Can You Use a Carburetor Cleaner on a Throttle Body in Fuel Injected Car?by Richard Rowe
In a car guy's mind, if it smells like gas, then it probably is; if it smells like paint thinner but costs more, then its probably a conspiracy on the part of a manufacturer to charge you three times as much for a different can. But you may be surprised to learn that while they may seem very similar, carburetor and throttle body cleaners are quite different in terms of composition and function.
Carburetors vs. Throttle Bodies
The primary difference between a throttle body and a carb is that the carb carries both air and fuel, while the TB carries only air. This changes the approach that manufacturers must take to cleaning them, since gasoline and the contaminants in it leave a gummy residue -- not unlike fiberglass resin -- on the inside of the carb. The throttle body usually gets dirty with heavier contaminants such as carbon, soot and oil from the crankcase ventilation system.
The basic problem that any throttle body faces is that heavy particulates and liquid oil stick to it, which means you'll want to clean it with something that will both dissolve the carbon and help prevent particulate sticking in the future. The simplest way to prevent sticking is to use some kind of surfactant or soap that embeds into the surface. Carburetors, on the other hand, require a more aggressive solvent to dissolve resins in the bores, but need something that quickly evaporates or dissolves in the gasoline when the engine starts.
Basic Chemical Structure
Both carb and TB cleaner contain between 20 and 30 percent acetone, which is a good all-purpose solvent for any kind of hydrocarbon. Carburetor cleaners tend to use the very aggressive but quickly evaporating toluene to melt resins, whereas TB cleaners tend to use the slower evaporating and less-aggressive xylene to break apart heavy soot particles and oil. TB cleaners generally contain higher quantities of glycol ethers, which slowly evaporate, repel water and act as a "soap" to make the metal surface slick.
Contrary to common belief, carb cleaner isn't just "throttle body cleaner with some extra oil to lubricate the parts." Carb cleaners specifically are designed to aggressively dissolve a thin layer of resin then evaporate as quickly as possible. TB cleaners, on the other hand, are lingerers; they sit in place for a while, breaking heavy carbon apart and leaving a slick surface to keep carbon and oil from sticking in the future.
Yes, you can use carburetor cleaner to clean a throttle body, but not without making a few compromises. Carb cleaner doesn't penetrate and hang around to break up heavy deposits, so you'll end up having to use more of it in multiple passes to remove heavy carbon buildup. And when you're done, you've got a TB that's squeaky clean, but will quickly accumulate more carbon and soot buildup. So, while you can use carb cleaner on a throttle body, you're better off spending the same $2.95 on TB cleaner specifically engineered for the task.
- Perry's Chemical Engineers' Handbook, Fourth Edition; Don Green
Richard Rowe has been writing professionally since 2007, specializing in automotive topics. He has worked as a tractor-trailer driver and mechanic, a rigger at a fire engine factory and as a race-car driver and builder. Rowe studied engineering, philosophy and American literature at Central Florida Community College.