1. Chapter 10 PowerPoint Presentation AE&E

2. Chapter 10 PowerPoint Presentation AE&E
Fuel and Emission Control Systems Electronics Service

3. Chapter 10 PowerPoint Presentation AE&E
Objectives
Recall the tasks involved in a preliminary inspection of the injection system.
Test electrical/electronic components found on late-model fuel and emission control systems.
Use a fuel system wiring diagram to locate all the components in the circuit that could be causing problems.

4. Chapter 10 PowerPoint Presentation AE&E
Objectives
Summarize OBD II monitoring features used on late-model fuel injection and emission control systems.

5. Fuel Injection Electronics Service
Chapter 10 PowerPoint Presentation AE&E
Fuel Injection Electronics Service
Fuel injection is controlled electronically
Electric fuel pumps
Sensors
Electronic control units
Fuel metering keeps each cylinder at maximum efficiency

6. Injection System Inspection
Chapter 10 PowerPoint Presentation AE&E
Injection System Inspection
Check condition of all system components
Look and smell for fuel leaks
Listen for vacuum leaks
Check terminals of wiring harness

7. Fuel System On-Board Diagnostics
Chapter 10 PowerPoint Presentation AE&E
Fuel System On-Board Diagnostics
Self-diagnostic mode
Trouble codes in older systems
Compare to charts in service manual
Scan tool

8. OBD II Fuel System Monitoring
Chapter 10 PowerPoint Presentation AE&E
OBD II Fuel System Monitoring
Feedback from primary oxygen sensor controls fuel mixture
Adjustments
Short term fuel trim
Long term fuel trim

9. Injector Noid Light Test
Chapter 10 PowerPoint Presentation AE&E
Injector Noid Light Test
Disconnect wiring harness
Fit noid light into harness connector
Start engine and check light
Repeat on all nonworking injectors
(OTC/SPX Corp.)

10. Chapter 10 PowerPoint Presentation AE&E
Injector Balance Test
Connect pressure gauge to test fitting
Close fuel volume measurement valve
Connect balance tester to injector
Turn ignition key on to pressurize system
Turn ignition key off
Press tester button

11. Injector Balance Test (Cont.)
Chapter 10 PowerPoint Presentation AE&E
Injector Balance Test (Cont.)
Watch pressure gauge drop
Record pressure drop reading
Repeat for other injectors
Compare injector readings

12. Injector Balance Test (Cont.)
Chapter 10 PowerPoint Presentation AE&E
Injector Balance Test (Cont.)
(Chevrolet)

13. Fuel System Wiring Diagrams
Chapter 10 PowerPoint Presentation AE&E
Fuel System Wiring Diagrams
Show all components in circuit
Consult if you have difficulty finding problem

14. Chapter 10 PowerPoint Presentation AE&E
Review
In general, how can you tell if a vacuum hose has a leak?
Answer: Listen for the characteristic “hiss.”

15. Chapter 10 PowerPoint Presentation AE&E
Review
The temporary adjustment of injector pulse width to correct the fuel mixture is referred to as short term _____.
Answer: fuel trim

16. Chapter 10 PowerPoint Presentation AE&E
Injector Problems
Bad injector
Shorted or open coil windings
Injector or engine misfire trouble code
Leaking injector
Worn or dirty injector
Weak or broken return spring

17. Injector Problems (Cont.)
Chapter 10 PowerPoint Presentation AE&E
Injector Problems (Cont.)
Dirty injector
Lean air-fuel ratio
Poor spray pattern
Inadequate fuel delivery

18. Servicing EFI Injectors
Chapter 10 PowerPoint Presentation AE&E
Servicing EFI Injectors
Check with stethoscope
Check coil condition (engine off)
Measure resistance across injector coil
Check wiring to injector
Check supply voltage to injector

19. Replacing Multi-Point Injectors
Chapter 10 PowerPoint Presentation AE&E
Replacing Multi-Point Injectors
Bleed off fuel system pressure
Remove hose from injector and fuel rail
Unplug electrical connection
Remove injector
Inspect rubber parts
Replace injector and rubber parts, if necessary

20. Replacing Multi-Point Injectors (Cont.)
Chapter 10 PowerPoint Presentation AE&E
Replacing Multi-Point Injectors (Cont.)
(Ford)

21. Fuel Tank Sending Unit Service
Chapter 10 PowerPoint Presentation AE&E
Fuel Tank Sending Unit Service
Test fuel gauge before sending unit
Use ohmmeter to test sending unit
For further testing, remove sending unit
Measure resistance
Check float for leakage

22. Fuel Tank Sending Unit Service (Cont.)
Chapter 10 PowerPoint Presentation AE&E
Fuel Tank Sending Unit Service (Cont.)
(Honda Motor Co.)

