CC: Chances are in the next few months you will be hearing a lot about E-15 summer blend fuels making their way to pump in April. E-15 use more ethanol in it blend to reduce our dependence on fossil fuels. No matter your politics, you must wonder what this means for engines and in particular the spark plugs. The reality is that most drivers don’t have to worry. These engines are calibrated from the OE manufacturer to change fuel and spark based on inputs from a fuel sensor. There is no special spark plug or gap recommendation for vehicles using the E-10, E-15 or E-85 Ethanol blends that are offered in the USA.
These vehicles have no modifications to their fuel or ignition systems and therefore they should be serviced as if they were running on gasoline only. However, E-85 can only be used in designated Flex Fuel engines. The exception to this is when a factory gasoline fueled engine has been converted to E-85 to support modifications to increase power output. In these engines, the spark plug should be one to two heat ranges colder depending on the level of modification.
No matter the fuel blends or percentage of ethanol, a worn-out spark plug will have problems igniting the fuel inside the combustion chamber. This is why you need to look up the recommended replacement interval for the customer’s vehicle and replace them before they become a problem.
This video is sponsored by Autolite.