FUEL INJECTION SYSTEM OPERATION CBC AUTO FUEL INJECTION

FUEL INJECTION SYSTEM OPERATION CBC AUTO

FUEL INJECTION TYPES l THROTTLE BODY INJECTION (TBI) – INJECTED ABOVE THROTTLE PLATES – SINGLE INJECTOR l CENTRAL PORT INJECTION (CFI) – INJECTED ABOVE THROTTLE PLATES – USUALLY MORE THAN ONE INJECTOR l PORT FUEL INJECTION (PFI) – INJECTORS IN INTAKE RUNNERS CBC AUTO

TBI UNIT (SOMETIMES CALLED CFI) l l l FIRST STEP FROM CARBURETORS SOME CARB CHARACTERISTICS LOW PRESSURE MOVEABLE PINTLE PRESSURE IS REGULATED SERVICEABLE FIG 6 -40 CLASS CBC AUTO

LOW PRESSURE SYSTEM CBC AUTO

FUEL INLET AND OUTLET CBC AUTO

LOW PRESSURE FUEL INJECTOR l l l 13 -16 PSI TWO O-RINGS BALL PINTLE USED ON TBI AND CFI SYSTEMS MESH SCREEN EASY TO REPLACE CBC AUTO

TWO INJECTOR SYSTEM CBC AUTO

l PORT FUEL INJECTION l l INJECTS AT EACH CYLINDER HIGHER PRESSURE FED OFF OF FUEL RAIL MORE EFFICIENT OPERATION MODES – MULTI-PORT – SEQUENTIAL CBC AUTO

PORT FUEL INJECTION CBC AUTO

CENTRAL POINT INJECTION l l GM SYSTEM INJECTOR LOCATED IN LOWER HALF OF INTAKE MANIFOLD POPPET VALVES HIGH PRESSURE 60 PSI CBC AUTO

CONTINUOUS INJECTION l l SPRAYS ALL THE TIME MIXTURE CONTROL UNIT FUEL DISTRIBUTOR CONTROL PRESSURE REGULATOR CBC AUTO

FUEL PRESSURE REGULATOR l l l Used on TBI systems Provides constant fuel supply Fuel pressure on one side Fuel pressure opens regulator under a certain pressure. Spring is calibrated CBC AUTO

INJECTION SYSTEM SERVICE CBC AUTO

SYSTEM CHECKS ADEQUATE AIR SUPPLY l PRESSURIZED FUEL SUPPLY l ADEQUATE TRIGGER SIGNAL l NO VACUUM LEAKS l GOOD IGNITION SYSTEM l GOOD ENGINE MECHANICAL l GOOD FUEL QUALITY l PCM OPERATION l CBC AUTO

FUEL DELIVERY l l Fuel Pump noises Does fuel pump run at all? Fuel filter condition? Connections to fuel pump CBC AUTO

COMPONENT CHECKS l l l l AIR INDUCTION AIR FLOW SENSORS THROTTLE BODY FUEL SYSTEM CHECKS FUEL DELIVERY INJECTOR CHECKS INJECTOR CLEANING 6 -61 LAB CBC AUTO

INERTIA SWITCH CBC AUTO

INJECTOR TESTS l ELECTRICAL OPERATION – VOLTAGE SIGNALS – SCOPE TESTING l MECHANICIAL OPERATION – PINTLE OPERATION – BALANCE TEST – FLOW CBC AUTO