BEST FROM YOUR
BY RON FAUSNIGHT the tip where the injector actually time. Any deposits that hinder the Buildup on your
sprays the fuel into the intake port spray will usually increase droplet size engine’s valves
uel system deposits can be an or, in some vehicles, directly into and cause the spray to stream instead (ABOVE) can really
ongoing problem with many the combustion chamber. Whenever of mist. These larger droplets burn clog things up, while
types of vehicles, from a pro the engine is shut down, it remains more slowly because there is less dirty, abused fuel
spec track car down to your family hot and any remaining droplets surface area exposed to the air. The injectors (RIGHT)
mini-van. The severity of these from the fuel spray dry and bake, slower burn reduces the power and don’t offer the best
deposits varies among vehicles and leaving behind a residue of heavier fuel economy of the engine and may spray pattern. The
even from cylinder to cylinder in the hydrocarbons and additives. Over increase emissions. Injector deposits end result of either is
same vehicle. But how do these time, this residue hardens and can can also cause cold start problems decreased engine
deposits form? Why do they matter? block spray holes. Even tiny amounts and rough idle. performance.
And how do we get rid of them? Let’s may affect fuel ﬂow patterns. Intake valves build deposits
start by looking at some of the causes The hotter the location, the harder because fuel sprayed into the port
and locations of deposits and how and more carbon-like the deposits wets the valve as air enters the
they impact your fuel system. become. For optimal combustion, the combustion chamber. This area gets
Fuel injectors tend to build fuel spray must be a ﬁ ne mist sprayed hot, so the volatile fuel evaporates
deposits in the pintle area. This is in the proper direction at the proper leaving behind heavier components.
40 august www.scca.com
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The organic matter carbonizes and products that generally do not contain
builds over repeated cycles. enough detergent to clean up old
As these deposits build, they deposits. Also, the beneﬁt runs out
partially block airﬂow. After the when the tank of treated fuel runs out.
deposit is formed, fuel sprayed from Fuel injector cleaners should clean
a port fuel injector may absorb into up fuel injector deposits. Check the
the deposit. Because it is not getting label to see whether the product
to the combustion chamber, it requires regular use with each ﬁ ll up
cannot produce maximum power or provides a thorough cleaning that
during acceleration. Extreme will last for several thousand miles.
deposits can affect valve operation. Fuel injector cleaners usually do not
For example, a piece of deposit have enough detergent to clean
could break free and prevent the intake valves and usually cannot
valve from closing completely. This clean combustion chamber deposits.
can cause loss of compression and Complete fuel system cleaners
potentially serious engine damage. should clean up fuel injectors, intake
Less extreme results can be loss of valves and combustion chambers.
power and fuel economy. Not only do they generally contain a
The combustion chamber builds greater quantity of detergent, they
deposits depending on the may contain a special type of
composition of the fuel. Gasoline is a detergent that can perform in the
mixture of molecules of many extreme environment of the
different sizes and shapes. The larger combustion chamber where the fuel