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Chapter 8 FUEL SYSTEM
2.4.2 Fuel Injection Nozzle Spray - Inspect
When adjusting the nozzle opening pressure with the nozzle
tester, inspect for nozzle orifice clogging, fuel spray pattern
and dripping. If spray condition is faulty, clean or replace
the nozzle tip.
Checking points of fuel spray are as follows:
Injection spray is straight.
The spray is of fine fuel droplets without big drops.
No dripping is shown after injection.
Fuel Injection Nozzle Spray - Inspect
2.4.3 Nozzle Tip - Clean and Replace
(1) Remove the retaining nut.
(2) Remove the nozzle tip.
Nozzle Tip - Remove
(3) Clean the needle valve and body of nozzle tip.
When cleaning the needle valve and nozzle tip body,
use clean wash oil. Assemble the needle valve and body
in clean diesel fuel after cleaning.
(4) Tighten the nozzle tip tightening retainer nut to the
specified torque.
(5) If the spray pattern is still faulty after cleaning and
adjusting, change the nozzle tip with a new one.
New nozzle tips are coated with anti-corrosive agent.
Wash the nozzle tips before use. First wash them in
wash oil, and wash it again with clean diesel fuel before
installation.
Nozzle Tip - Clean
2.4.4 Push Rod - Inspect
Inspect the push rod visually. If its spring seat wears
unevenly, or its needle valve contact surface wears remark-
ably, or the cavitation occurs on its tapered area, replace the
push rod with a new one.
Push Rod - Inspect
Good
Large
angel
spray
After
dribble
Intermittent
spray
Whirling
spray
Faulty spray
(a) Be careful not to hit the nozzle tip.
(b) The needle valve and body are precision parts.
Handle them carefully, and do not change the
original valve and body combination.
Retaining nut
Nozzle tip end
Needle valve
Body
Spring seating face
local wear
Shim adjust type Screw adjust type
Needle valve
contact surface wear
Cavitation
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