Multi-Port Fuel Injection (MFI) System

GM’s Vortec engines come with a Sequential Port Injection System (SCPI). Our Multi-Port Fuel Injection (MFI) system has several advantages over the original Sequential Central Port Injection (SCPI) system, including port fuel delivery and high reliability, better hot starts and reduced vapor emissions, and faster prime on hot restarts.

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Improved hot fuel handling over SCPI system
Lack of poppet valve eliminates problem of deposit build-up
Improved spray injector nozzle design with longer seat and no valvet ball reduces deposit buildup that can cause clogs
Enhanced pressure control at low recirculation rates

The above Multi-Port Fuel Injector is also available for the GM V8.

Tech Tip: For successful installation, lubricate injector tips and O-ring seals with transmission assembly gel, petroleum jelly, or even clean engine oil. Do not use silicone.

NAPA Echlin's MFI Advantages

Built to last up to 10 yrs/100,000 miles – an improvement over the SCPI system
Advanced pulse-to-pulse precision, low voltage performance at open throttle
Improved sealing over SCPI system
Better transient response over SCPI system
Low vacuum sensitivity
Low heat transfer to fuel
Faster temperature stabilization over SCPI system
Low heat transfer to fuel tank

How to Replace a Multi-Port Fuel Injector

Replacing the multi-port fuel injection (MFI) system on a GM V6 4.3L engine is a complicated job. Our ASE-certified master technician shows you how it's done: