Adv Diagnosis and Repair
a speed density EFI system computer determines the amount of air entering the engine from the sensor and engine rpm input signals
MAP
if a catalytic convertor in a late model vehicle is not working proper the willl turn on
MIL
hydrocarbons and carbo monoxide exhaust emission are highest when the engine is cold
true
if the IAC pintle is extended too far the motor can be damaged during installation
true
if the PCV valve is stuck in the open position a lean air fuel ratio may cause a rout idle or engine stalling
true
intercoolers are radiator for the intake air
true
never turn on the ignition switch when any fuel system component is disconnected
true
on some models a pop rivet must be removed from the strut mount before a camber adjustment can be made
true
other than inspecting the electrical connections there are usually no physical checks to mass airflow or manifold absolute pressure sensors
true
sai helps the vehicles steering system return to straight ahead after a turn
true
the engine must be at normal operating temperature before the o2 sensor is tested
true
the higher the altitude the lower the atmospheric pressure
true
when performing an alignment the steering angle sensor may require calibrations
true
Diesel engines emit less HC CO and Co2 the spark ignition gasoline engines
true `
Which of the following statements is false?
unequal side to side SAI will not cause a pull while driving
a water manometer for testing crankcase pressure vacuum can be made from a 2 1/2 foot length of
clear plastic tubing
an intercooler can reduce the temperature of the inlet air as much as degrees Fahrenheit
150
Nox emissions are caused by nitrogen and oxygen uniting at cylinder temperatures about
2500
EGR flow is disabled during throttle opening greater than percent
50
while discussing EGR systems with a differential pressure feedback EGR sensor. Tech a says the DPFE sensor sends a signal to the PCM in relation to intake manifold pressure. tech b says the PCM can make correction to the EGR flow if the actual flow does not match the desired flow
B only
when the engine is running at peak efficieny the only gas that is desirable to be at its peak level is
CO2
which of the following is NOT an engine exhaust pollutant that is changed by the catalytic converter
Co2
emissions are caused largely by unburned fuel from the combustion chambers
HC
which of the following is not a comment of a throttle by wire system
IAC motor idle air control
a typical four gas exhaust analyzer does not measure emission
NOx
all of the following are considered harmful gases
O2
the systems removes blobby gases from the crankcase and recirculates them to the engine intake
PCV
only meets the requirements of OBD 11 regulations
SFI sequential fuel injection
to monitor the vapor purge in most systems the PCM changes the duty cycle of the purge solenoid while monitoring the
STFT
which sensor synchronizes the firing of the injectors and determines when piston number 1 is on the compression stroke
a camshaft position sensor
in closed loop the PCM adjusts the pulse width according to inputs fro a variety of sensors but primarily the
a o2s oxygen sensor
a vehicle with excessively high fuel pressure is being diagnosed technician a says the problem could be a restricted fuel return line. technician b says the problem could be a shorted fuel pump relay
a only
after a two wheel alignment the steering wheel on the vehicle is not centered. tech a recommends a four wheel alignment to determine whether the rear wheels are parallel to one another and perpendicular to a common centerline. b says if the steering wheel is not centered after an alignment it should be pulled off the column and correctly positioned
a only
fuel trim is being discussed. technician a says a positive fuel trimp values PCM detects a lean mixture and is increasing the pulse width to add more fuel to the mixture. technician b says LTFT is erased when the ignition is turned off
a only
tech a says the EGR vent solenoid is normally open. tech b says the EGR control solenoid is normally open
a only
tech a says the EVAP monitor for an OBD11 system determines whether there is sufficient purge flow by varying the purge solenoid duty cycle while monitoring change in STFT. tech b says the canister vent solenoid must be open during the EVAP pressure test portion of the monitor
a only
tech a says the main advantage of a turbocharger is that it allows for an increase of power without a substantial decrease in fuel economy. tech b says the use of exhaust gas to drive the turbocharger rob power from the engine when the vehicle is driven at low speed
a only
technician a says an intake manifold vacuum leak may cause high idle speed. technician b days a dirt iac bypass passage will not cause the idle speed to be below specifications
a only
technician a says cross caster is the difference between the left side and right side caster. technician b says excessive negative caster can be corrected by moving the upper ball joint or strut mount
a only
technician a says if the distance between the leading edges of the front tires is less than the distance between the trailing edges there is toe in. technician b says front toe in is adjusted by adding or removing shims between the upper control arms and the body frame
