Diesels must use glow plugs to warm the fuel when it’s cold due to not having spark plugs. In a way they are quite similar because they both have internal combustion that turn fuel into energy that creates power that makes your wheels turn. But the way the combustion happens is two different methods. In a gasoline engine the fuel is mixed with the air filling the head making the piston compress, then being ignited by spark from the spark plugs. In diesels air is brought in first because when it is compressed it heats up, then the fuel is injected, and when the fuel hits the hot air it ignites. The injection process for these motors are also completely different. Gasolines mostly have carbureted fuel systems which transfer gas from the gas tank through a fuel line into a mechanical fuel distributor called a carburetor, then gets pushed through small injectors called jets that spray fuel directly into the cylinder heads. Diesels all have direct injectors where the fuel is brought from the fuel tank through fuel lines and runs through an injection lift pump that forces high pressure fuel through straight injectors into the cylinder heads. The fuels are also completely different in the ways they are made, smell, feel, evaporation points and their