One of the questions I’m asked a lot is whether you can use regular gasoline in a vehicle that was designed for premium. The short answer is no.
The engineers who design engines and their control systems are very careful with the timing of what is called the power stroke.Years ago, when you could tune engines, one of the critical adjustments was ignition timing. Ignition timing, like most other “tuning” tweaks, are no longer adjustable in modern cars.To understand ignition timing, imagine pushing a kid on a swing. The timing of each push is important. If you push too late, you are just pushing air (which can be compared to late or “retarded” timing in an engine). But if you push the kid too early, you will slap his back or maybe push him out of the swing. The perfect timing is to push the child gently in the beginning or forward stroke and continue until the peak of the swinging motion.The same goes for a piston’s power stroke. If it’s too early, the engine “pings” – its version of slap-ping the kid on the back. It will damage an engine.Where does fuel grade fit into this discussion? Well, one of the differ-ences between regular and premium is what is called octane. The higher the octane, the more “con-trolled” it burns. Premium fuel burns more slowly and controlled and is needed in high-performance engines.Newer vehicles have a lot of sensors used to con-trol engine ignition and fuel mixture. Most have what is called a knock sensor, which essentially listens for engine pings and, if it hears them, retards the ignition timing until the pinging stops. But this control has only a small amount of leeway before it can’t adjust the timing anymore, causing the check-engine light to illuminate.
And yes, using the wrong fuel can cause this to happen.
If you find yourself somewhere without access to premium fuel, putting in regular gas will work for a short time. But you would need to accelerate slowly without putting the gas pedal to the floor, and be especially careful not to overwork the engine going over hills or mountains.In the opposite case, don’t use premium gas in a vehicle that calls for regular. It is a waste of money and can decrease mileage.I urge you to always use the manufacturer-recommended fuel grade.