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Fuel System
13---14
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.
Tightness of nozzle
Press down the tester pump lever until the pressure rises to
approx. 20 bar below the adjusting value. Maintain this pres-
sure for approximately 10 seconds and check whether drops
of fuel are formed on the point of the nozzle. If the injector
leaks, it should be cleaned or the nozzle should be changed.
N. Reconditioning injectors
1. Secure the injector in a suitable way.
2. Unscrew the nozzle cap nut. Remove the nozzle and the
parts inside the holder.
3. Clean the nozzle in cleaning fluid both inside and outside.
4. Clean the nozzle holes with a needle (including in cleaning
set 8360 83288).
5. Test the movement of the nozzle valve as follows:
213--- 30
Rinse the parts thoroughly in fuel or testing fluid. Pull the valve
out of the nozzle body to 1/3 of its length. If the fit is correct,
the valve should be able to slide down in the nozzle body
under its own weight. Turn the valve slightly and repeat the
test. Should the nozzle valve bind slightly, it should be
changed.
213--- 31
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2
3
4
5
6
7
8
9
Injector
1. Fuel inlet
6. Nozzle body
2. Leak---off fuel
7. Pressure chamber
3. Shim
8. Nozzle valve
4. Pressure spring
9. Nozzle hole
5. Valve stop spacer
6. Before assembling, all parts should be carefully cleaned in
clean fuel or testing fluid.
7. Put the same thickness of shim back as were fitted earlier.
Note possible adjustment of the opening pressure. Assemble
the rest of the injector. Note the position of the spring guide
and the valve stop spacer.
8. Tighten the nozzle cap nut by hand and then to
60 Nm
.