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Fuel injectors: Testing

Prescribed oil- hydraulic oil with a viscosity 7-10 CST @ 50 degree Celsius. And before mounting open up the injector and clean with diesel oil. Never do atomization test on slide type fuel injector. Check the spring housing for attaching the injector to test kit by checking the position of the indicating lever provided.
Pressure testing procedure-
performing flushing- set air pressure 1bar, operate the change lever( larger lever, repeatedly until non air mixed air flows out from the drain hole.
 Test-

Opening pressure- set air pressure- 60 bar operate change lever and see the pressure at which injector open. (if more than prescribed replace springs if less add shims).
Sealing test and sliding test for injectors( objective- check for needle valve for tightness & the slide for correct closing.) set air pressure 1 bar, operate change lever until pressure is 80 bar below opening pressure, maintain the pressure for 10 sec and observe nozzle holes. push the change lever and oil should drain only through the drain hole.


Sliding test- upto 15 bar pressure drops slowly then upto 0 bar pressure drops quikley.( quick drop the valve is sticking or vent holes blocked).
Pressure test for o-rings- put a plug in case of drain hole and inspect the o-ring places for leakage, if leakage, its defective.

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Why atomisation test should not be done in slide type fuel valves

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