Sable V6-3.0L VIN U (1999)
Fuel Injector: Description and Operation
The fuel injectors are:
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electro-mechanical devices which both meter and atomize fuel delivered to the engine.
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mounted in the intake manifold and fuel injection supply manifold.
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positioned so their tips are directing fuel just ahead of the engine intake valve.
The fuel injector valve body consists of:
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solenoid and
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needle and valve assembly
An electrical signal from the Powertrain Control Module (PCM) activates the fuel injector solenoid causing the needle to move inward, off the seat. This
opens the orifice allowing fuel to flow through the orifice. Since the fuel injector flow orifice is fixed and the fuel pressure drop across the injector tip is
constant:
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fuel flow to the engine is regulated by how long the solenoid is energized.
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fuel is atomized by the contoured needle at the point where the fuel separates.