Chapter 10 PowerPoint Presentation AE&E

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

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.

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

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

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

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

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

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.)

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

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

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

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

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.”

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

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

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

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

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

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

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

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

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

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.)

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

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

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).

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

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

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

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

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

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.)

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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.

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.

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.

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).

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.

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.

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.

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.

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.