We talk a lot about the increasing prevalence of direct injection engines in today's vehicles. This trend is largely due to the technology's ability to improve fuel efficiency and increase engine performance. Direct injection allows for more precise control of the fuel air mixture that's injected directly into the combustion chamber of each cylinder rather than being mixed with air before entering the combustion chamber. So is there any downside to direct injection? Well, one issue that your customers might come across is that direct injection engines can be more prone to carbon deposits. One reason is unique to direct injection and the remaining two are problems for poor fuel injection engines that are made worse by direct injection. The primary cause of these problems is that fuel and added detergents are not hitting the back of the intake valves. By injecting the fuel directly into the cylinder instead of at the back of the valve, the gasoline and detergents cannot clean the valve and port. Second, leaner mixtures and higher combustion pressures can make the problem worse over time. A direct fuel injection motor produces more energy from a given amount of fuel and air than a port fuel injection engine. Today's engines operate on the edge between optimal efficiency and a misfire. There's not much room for errors like hot spots in the combustion chamber or a worn spark plug. On a hot spot or sub-optimal flame front is created to do turbulent air, the amount of unburned fuel in the combustion chamber increases. When the valve opens during the intake stroke, it might come in contact with these byproducts and unlike the exhaust valve, the gases passing by are not hot enough to burn it off. Third, the intake valve goes into the combustion chamber regardless if it's port fuel injected or direct injected. When it does, for that small period, it's exposed to combustion byproducts that can stick to the neck of the valve. If the last combustion cycle is less than optimal, the intake valve is exposed. Some direct injection vehicles with variable valve timing can expose the valve to combustion byproducts as the valve's adjust, which creates a scavenging effect to either pull or leave behind a small amount of exhaust gas in the chamber to control nox emissions. Also, some turbocharged direct injection engines will leave the intake and exhaust valves open at the same time to keep the turbo spinning to reduce lag. Some carbon deposit problems are amplified due to the positive crankcase ventilation systems. The crankcase vapors can leave an oily film on the intake valve that's then baked into carbon. Some blame the valve overlap during the intake stroke that eliminates the need for an EGR valve. So what are the fixes? Well the first is preventative maintenance. Scheduled oil changes can keep the camshaft actuators working in optimal condition to control the exposure of the intake valves. High quality oils with lower volatility can reduce the volume of vapors in the crankcase. Intangue fuel injector cleaners also can help injectors maintain the correct spray pattern. This can ensure that the droplets have the correct size and distribution during ignition. Induction cleaning products and systems can put solvents and detergents onto the back of the intake and in the combustion chambers. These maintenance services can help reduce carbon buildup and possibly avoid having to take more drastic measures like blasting the valves with walnut shells. One of the most effective methods for preventing a carbon buildup problem is updating the engine management software. New software can reduce carbon deposits by reducing the exposure of the valves to conditions that cause carbon buildup through the adjustment of valve and spark timing. Thanks for watching.