Poor performance could signal problems with carbon deposits

Minor inconveniences often are easy to overlook. That’s especially true for auto maintenance, where something like an engine knock or a minor rattle may get drowned out by music or traffic noise.

Those little nuisances can turn into expensive repair bills if left unattended, however.

For instance, carbon build-up inside the engine can sap your vehicle’s performance and rob it of gas mileage. Symptoms are easy to diagnose if you know what to look for–reduced fuel economy, pinging during acceleration, sooty exhaust.

Carbon build-up is a generic term used to describe the dark sticky deposits that form on internal engine components like valves and manifolds. They are the byproducts of combustion and will accumulate at different rates based on things like fuel quality and how well the engine is running.

For example, a misfiring spark plug or too-rich fuel mixture can result in more deposits over a shorter period of time. These deposits form in all internal combustion engines during normal operation, and they are not a problem if your vehicle gets seasonal maintenance.

Heavy deposits disrupt the smooth air flow in the engine. Eventually, bits of carbon may break off and damage the engine and catalytic converters or even affect sensors.

Excessive deposits can cause that pinging sound you may hear when accelerating. Sometimes the problem is called “octane creep” since using premium fuel can mask the problem.

High-performance vehicles are particularly susceptible to problems with carbon build-up. They often require premium gas to operate efficiently. Using a lower octane fuel can cause reduce overall performance and fuel economy.

What’s the answer?

The easiest advice is to use the proper grade of fuel for your engine. If a vehicle is designed to run on premium gas, don’t try to economize by using regular fuel or you’ll increase build-up deposits.

If your vehicle has symptoms of carbon build-up, ask your service advisor for an inspection. It only takes a few minutes to determine if there’s a chronic problem.

Here are some basic facts all drivers should know about carbon deposits:

• Carbon build-up occurs naturally. Although small amounts of deposits are no cause for concern, excessive build-up may damage the engine or catalytic converter and sensors.
• Beware of the tell-tale signs for carbon buildup. That includes reduced fuel economy, pinging during acceleration or increased emissions.
• Use the recommended fuel. Lower octane fuel in a high-performance engine increases problems with carbon build-up.
• Clean it out. If you suspect problems associated with carbon build-up, have your service advisor inspect the engine and recommend the best way to remove deposits. The solution may involve pressure cleaning the fuel system or simply replacing spark plugs.