a only
technician a says the engine should idle for 20 to 120 seconds after a hard run to allow the turbocharger shaft to cool tech b says if the vehicle has not been driven for a few days start the engine up and run it at 2000 rpm to flush the old oil out of the turbocharger bearing and oil lines
a only
do not use compressed to flush or clean the fuel rain
air
when cleaning the injectors with a pressurized injector cleaner trio ro starting the engine
all answers are correct
a catalytic converter may be tested with a
all the answers are correct
a cpi fule injection system for a six cylinder engine has
all the answers are correct
an o ring at the base of a fuel injector
all the answers are correct
fuel injectors may be controlled
all the answers are correct
the OBD 11 EGR system monitor tests the function of the EGR system by opening the EGR valve while monitoring the change in
all the answers are correct
unequal SAI Angeles can cause
all the answers are correct
which of the following is a cause of detonation
all the answers are correct
the function of the air bypass valve in a modern supercharger is to
allows the supercharger to idle when extra power is not needed
an exhaust is one of the valuable diagnostic tools for drivability problems
analyzer
a rich air fuel mixture is being discussed. technician a says oxygen content in the exhaust will be high. technician b says the o2 sensor voltage will be hig
b only
tech a says if the EGR valve does not open the engine may meet excessive amounts of HC tech b sys if the EGR valve does not open the ending may detonate on accelation
b only
technician a checks a PCV valve by sucking air through it with his mouth tech b checks a PCV valve by removing the valve from the grommet in the valve cover and placing his finger over the end of the valve to check for vacuum
b only
technician a says a small leak in the air duct between the MAF and the throttle body will not cause a drivability problem. technician b says a small intake manifold leak in a speed density system will not cause a drivability problem
b only
technician a says all vehicles with strut suspension have caster adjustment. technician b says caster is the first angle checked during a two wheel alignment
b only
technician a says if a lean condition caused by a vacuum leak restricted injectors dirty MAF college fuel filter or bacd fuel pump exist the LTFT will have a negative number. technician b says when the o2 sensor has a rich signal the STFT goes lean to adjust the air fuel rato
b only
technician a says if caster at both wheels is not equal the vehicle will tend to drift toward the side with the most positive camber. technician b says if camber is not the same on both wheels the vehicle will put toward the side with the most positive camber
b only
technician a says in a returnees fuel system. the pressure regulator is mounted on the fuel rail. technician b says in a returnees fuel system the pressure regulator fuel sender and pump assembly are combined in one unit inside the fuel tank
b only
technician a says positive caster will result from excessing toe in. technician b says a vehicle may wander s a result of excessive negative caster
b only
technician a says the oxygen sensor detects misfires by monitoring the mount of unburned fuel in the exhaust system. technician b says a heating element inside the sensor allows the sensor to reach operating temperature quickly and to maintain is temperature during periods of idling or low engine loud
b only
technician a says throttle body cleaner may be used to clean the IAC motor internal components Technician b says on some vehicles IAC motor damage can occur if the pintle is cleaned with throttle body cleaner
b only
technician a says when the ECT sensor detect low engine temperature, the PCM decreases the injection pulse width. technician b says when the tp sensor detects a sudden increase in throttle angle the PCM increases the injectors pulse width
b only
variable intake manifolds for engines with port fuel injection are being discussed. tech a says at low speeds the air travels through a short or large diaper runner. tech b says they deliver more power at high speed
b only
while discussing PFI systems. technician a says the PCM provides the proper air fuel ratio by controlling the fuel pressure. technician b says the PCM provides the proper air fuel rate by controlling the injector pulse width
b only
while discussing central port injection. technician a says the poppet nozzles are opened by the computer. technician b says the popper nozzles are opened by fuel pressure
b only
which of the following statements is also
bent suspension parts may be straightened to correct camber angles
excessively high HC emissions may be caused by
both a and b
idle learn procedures for ETC vehicles are being discussed technician a says that learn or relearn procedure should be completed anytime the PCM has been replaced or updated or after the throttle body has been cleaned or replaced. technician b says the system does not need to relearn if the battery has been disconnected. the system will automatically go through the procedure when the engine is restarted
both a and b
tech a says HC emission are caused by incomplete combustion. tech b says an excessively learn air fuel mixture may result in cylinder misfiring and high HC emission
