Engine Lacks Output (Or Lacks Power) - Komatsu 170-3 Series Shop Manual

TROUBLESHOOTING
S-6

Engine lacks output (or lacks power)

Measure the engine speed and judge if the problem is in the engine or on the machine.
General causes why engine lacks output
• Insufficient intake of air
• Insufficient supply of fuel
• Improper fuel used
(if non-specified fuel is used, output drops)
• There is overheating
See Troubleshooting S-14.
• Defective HPI sensor
• Defective HPI actuator
Confirm recent repair history
Degree of use of machine
Power was lost
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
Dust indicator lamp is red
When engine is
Fuel pump outlet port coupler is pushed, almost no fuel comes out
cranked with starting
Fuel pump outlet port coupler is pushed, air comes out together with fuel
motor, and
When exhaust manifold is touched immediately after starting engine, temperature of some cylinders is low
Black
Color of exhaust gas
Blue under light load
Clanging sound is heard from around cylinder head
Noise of interference is heard from around turbocharger
Engine pickup is poor and combustion is irregular
There is hunting from engine (rotation is irregular)
High idling speed of engine is low
Blow-by gas is excessive
Inspect air cleaner element directly
When turbocharger is rotated by hand, it is found to be heavy
When compression pressure is measured, it is found to be low
Inspect valve clearance directly
When pressure at outlet port of fuel pump is measured, it is found to vary
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 be low
When temperature of injector of each cylinder is measured, there are some cylinders that are low
Inspect sensor directly (Output voltage and resistance)
Inspect actuator directly (Resistance and filter for clogging)
Check part No. of controller calibration data
12-112-2
Operated for long period
Suddenly
Gradually
Causes
Remedy
S-6
170-3 SERIES