Toyota currently uses four different types of fuel injectors depending on engine application. These can be broken down into pintle type and hole type (cone valve and ball valve), high resistance and low resistance.
Pintle Type Injector - This was the original design used on early Conventional and EFI/ TCCS engines. This injector gets its name from the type of valve used to control fuel atomization and flow. It offers good atomization of fuel but is susceptible to deposit buildup on the pintle valve. Deposits cause restriction to fuel flow promoting lean fuel delivery and altered injector spray pattern.
Hole Type Injector - Hole type injectors were introduced on later model EFI/tCcS engines to reduce concerns with injector deposits. The inject.on valve is recessed from the tip of the injector and fuel is delivered through holes drilled in a director plate at the injector tip. The hole type injector offers good fuel atomization while demonstrating better resistance to deposit buildup compared to the pintle design. There are currently three designs of hole type injectors in use, including a side feed injector used on the 3S-GTE and 2TZ-FE engines.
High And Low Resistance Injector Windings There are two different types of injector coil windings used depending on the type of drive circuit used and whether or not an external resistor is being used.
Low resistance injectors, which typically range between 2 - 3 W @ 70'F, are used with an external resistor in a voltage controlled driver circuit. Low resistance injectors are also used without an external resistor in a current controlled driver circuit.
High resistance injectors, which typically run about 13.8 W @ 70'F, do not require the use of an external resistor in a voltage controlled driver circuit.
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