23. Chapter 10 PowerPoint Presentation AE&E
Fuel Pump Service
Low fuel pump pressure
Worn pump bearings
High resistance in pump circuit
Leaking check valves
High fuel pump pressure
Inoperative pressure relief valve
Faulty fuel pressure regulator

24. Electric Fuel Pump Circuit Tests
Chapter 10 PowerPoint Presentation AE&E
Electric Fuel Pump Circuit Tests
Perform pressure and volume tests
Measure voltage to pump motor
(Honda Motor Co.)

25. Chapter 10 PowerPoint Presentation AE&E
Fuel Pressure Sensor
Monitors fuel pressure
Measures fuel temperature
Read trouble code on scan tool

26. Fuel Pump Shutoff Circuits
Chapter 10 PowerPoint Presentation AE&E
Fuel Pump Shutoff Circuits
Inertia switch
Blocks fuel flow after impact
Oil pressure switch
Shuts off fuel pump if oil pressure is low

27. Chapter 10 PowerPoint Presentation AE&E
Review
While using a stethoscope to check an EFI injector, you hear a clicking sound. What does this mean?
Answer: The injector is working (opening and closing).

28. Chapter 10 PowerPoint Presentation AE&E
Review
What type of switch is used to block current flow to the electric fuel pump after a collision?
Answer: inertia switch

29. Emission Control System Electronics Service
Chapter 10 PowerPoint Presentation AE&E
Emission Control System Electronics Service
Defects in computer-controlled parts
EGR valve
Evaporative emission purge valve
Air injection
Other components
OBD II

30. Emission Maintenance Reminder
Chapter 10 PowerPoint Presentation AE&E
Emission Maintenance Reminder
Dash light reminder for emission control service
Must be deactivated after adjustments and repairs are done
Numerous methods
Refer to service manual

31. Chapter 10 PowerPoint Presentation AE&E
OBD II Monitoring
Evaporative emissions system
EGR
Air injection system
Oxygen sensor
Catalyst monitor

32. Emission System Scanning
Chapter 10 PowerPoint Presentation AE&E
Emission System Scanning
Scan tool monitoring of various emission control systems
Connect scan tool
Check for stored trouble codes
Think about what could cause codes

33. Inspecting Emission Control Systems
Chapter 10 PowerPoint Presentation AE&E
Inspecting Emission Control Systems
Inspect engine vacuum hoses and wires
Listening devices
Piece of vacuum hose
Stethoscope without metal probe
(Snap-on Tool Corp.)

34. Inspecting Emission Control Systems (Cont.)
Chapter 10 PowerPoint Presentation AE&E
Inspecting Emission Control Systems (Cont.)
Look for oil leaks onto oxygen sensor
Check for dirty engine oil and blowby
Inspect air cleaner
Check adjustment of air pump belt

35. Vacuum Solenoid Service
Chapter 10 PowerPoint Presentation AE&E
Vacuum Solenoid Service
Refer to vacuum hose diagram
Check for
Hard, brittle hoses
Voltage to vacuum
Check solenoid valve operation

36. Evaporative Emissions Control System Service
Chapter 10 PowerPoint Presentation AE&E
Evaporative Emissions Control System Service
Evaporative emissions system purge test
Evaporative emissions system pressure test
Evaporative emissions control system maintenance
Replace filter
Inspect fuel tank filler cap and hoses

37. Evaporative Emissions Control System Service (Cont.)
Chapter 10 PowerPoint Presentation AE&E
Evaporative Emissions Control System Service (Cont.)
(Honda Motor Co.)

38. Chapter 10 PowerPoint Presentation AE&E
Review
Another name for the secondary oxygen sensor is _____.
A. elemental sensor
B. catalyst monitor
C. front sensor
D. primary sensor
Answer: B. catalyst monitor

39. Chapter 10 PowerPoint Presentation AE&E
Review
Which test measures the flow of fuel vapors into the engine?
Answer: evaporative emissions system purge test

40. EGR System Electronic Service
Chapter 10 PowerPoint Presentation AE&E
EGR System Electronic Service
EGR valve sticks open
Engine stalling at idle
Rough idle
EGR valve fails to open
Detonation
Knocking

41. Electronic EGR System Testing
Chapter 10 PowerPoint Presentation AE&E
Electronic EGR System Testing
EGR valves trip trouble code
Use scan tool or refer to shop manual
Use oscilloscope to pinpoint trouble

42. Electronic EGR System Testing (Cont.)
Chapter 10 PowerPoint Presentation AE&E
Electronic EGR System Testing (Cont.)
(Fluke)

