Carbon may be the building block of life, but it can wreak havoc on your engine.

Audi, Volkswagen, BMW and Mini engines utilize direct injection of fuel into the cylinder. Direct injection is where the fuel is sprayed at a very high pressure, directly into the cylinder through fuel injectors. The engine control module, or ECU, precisely controls all aspects of fuel injection, including the amount of fuel injected, timing, air to fuel ratio, how long the valves stay open and more. This process achieves better fuel economy and power because the combustion of fuel is more complete and the fuel burns more efficiently.

Air intake valves in all engines are exposed to air mixed with oil residue which can build up on top of the valves. Older, port style injection engines spray gasoline on the air intake valves. The fuel acts like a solvent and cleans the intake valves, promoting proper air flow. Engines with direct injection spray fuel directly into the combustion chamber. Because the fuel is sprayed directly into the combustion chamber, and not on the air intake valves, there is no way for the valves to be cleaned.

While direct injection technology uses less fuel and enhances engine performance, the side effects are not so good. Over time, as carbon builds up on the air intake valves, the air flow is restricted. Symptoms of dirty intake valves would be a rough idle, loss of power, and poor fuel economy. The check engine light may also be triggered. Never fear, there is a simple solution to this issue. We use pressurized ground walnut shells to remove oil and carbon residue that has built up on the intake valves. Direct injection engines need their intake valves cleaned manually at least every 100,000 miles.

We also recommend that customers have their oil changed at least every 5,000 miles, regardless of manufacturer maintenance schedules. More frequent oil changes will help to decrease the amount of carbon that builds up over time. It is impossible to say how much carbon will build up in your engine at any certain mileage, so regular service and inspections are an important part of engine maintenance to maintain the longevity of your car.

Whether you are a Royal Oak resident, or reside in the surrounding Metro Detroit area, such as Clawson, Troy or Madison Heights, please give us a shout if you suspect carbon build up in your engine. We look forward to taking care of your car’s needs. Call 248-971-7789.