Air Bleeding In The Fuel Circuit; Injector Maintenance; Fuel Injection Nozzle - Doosan DP158L Series Operation & Maintenance Manual

Air bleeding in the fuel circuit

When the engine stops due to replacement of fuel filter, fuel
injection pump or insufficient fuel, you should perform air
bleeding.
1. Loosen the air bleeding plug (B) on the fuel filter.
2. Operate the priming pump by hand to bleed air inside the
fuel circuit.
3. Operate the priming pump until the air is discharged
completely through visual checking.
DANGER
Fuel is highly inflammable. Fire may occur when you
use fire near the engine when air bleeding in the fuel
circuit from the priming pump.
CAUTION
If you separate the parts where the seal ring (copper
seal ring, rubber coating seal ring, etc.) is assembled,
you should replace the seal ring with a new one. other-
wise, leakage may occur in the fuel filter connections,
preventing normal functioning.

Injector maintenance

• The injectors are designed to spray the fuel delivered by
the injection pump directly into the spherical combustion
chamber in the piston crown.
• The injector consists of the nozzle and the nozzle holder.
• A copper gasket fitted to the injector ensures gas-tight
seating and good heat dissipation.
• The opening pressure of the nozzle is adjusted by means
of shims at the compression spring.
B
A
DV2213164B
1
2
3
4
5
6
1. Rod type filter
2. Cap nut
3. Compression spring
4. Compression pin
5. Cap nut for fixed nozzle
6. Nozzle

Fuel injection nozzle

1. Install a nozzle to the nozzle tester.
2. Check the fuel injection pressure. If the pressure does
not satisfy the reference value, adjust the injection pres-
sure of the nozzle using an adjustment shim.
55
4. Regular inspection
7
8
9
10
11
12
7. Connect hole for fuel
delivery
8. Nozzle holder
9. Connect tube for overflow
10. Shim
11. Pin
12. Nozzle bush
DV2213022A
DV2213023A