PFI stands for port fuel injection. It operates at relatively low pressure, spraying atomized gasoline into the intake manifold runners where it mixes with incoming air before entering the combustion chamber. The continuous spray of fuel cleans the back of the intake valves, preventing the heavy carbon buildup commonly seen in direct-injected engines.
We're swapping the old throttle body setup for a sequential PFI manifold to get better throttle response.
Also heard as
- port fuel injection
- multi-port injection
Do not mix it up with
- GDI: GDI sprays fuel directly into the cylinder at high pressure, whereas PFI sprays it into the intake port at lower pressure.
Related terms
EFI
Electronic Fuel Injection is a computer-controlled system that atomizes fuel into the engine.
GDI
Gasoline Direct Injection is a fuel delivery system that sprays gasoline directly into the combustion chamber.
Throttle body
A housing containing a pivoting valve that controls the amount of air entering a fuel-injected engine.
Intake manifold
The engine component that distributes incoming air or air-fuel mixture evenly to each cylinder.