Modern fuel injection systems require high pressure, most of the time between 40-60 psi. You can't supply this by holding a can of gasoline above your car. Here's some math: pressure in pascals = p (density of the fuel) * g (force of gravity) * h (height in meters)

p = 719kg/m³

g = 9.81m²

So if you hold a can of gas 1 meter above your car you will get: 719 * 9.81 * 1 = 7053.39 pa = 1.023psi

You get 1 psi per meter you raise the fuel, so to get enough to start your car you'll need to raise the fuel 45 meters up, about a 15 story building.

Yes you can gravity feed your fuel system - but you will need 45 meters of high pressure fuel line and a 15 story building to do it.

Modern fuel injection systems require high pressure, most of the time between 40-60 psi. You can't supply this by holding a can of gasoline above your car. Here's some math: pressure in pascals = p (density of the fuel) * g (force of gravity) * h (height in meters)

p = 719kg/m³

g = 9.81m²

So if you hold a can of gas 1 meter above your car you will get: 719 * 9.81 * 1 = 7053.39 pa = 1.023psi

You get 1 psi per meter you raise the fuel, so to get enough pressure by gravity alone to start your car you'll need to raise the fuel 45 meters up, about a 15 story building.