You may not realize this, that gasoline fuel blends change seasonally. In winter, the gasoline is blended to reduce startup emissions from the tailpipe. In summer, the fuel blends are formulated to reduce evaporative emissions. So how does an engine keep up with these changes? Engines use oxygen sensors and other sensors to make sure the fuel, spark, and combustion event happen at the right time with the same results, no matter the fuel blend. Recently, legislators and environmental regulators have been discussing changes to fuel blends and increasing the amount of ethanol content to 15% for both summer and winter blends. This type of fuel is called E15. Currently, most gasoline at pumps dispensed is 10% ethanol or E10.
What do these changes in ethanol content mean to your customers’ vehicles? On the surface, the change in ethanol content will not change the performance or fuel economy of most engines. Since 2001, E15 has been an approved fuel for vehicles. But those who have not been properly maintained or have issues with injector spray patterns or carbon deposits, well, the increased ethanol content could cause drivability issues, like rough running, misfires, and codes. Vehicles made in the past 21 years can adapt to the changes in fuel formulations. It could be a change to the long-term fuel trims or changes when the spark plug fires. But for these changes to happen, the oxygen sensor must be working as designed. If the oxygen sensor is contaminated with carbon or unburned fuel, the engine might not adapt to the changes in the ethanol content.
Another code that could be set is P0316 for misfires detected during the first 1,000 revolutions. This can be caused by the lack of fuel in the rail or the volatility of the fuel at low and high temperatures. Again, look at the freeze frame information for when this code is set. Code P0316 is typically set when in open loop operation and before the oxygen or air fuel ratio sensor is at operating temperature. It is also a sign that the current conditions do not match the long-term fuel trims. These factors could include poor quality fuel, fuel for the conditions that don’t match. So what’s the cure? Simple, maintenance. Today’s vehicles that may be turbocharged, direct injected, they operate on a very fine line between maximum efficiency and a misfire. Any changes to the inputs, like air, fuel, spark, can cause a misfire and codes. An intake fuel system cleaner can help the engine adapt to these changes in ethanol content by improving the injector spray pattern and cleaning the oxygen sensor. I’m Andrew Markel. Thank you very much.
This video is sponsored by Rislone