43. Electric PCV Valve Service
Chapter 10 PowerPoint Presentation AE&E
Electric PCV Valve Service
New versions are electric
Older valves are spring loaded
Use scan tool to locate problems

44. Chapter 10 PowerPoint Presentation AE&E
Testing the MAP Sensor
(Fluke)

45. Testing the MAP Sensor (Cont.)
Chapter 10 PowerPoint Presentation AE&E
Testing the MAP Sensor (Cont.)
Digital MAP Signal
(Fluke)

46. Testing the MAP Sensor (Cont.)
Chapter 10 PowerPoint Presentation AE&E
Testing the MAP Sensor (Cont.)
Analog MAP Signal
(Fluke)

47. Chapter 10 PowerPoint Presentation AE&E
Oxygen Sensor Service
Check during engine rev and deceleration
Lazy O2 sensor
Dead O2 sensor
Replace sensor at periodic intervals

48. Testing Oxygen Sensors
Chapter 10 PowerPoint Presentation AE&E
Testing Oxygen Sensors
(Fluke)

49. Testing Wide Band Oxygen Sensors
Chapter 10 PowerPoint Presentation AE&E
Testing Wide Band Oxygen Sensors
Also called air-fuel ratio sensor
3.3 volts is normal
Other voltages result in trouble code
Scan tool
Oxygen sensor signal generator

50. Chapter 10 PowerPoint Presentation AE&E
Emissions Testing
Emissions testing program
Inspection and maintenance programs
Exact procedures vary from state to state

51. Chapter 10 PowerPoint Presentation AE&E
Review
What symptoms might indicate that an EGR valve is stuck shut?
Answer: detonating or knocking

52. Chapter 10 PowerPoint Presentation AE&E
Review
A(n) _____ oxygen sensor is one that does not alter its output signal fast enough to maintain an efficient air-fuel ratio.
Answer: lazy

53. Chapter 10 PowerPoint Presentation AE&E
Glossary
Catalyst monitor
An oxygen sensor that is located after the catalytic converter. It checks the oxygen content of the exhaust gases after exiting the catalytic converter to determine if the catalyst elements are working. Also called secondary oxygen sensor or rear oxygen sensor.

54. Chapter 10 PowerPoint Presentation AE&E
Glossary
Emission maintenance reminder
A circuit that automatically turns on a dash light to indicate the need for emission control system service. Some vehicles use a mechanical flag that is located inside the speedometer cluster.
Emission system scanning
Involves using a scan tool to check the condition of monitored parts of the various emission control systems.

55. Chapter 10 PowerPoint Presentation AE&E
Glossary
Emissions testing program
A program that involves taking exhaust gas readings as a vehicle’s engine operates at idle and at a set rpm. It may also involve checking the vehicle for the presence of a catalytic converter and a fuel inlet restrictor. Also called an inspection and maintenance program.

56. Chapter 10 PowerPoint Presentation AE&E
Glossary
Evaporative emissions system pressure test
A test that checks the emission system for leaks into the atmosphere. The pressure test equipment is connected to the evaporative emission system’s vapor vent line. A computer then meters low pressure nitrogen into the system (evaporative emission system, fuel lines, fuel tank, and filler neck).

57. Chapter 10 PowerPoint Presentation AE&E
Glossary
Evaporative emissions system purge test
A test that measures the flow of fuel vapors into the engine.
Fuel system monitoring
Involves checking whether a stoichiometric, or theoretically perfect, fuel mixture is being fed to the engine.

58. Chapter 10 PowerPoint Presentation AE&E
Glossary
Injector balance test
A common test performed on modern multi-point or direct electronic fuel injection systems. It involves the use of a fuel injector tester, or EFI analyzer, to measure the amount of fuel flowing through each injector. It will tell you if any injectors are clogged, cracked, shorted, or not opening fully.

59. Chapter 10 PowerPoint Presentation AE&E
Glossary
Inspection and maintenance program
A program that involves taking exhaust gas readings as a vehicle’s engine operates at idle and at a set rpm. It may also involve checking the vehicle for the presence of a catalytic converter and a fuel inlet restrictor. Also called an emissions testing program.

60. Chapter 10 PowerPoint Presentation AE&E
Glossary
Long term fuel trim
A permanent adjustment of injector pulse width to compensate for altered operating parameters.
Noid light
A test light that is used to check electronic fuel injector feed circuits.
Oxygen sensor signal generator
A tool used to send a false 200 mV to 700 mV signal to the computer for testing purposes.

61. Chapter 10 PowerPoint Presentation AE&E
Glossary
Short term fuel trim
Refers to the temporary adjustment of injector pulse width to correct the fuel mixture.