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FUEL INJECTION SYSTEM OPERATION. CHAPTER 11. FUEL INJECTION TYPES . THROTTLE BODY INJECTION (TBI) INJECTED ABOVE THROTTLE PLATES SINGLE INJECTOR CENTRAL PORT INJECTION (CFI) INJECTED ABOVE THROTTLE PLATES USUALLY MORE THAN ONE INJECTOR PORT FUEL INJECTION (PFI)
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FUEL INJECTION SYSTEM OPERATION CHAPTER 11
FUEL INJECTION TYPES • THROTTLE BODY INJECTION (TBI) • INJECTED ABOVE THROTTLE PLATES • SINGLE INJECTOR • CENTRAL PORT INJECTION (CFI) • INJECTED ABOVE THROTTLE PLATES • USUALLY MORE THAN ONE INJECTOR • PORT FUEL INJECTION (PFI) • INJECTORS IN INTAKE RUNNERS
TBI UNIT(SOMETIMES CALLED CFI) • FIRST STEP FROM CARBURETORS • SOME CARB CHARACTERISTICS • LOW PRESSURE • MOVEABLE PINTLE • PRESSURE IS REGULATED • SERVICEABLE FIG 6-40 CLASS
LOW PRESSURE FUEL INJECTOR • 13-16 PSI • TWO O-RINGS • BALL PINTLE • USED ON TBI AND CFI SYSTEMS • MESH SCREEN • EASY TO REPLACE
PORT FUEL INJECTION • INJECTS AT EACH CYLINDER • HIGHER PRESSURE • FED OFF OF FUEL RAIL • MORE EFFICIENT OPERATION • MODES • MULTI-PORT • SEQUENTIAL
CENTRAL POINT INJECTION • GM SYSTEM • INJECTOR LOCATED IN LOWER HALF OF INTAKE MANIFOLD • POPPET VALVES • HIGH PRESSURE 60 PSI FIG 6-49 CLASS
CONTINUOUS INJECTION • SPRAYS ALL THE TIME • MIXTURE CONTROL UNIT • FUEL DISTRIBUTOR • CONTROL PRESSURE REGULATOR
FUEL PRESSURE REGULATOR • Used on TBI systems • Provides constant fuel supply • Fuel pressure on one side • Fuel pressure opens regulator under a certain pressure. • Spring is calibrated
INJECTION SYSTEM SERVICE CHAPTER 6 LAB MANUAL
SYSTEM CHECKS • ADEQUATE AIR SUPPLY • PRESSURIZED FUEL SUPPLY • ADEQUATE TRIGGER SIGNAL • NO VACUUM LEAKS • GOOD IGNITION SYSTEM • GOOD ENGINE MECHANICAL • GOOD FUEL QUALITY • PCM OPERATION
FUEL DELIVERY • Fuel Pump noises • Does fuel pump run at all? • Fuel filter condition? • Connections to fuel pump
COMPONENT CHECKS • AIR INDUCTION • AIR FLOW SENSORS • THROTTLE BODY • FUEL SYSTEM CHECKS • FUEL DELIVERY • INJECTOR CHECKS • INJECTOR CLEANING 6-61 LAB
INJECTOR TESTS • ELECTRICAL OPERATION • VOLTAGE SIGNALS • SCOPE TESTING • MECHANICIAL OPERATION • PINTLE OPERATION • BALANCE TEST • FLOW