Fiat Fuel Injectors And Injector Parts Available Here. Fuel injectors and injector parts are critical components in your vehicle's internal combustion engine, because they provide the right amount of fuel to mix with oxygen in the combustion process and power your vehicle. They spray a variable amount of fuel depending on the engine's needs. A fuel injector can become clogged, dirty, rusted, leaky or broken, and in these cases it may need to be replaced. Replacing a fuel injector also requires the necessary accessory parts. If you notice a fuel smell or your engine is running inconsistently, it may be due to an issue with the fuel injectors.