Quality fuel injector cleaners that use polyether amine chemistry do clean the fuel lines. The additive also needs to be properly sprayed through the fuel system.
Fuel injectors work by pumping a pressurized amount of fuel into a small opening. Overtime these injectors build up carbon deposits; these deposits disrupt the flow of fuel to and from the engine.
Two Common Types of Additives Used in Fuel Injector Cleaners
Polybutene Amine (PBA)
PBA is commonly used as an additive in gasoline mixtures. This additive, when used with the recommended dosages, prevent build-up from inside the system. Unfortunately, over-using PBA additives will contribute to carbon deposits inside the engines chambers.
Polyether Amine (PEA)
PEA is a higher grade fuel additive that helps maintain combustion chambers. PEA is commonly used in dealership rated fuel system cleaning services.