Checking Fuel Circuit For Leakage - Komatsu ecot3 PC300LC-8 Shop Manual

30 Testing and adjusting

Checking fuel circuit for leakage

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Very high pressure is generated in the high-
pressure circuit of the fuel system. If fuel
leaks while the engine is running, it is dan-
gerous since it can catch fire.
After testing the fuel system or removing its
parts, test it for fuel leakage according to the
following procedure.
a Clean and degrease the engine and the parts
around it in advance so that you can test it easily
for fuel leakage.
1. Spray color checker (developer) over the fuel
supply pump, common rail, fuel injector, and
joints of the high-pressure piping.
2. Run the engine at speed below 1,000 rpm and
stop it after its speed is stabilized.
3. Inspect the fuel piping and devices for fuel
leakage.
a Check mainly around the high-pressure cir-
cuit parts coated with the color checker for
fuel leakage.
a If any fuel leakage is detected, repair it and
check again from step 1.
4. Run the engine at low idle.
5. Inspect the fuel piping and devices for fuel
leakage.
a Check mainly around the high-pressure cir-
cuit parts coated with the color checker for
fuel leakage.
a If any fuel leakage is detected, repair it and
check again from step 1.
6. Run the engine at high idle.
7. Inspect the fuel piping and devices for fuel
leakage.
a Check mainly around the high-pressure cir-
cuit parts coated with the color checker for
fuel leakage.
a If any fuel leakage is detected, repair it and
check again from step 1.
PC300, 350-8
8. Run the engine at high idle and load it.
a When checking while the components to be
checked are mounted on the machine, stall
the torque converter or relieve the hydraulic
pump.
9. Inspect the fuel piping and devices for fuel
leakage.
a Check mainly around the high-pressure cir-
cuit parts coated with the color checker for
fuel leakage.
a If any fuel leakage is detected, repair it and
check again from step 1.
a If no fuel leakage is detected, check is com-
pleted.
SEN02625-06
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