Types of Fuel Injectors:

Top-Feed – Fuel enters from the in the top and exits the bottom.

Side-Feed – Fuel enters on the side on the injector fitting inside the fuel rail.

Throttle Body Injectors – (TBI) Located directly in the throttle body.


Types of Fuel Injection Systems:

Throttle body injectors or Single Point Injectors (TBI)
Single-point injection was a first step before the more complex multi-point systems came about. Not as precise as the systems that have evolved, TBI metered fuel better than a carburetor and was less expensive and easier to service.

Port or multi-point fuel injection (MPFI)
Multi-point fuel injection has a separate injector nozzle for each cylinder, just outside its intake port, which is why the system is sometimes called port injection. Delivering the fuel vapor this close to the intake port ensures that it will be drawn completely into the cylinder. The primary advantage is that MPFI meters fuel more precisely than TBI, achieving the desired air/fuel ratio. MPFI lessens the possibility that fuel will condense in the intake manifold.

Sequential fuel injection (SFI)
Sometimes called sequential port fuel injection (SPFI) or timed injection, SFI is a type of multi-port injection. Though basic MPFI uses multiple injectors that spray their fuel at the same time or in groups. Sequential fuel injection triggers each injector nozzle independently and is timed like spark plugs. SFI sprays the fuel immediately before or as the intake valve opens.

Direct injection
Direct injection delivers fuel directly into the combustion chambers, past the valves. More common in diesel engines, direct injection is gaining popularity in gasoline engine designs and is sometimes called DIG or direct injection gasoline. As with other systems, fuel metering is even more precise, and the direct injection gives engineers another variable to influence how combustion occurs in the cylinders.

Fuel injector cleaning and flow testing

Professional Fuel Injection Testing and Cleaning Services for:

Not all are listed, we service fuel injectors for other models too. Call if you have any questions.


Ultrasonic Fuel Injector Cleaner


Fuel Injection Cleaning Specialists


Professional Fuel Injector Cleaning