What You Need to Know About Carbon and Fuel Ratios

Injectors Fuel Ratio

Every time the accelerator is pressed, you control how much fuel and air the engine takes in. These are mixed together and drawn into the combustion chamber of an engine cylinder. At idle, the scientific community would say a perfect air/fuel ratio would be 14.6:1; however this will vary depending on air temperature, engine configuration and especially on whether the engine is naturally aspirated or turbo/supercharged. Recently, gasoline direct injection (GDI) engines have forced equipment manufacturers and fuel suppliers to take a closer look at the blending of air and fuel in the combustion chamber due to the engine design rapidly building up unburned fuel, and, in many cases, motor oil, which forms carbon deposits in and on injectors and intake valves. Look at these pictures: 



One of the issues of a combustion engine is that it will produce carbon even under optimal conditions; however, if the ratios are less than optimal, even more carbon can be produced. This carbon accumulates in the air intake, combustion chamber, and exhaust system restricting the vehicle’s ability to breathe. Carbon deposits can also be caused by aromatic hydrocarbons in fuel, metals in fuel, additives in fuel, stop and go traffic, short trips, high load low revving engines, and emission control systems. What does this look like in an intake valve? Look at these pictures:

The result of this carbon build up within a vehicle’s systems can vary depending on many factors in an engine’s design, but generally, drivers will notice sluggish performance, rough running, poor emissions, a drop in fuel economy, and in extreme cases, engine damage. Gasoline Direct Injection (GDI) engines have been found to be prone to early carbon build up. Frequent short trips and stop and go travel have caused noticeable carbon buildup in these engines – even before the first oil change.


This is an intake valve from a Ford Escape 2.0 Ecoboost GDI Engine with 8,656 miles.  This vehicle was in the repair facility for its first oil change.


To keep any vehicle running like it did when it left the factory, proper maintenance at regular intervals is key. This is especially true when interacting with today’s new technology. Proper oil change intervals are critical in maintaining performance and fuel economy.  All of the vehicle today have two mileage recommendations found in the owner’s manual – schedule 1 and schedule 2, described as normal and severe drivers/conditions. These are important to note.  Following these recommendations will lead directly to satisfied, happy customers with reliable vehicles. Ignoring these recommendations will lead to many of the problems listed above.  

Many of the carbon problems addressed here can be avoided before they even begin with proper maintenance. Proper maintenance is simply following basic interval recommendations with quality products.  If a driver extends intervals or chooses lower quality products, he/she is gambling with their engines performance, fuel economy, and longevity.  

For best care and proper maintenance, start by changing the vehicle’s oil with a quality oil and adding BG MOA to ensure the oil is protecting the system for the entire interval. Then, use quality fuel system cleaners like our BG 44K for the life of the vehicle. Finally, follow up with induction and injection cleaning by a qualified technician at recommended intervals. Your customer will be happy you did.



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