By Larry Carley for Counterman
One of the hottest chemical categories these days is fuel cleaner additives.
There are basically three types:
Gas Treatments — low-dosage cleaner for regular use (every fill-up). These products are designed to supplement the detergents and cleaners that are in pump gasoline. All gasoline is required to contain a minimum level of cleaner — which is all you get with some low-priced brands. “Top Tier” gasolines contain higher levels of detergents and cleaners, but only some brands qualify as Top Tier products. For the others, using a supplemental gas treatment is recommended.
Injector Cleaners — higher-dose cleaners that are formulated to help keep fuel injectors clean, and to clean dirty injectors. Fuel deposits can restrict and even clog the injector nozzles, reducing fuel flow and disrupting the spray pattern of the injector that is critical for good fuel atomization, performance and fuel economy. These products provide an extra dose of cleaner that loosens and flushes away deposits inside the injectors.
Complete Fuel System Cleaners — These typically contain the highest concentrated dosage of cleaner to not only clean injectors, but also dirty intake valves, combustion chambers and the tops of the pistons. Hard carbon deposits that form on the intake valves can obstruct airflow. The problem is made worse if the valve guides and seals are worn. Deposits that form inside of the combustion chamber and on the tops of the pistons can reduce the volume of the combustion chamber and increase compression, which increases the risk of pre-ignition and detonation (spark knock). Hard carbon deposits on these parts can be difficult to remove, and require a high-strength cleaning product that not only loosens the carbon but can also withstand the high temperatures inside the combustion chamber.
One of the more challenging applications are late-model engines with Gasoline Direct Injection (GDI). With GDI, fuel is injected directly into the combustion chamber under high pressure. On port-injected engines, the injectors are located in the intake manifold and spray fuel into the intake ports. This washes the intake valves and helps keep them clean (provided there is an adequate level of detergent in the gasoline to keep the valves clean). But there is no such cleaning action with GDI, so thick carbon deposits can build up on the intake valves and hurt performance and fuel economy. The problem is worse in some engines (such as VW GDI engines) where there is a lot of oil vapor recirculating back into the intake manifold via the PCV system.
If a fuel tank additive is not strong enough to clean dirty injectors, valves, combustion chambers of pistons, professional grade products that are fed directly into the injector supply rail and/or throttle body might be recommended. These include engine “top cleaners” that have to soak for a period of time with the engine off to loosen stubborn deposits. An oil change is recommended after using a top cleaner because some of the cleaner will get past the rings into the crankcase.
Dirty throttle bodies can also affect performance. Aerosol throttle cleaner is a good product for removing varnish deposits from the throttle body and intake manifold. Some intake manifold cleaners are designed to be fed into the manifold through a vacuum port while the engine is running.
Dirty mass airflow sensors can also cause driveability problems and set fuel mixture codes. An aerosol electronics cleaner or MAF sensor cleaner is the only type of product that should be used to clean a dirty MAF sensor.
