INTRODUCTION
This video will summarise the most important operating concepts of a modern gasoline injection system. Learning the operating principles of an EFI system will better prepare you to troubleshoot this type of fuel system. when servicing is required. This program will also enable you to observe the many different components that make up an electronic fuel injection system. You will learn about the basic operation, function, and design of an electric fuel pump, a throttle body, a fuel rail assembly, an injector, several types of engine sensors, and much more. You will also discover subsystems, such as a fuel return system and an engine air supply system which contribute to the quality performance of a modern fuel injection system. This tape provides you with the knowledge needed to comprehend the operations of present-day EFI systems. Use this film as a reference when diagnosing problems in this particular type of fuel supply system
Copyright 1992, Meridian Education Corporation

STUDENT OBJECTIVES
After viewing this video, the student will be able to:
Name several advantages a gasoline injection system has over a carburettor system.
Explain the function of a fuel supply system.
Describe the purpose of a fuel filter and fuel strainer.
Explain the construction and operation of two types of in-tank electric fuel pumps.
Describe the operation and function of a fuel gauge sending unit
Explain the purpose of a fuel return system.
Describe the operation and purpose of a fuel rail assembly.
Explain the operation of a modern electronic fuel injector.
List the parts of single-point and multi-point gasoline injection systems.
Describe the components and operations of a computer controlled gasoline injection system.
TO THE INSTRUCTOR
This video is designed to be a valuable supplement to your curriculum. Since young people are extremely acclimated to television, it is a natural way to help present important aspects of your subject matter. This video is designed to give a detailed, yet broad coverage of the topic.
Most educators agree that it is best to use as many instructional methods as possible. Utilise quality textbooks, workbooks, videos, lectures, demonstrations, overheads, and other methods to present the technical information. This will hold interest and help pupils understand the large amount of information required to succeed in today's complex world.
This video is organised into major sections or topics. Each section covers one major segment of the subject. Graphic breaks are given between each section so that you can stop the video for class discussion, demonstrations, to answer questions, or to ask questions. This allows you to only watch a portion of the program each day or to present the complete video, depending on your curriculum requirements.

