FUEL INJECTOR SERVICE

The fuel injector is located in the inlet manifold of the engine and sealed in between the manifold and fuel supply rail by rubber seals. A fuel pump pressurizes the system to normally about 2.5 - 3 bar.

The Engine Control Unit (ECU) determines the opening duration required for that combustion stroke. A current is transmitted to the solenoid of the injector.

The solenoid will magnetically lift the pintle valve needle from the seat of the injector, varying between 60 -100 microns. While the valve is raised, the pressurized fuel is forced through the orifice gap in the bottom of the injector, on to the pintle head and form a spray pattern shape as nominated by the head design.

The injector will remain open for anywhere between 1 – 20 milliseconds, at a frequency of 3 – 125 Hz, depending on the engines requirements. When the current is stops, a small coil spring pushes the valve needle to the pintle seat and stops any further fuel from passing through. 

The Injector Valve has the finest tolerances which in turn necessitates a clean and unobstructed flow.

Problems occur when the lacquers/chemicals in fuel cause a buildup of contamination, both inside the injector and on the pintle valve.

Filter blockage and internal contamination can reduce the injector flow rate by as much as 30%.

Although actual dismantling of an injectors internals is not possible, in most cases servicing injectors can return them to acceptable level of functionality.

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