Removing Injectors; Inspecting Injectors; Opening Pressure; Chattering Sound Properties - Valtra 6000 Workshop Manual

22. Fuel system
G. Removing injectors
1. Clean the injectors and the area around them. Disconnect
the delivery pipes and the leak ---off pipes.
3. Remove the injector attaching nuts (13 mm) and remove
the injector from the cylinder head. Fit protective plugs to all
connections. If the injector does not rise by hand, use puller
9051 71300.
4. Remove the sealing washers from the bottom of the injector
location in the cylinder head if they do no come out with the
injector
H. Inspecting injectors
N.B. When pressure testing the injectors, it is important to
avoid the nozzle end as the fuel jetting out easily penetrates
the skin. Also bear in mind that the fuel "mist" is dangerous to
inhale.
1. Clean the injector with cleaning fluid and a soft brush.
The carbon deposits must not be knocked off or removed in
any other way which may damage the nozzle.
9051 71300
2. Secure the injector in a test bench and check the follow-
ing:
--- injector opening pressure
--- the properties of the chattering (creaking) sound and the
form of the spray pattern
--- sealing of nozzle valve against its seat

Opening pressure

Pump a few times to fill the injector. Increase the pressure in
the injector until the chattering (creaking) sound becomes
audible. Read off the opening pressure of the injector. If the
opening pressure deviates from the given value (230±5 bar),
the injector should be taken apart and checked.
Adjustment is achieved by changing the shims. The thickness
of the shims varies from 1.00 ---1,90 mm and they are available
in increments of 0,05 mm. A thicker shim will raise the opening
pressure while a thinner one lowers it. A difference in shim
thickness of 0,05 mm changes the opening pressure by ap-
prox. 5,0 bar. As the opening pressure of the injector drops
slightly after adjustment, the opening pressure should be set
to approximately 10 bar above the value given in the specifica-
tions. This value applies both to new and used injector.

Chattering sound properties

Testing with a hand powered pump does not create the same
circumstances as when the injector is fitted in the engine. Only
with new nozzles are the test results reliable. With used
nozzles, there is no chattering (creaking) sound when the
tester is pumped at a certain rate. This has to do with the de-
sign of the nozzles.
However, with a rapid pumping on the tester handle, it should
be possible to hear the chattering (creaking) sound or/and
see a mist of the fuel jetting out.
113
Model
6000-- 8750
1. 9. 1992
Code Page
223 5