VIDEO QUIZ
Choose the most correct answer after reading the statement:
1. The fuel supply system must force fuel from the fuel tank through fuel lines and to the ___________________ .
a. pump b. engine c. compressor d. head
2. A fuel ___________________ keeps dirt, rust, and other particles in the fuel tank from entering the fuel pump, lines, and injectors.
a. hose b. plug c. strainer d. vent
3. Today's trend is to use a(n)___________________ in-tank electric fuel pump on most automotive gasoline injection systems.
a. aluminium b. plastic c. brass d. single
4. A ____________________ is often used to control the electric fuel pump on modem gasoline injection systems.
a. diode b. computer c. resistor d. capacitor
5. The fuel ______________________ assembly is a thick hollow tube or fuel manifold for distributing gasoline to each of the injectors.
a. rail b. line c. filter d. valve
6. Where does the fuel pressure regulator normally mount on a TBI system?
a. Under the dash b. In the trunk c. On top of the throttle body assembly d. None of the above
7. A modem electronic fuel ________________ is simply an electrically operated fuel valve.
a. filter b injector c. pump' d. regulator
8. The throttle body on a multi-point injection system only controls and carries _______________________ .
a. air b. fuel c. oxygen d. propane
9. A ___________________ is needed to prevent a vacuum leak between the idle air control valve assembly and the throttle body housing.
a. plate b. hose c. bolt d. gasket
10. If the oxygen sensor detects too much unburned fuel in the engine's exhaust, it tells the computer to _________________ the pulse width.
a. lengthen b. shorten c. increase d. expand
11. If the oxygen sensor detects a too lean exhaust, it tells the computer to ____________________ the pulse width.
a. lengthen b. shorten c. decrease d. determine
12. When in ________________________ loop, a computer controlled injection system operates without feedback from the oxygen sensor. a. closed b. starting c. ignition d. open
13. When the engine warms, a computer controlled injection system goes into __________________ loop and reacts to signals from the oxygen sensor .
a. closed b. starting c. ignition d. open
14. The ____________________ sensor can adjust fuel metering depending on the amount of load or power output placed upon the engine a. temperature b. MAP c. MOP d. airflow
15. The ______________ sensor measures the amount of air flowing into the engine .
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The video is designed to simplify the complex. Concise wording and carefully selected graphics are used to provide maximum learning in minimum time.
Close-up shots of components and service procedures are used to make every second of viewing instructional, as if each student was standing right behind you, watching over your shoulder while you were working or giving a demonstration.
Computer animation is used to explain difficult to comprehend principles or techniques. These images show how parts work, how they fit together, or how they vary in design.
QUIZ ANSWER KEY
1.b 2.c 3.d 4.b 5.a 6.c 7.b 8.a 9.d 10.b 11.a 12.d 13.a 14.b 15.c
Use your own judgement to evaluate the definitions, short answer questions and discussion topics.
TECHNICAL TERMS
Write definitions for the following terms. Use a textbook or review the video if needed.
electronic gasoline injection system I electric fuel pump solenoid-type injectors I computer control system I intake manifold carburettor I air-fuel mixture I fuel delivery system I fuel filter fuel strainer I in-tank electric fuel pump I fuel gauge sending unit single pump electronic fuel injection system I centrifugal force non-positive displacement fuel pump I roller vane electric fuel pump fuel return system I fuel rail assembly I fuel rail service fitting fuel pressure gauge I injector tester I injector cleaner I TBI assembly fuel pressure regulator I throttle body injection I throttle body multi-point injection system I idle control system I MAP sensor idle air control valve I engine air supply system I oxygen sensor single-stage throttle body I two-stage throttle body I airflow sensor throttle sensor I open loop I closed loop I engine temperature sensor

VIDEO DISCUSSION TOPICS
Here are a few topics that might be used for a class discussion:
1. Which is easier to service, a gasoline injection fuel system or a carburettor fuel system?
2. Why were two electric fuel pumps used in early model fuel injection systems?
3. What prevents an in-tank electric fuel pump from igniting the gasoline in the fuel tank?
4. Describe how a fuel gauge sending unit operates.
5. What is the purpose of a service fitting on a fuel rail?
6. Explain how a fuel pressure regulator works.
7. Name some of the engine sensors used to operate an electronic fuel injection system.
8. Why is engine vacuum sometimes used in automotive computer systems to detect engine operating conditions?

SHORT ANSWER
Briefly answer the following questions in your own words:
1. Why is a gasoline injection system generally considered more dependable than a carburetor fuel system?
2. Does a gasoline injection system normally contain a fuel filter?
3. Name some of the functions of the computer in a computer controlled gasoline injection system.
4. Describe the operations of a "roller vane" electric fuel pump.
5. Explain the function of a "fuel return system."
6. What is the purpose of a fuel pressure regulator in a gasoline injection system?
7. Describe the construction of a typical fuel injector.
8. Explain the term "TBI assembly. "
9. What is the difference between a "single-point" injection system and a "multi-point" injection system.
10. Define the term "injector pulse width. "
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WE NEED YOUR HELP!
We are constantly trying to improve our videos. If you have any suggestions or comments, please send them to us with details (title, time code location, etc.) of any potential improvement. We will try to incorporate suggestions when revising our videos. Your help will be greatly appreciated. We want to help you train America's youth!
OTHER TIMELY TOPICS on
AUTOMOTIVE ELECTRICAL SYSTEMS available from :
MERIDIAN EDUCATION CORPORATION
Starting System Service (Item No.5167)
Starting System Operation (Item No.5166)
Ignition System Operation (Item No.5170)
Ignition System Service (Item No.5171)
Charging System Operation (Item No.5168)
Charging System Service (Item No.5169)