of filters has not been carried out according to Operation Manual
Engine oil must be added more frequently
Charge caution lamp lights up
When preheating, preheating indicator lamp does not light up
Dust indicator is red
Air breather hole in fuel tank cap is clogged
Starting motor cranks engine slowly
When engine is
Little fuel comes out even when injection pump sleeve nut is loosened
cranked with
starting motor, Little fuel comes out even when fuel filter air bleed plug is loosened
When exhaust manifold is touched immediately after starting engine, temperature
of some cylinders is low
Engine does not pick up smoothly, and combustion is irregular
There is hunting from engine (rotation is irregular)
Blow-by gas is excessive
Difficult to stop engine
Inspect air cleaner element directly
When compression pressure is measured, it is found to be low
Inspect fuel filter, strainer directly
When negative pressure at inlet port of fuel pump is measured, it is found to be high
When pressure at outlet port of fuel pump is measured, it is found to vary
When pressure at outlet port of fuel pump is measured, it is found to be low
Inspect fuel pump directly
Inspect fuel shut-off valve directly
Inspect timing rail actuator screen directly
When temperature of exhaust gas of each cylinder is measured, there are some
cylinders that are low
Inspect injector directly
When specific gravity of electrolyte and voltage of battery are measured, one of
them is low
When starting switch is turned to HEAT, heater mount does not become warm
Is voltage 26 - 30V between alternator terminal B and terminal E with
engine at low idling?
Inspect sensor directly (Output voltage and resistance)
Inspect actuator directly (Resistance and filter for clogging)
12-106
Operated for long period
Yes
No
Remedy
S-1
Causes
170-3 SERIES