Port injection is a fuel delivery method where injectors are mounted in the intake manifold runners. The fuel mixes with incoming air before passing through the intake valve into the combustion chamber. This design helps wash the back of the intake valves, preventing the carbon buildup commonly seen in direct injection systems.
Heard on the job
We need to clean the injectors on this PI motor because it's idling rough on cold starts.
Also heard as
- PFI
Do not mix it up with
- GDI: PI sprays fuel into the intake manifold, while GDI sprays it directly into the combustion chamber under much higher pressure.
Related terms
GDI
Gasoline Direct Injection is a fuel delivery system that sprays gasoline directly into the combustion chamber.
TBI
Throttle body injection is an early electronic fuel delivery system that sprays fuel centrally before the intake manifold.
EFI
Electronic Fuel Injection is a computer-controlled system that atomizes fuel into the engine.