1. FUEL INJECTION SYSTEM OPERATION
CHAPTER 11

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

3. TBI UNIT (SOMETIMES CALLED CFI)
FIRST STEP FROM CARBURETORS
SOME CARB CHARACTERISTICS
LOW PRESSURE
MOVEABLE PINTLE
PRESSURE IS REGULATED
SERVICEABLE
FIG CLASS

4. LOW PRESSURE SYSTEM

5. FUEL INLET AND OUTLET

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

7. TWO INJECTOR SYSTEM

8. PORT FUEL INJECTION INJECTS AT EACH CYLINDER HIGHER PRESSURE
FED OFF OF FUEL RAIL
MORE EFFICIENT OPERATION
MODES
MULTI-PORT
SEQUENTIAL
PORT FUEL INJECTION

9. PORT FUEL INJECTION

10. CENTRAL POINT INJECTION
GM SYSTEM
INJECTOR LOCATED IN LOWER HALF OF INTAKE MANIFOLD
POPPET VALVES
HIGH PRESSURE 60 PSI
FIG 6-49 CLASS

11. CONTINUOUS INJECTION SPRAYS ALL THE TIME MIXTURE CONTROL UNIT
FUEL DISTRIBUTOR
CONTROL PRESSURE REGULATOR

12. 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

13. INJECTION SYSTEM SERVICE
CHAPTER 6
LAB MANUAL

14. 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

15. FUEL DELIVERY Fuel Pump noises Does fuel pump run at all?
Fuel filter condition?
Connections to fuel pump

16. COMPONENT CHECKS AIR INDUCTION AIR FLOW SENSORS THROTTLE BODY
FUEL SYSTEM CHECKS
FUEL DELIVERY
INJECTOR CHECKS
INJECTOR CLEANING
6-61 LAB

17. INERTIA SWITCH

18. INJECTOR TESTS ELECTRICAL OPERATION MECHANICIAL OPERATION
VOLTAGE SIGNALS
SCOPE TESTING
MECHANICIAL OPERATION
PINTLE OPERATION
BALANCE TEST
FLOW