both a and b
tech a says a three way catalytic converter oxidizes carbon monoxide and hydrocarbons into carbon dioxide and water. tech b says a TWC reduces NOx into nitrogen and carbon dioxide
both a and b
tech a says an intake manifold that delivers both air and fuel is designed to cause turbulence so that the air fuel mix while they are being deliver to the cylinder. tech b says in an air only type manifold the length of the runners is designed to achieve the best performance during a particular range of engine speed
both a and b
tech a says cylinder misfiring causes a significant increase in HC emission tech b says a dirty air filter may cause high CO emission s
both a and b
tech a says high engine temperature reduce HC and CO emissions. tech b says incorrect ignition timing can increase the production of NOx
both a and b
tech a says oil in PCV filter and air cleaner can occur if the PCV valve is restricted or plugged. tech b says oil buildup inside the throttle body can be an indication of crankcase pressure
both a and b
tech a says turbocharging uses the heat energy in the engines exhaust gases to drive a pump that compress the intake air. tech b says supercharging relies on the rotation of the engine to compress the air
both a and b
tech a says when CO goes up O2 goes down. Tech b says the stoichiometric point HC CO will be at their lowest levels and CO2 will be at its highest
both a and b
technician a says higher than normal idle speed may be caused by an air conditioning switch the is always closed. technician b says higher than normal idle speed may be caused by defective4 engine coolant temperature sensor
both a and b
technician a says pulsation dampers reduce the pressure pulsations caused by the rapid opening and closing of the fuel injectors. technician b says the damper helps to reduce fuel noise and maintains pressure during engine cool down
both a and b
technician a says the bearing in a turbocharger are cooled by engine oil technician b says turbocharger bearing are cooled by engine coolant
both a and b
technician a says thrust line deviations are usually caused by the shifting of the rear axle on its spring supports. technician b says rear wheel misalignment or damage from an accident can cause throat line deviations
both a and b
technician b says a defective injector may cause cylinder misfiring at idle speed. technician b says restricted injector tips may result in acceleration stumbles
both a and b
tech a says the production of Co2 is directly related to the amount of fuel consumed therefore more fuel efficient engines produce less Co2. tech b says imposing new CAFE standards will in effort reduce Co2 emission
both a or b
is the angle of the steering axis of a wheel fro the vertical as viewed from the side of the vehicle
caster
Nox HC and CO are charged into harmless gases by the in the three way catalytic converter
catalyst
before the EVAP system on an OBD 11 vehicle can be pressure tested or smoke tested for leaks a scan tool must be used to
close the canister vent solenoid
in sequential fuel injection systems each injector has its own electrical circuit ad wiring
driver
the IM 240 test requires the use of a variable intertia weight
dynamometer
the bolt and cam assembly is often used to adjust camber and caster settings
eccentric
a linear EGR valve contains up to three electric solenoid that are operated directly by the PCM
false
aftermarket kits are only used adjuster rear camber and rear toe
false
all EGR valves can be tested with a vacuum gauge while the engine is idling
false
always pressurized the fuel system before disconnecting any fuel system components
false
an ignition misfire can cause excessive carbon monoxide emission in the exhaust
false
because modern engines heat up rapidly heated oxygen sensors are not needed
false
electric turbocharger are standard equipment in some newer vehicles
false
generally an engine designed for maximum torque and horsepower at high speeds has longe runners that one that provides high torque at lower speeds
false
low CO indicates a lean mixture as the mixture becomes more lean HC increases
false
supercharger are normally lubricated by engine oil through passages in the intake manifold
false
the auxiliary air valve is controlled by the PCM
false
the exhaust analyzer used in IM 240 measure the emission levels in ppm
false
the rear axle of and FWD car is the preferred jacking point when the rear wheels need to be removed to make her toe and camber adjustment
false
vacuum refers to any pressure that is higher than the Earths atmospheric pressure at any give altitude
false
when intake air is compressed its temperature decreases significantly
false
when performing a four wheel alignment you should check and adjust the front wheel angles before checking and adjusting the rear wheel angles
false
the injectors on a modern port fuel injection system receive fuel from the
fuel rail
heated air inlet systems manifold heat control valves and EFE heater grids were used on older cars with carburetors and TBI fuel injection to prevent vaporized fuel from considering inside the
intake manifold
the cools the turbocharged air before t reaches the combustion chamber
intercooler
a vehicle is being aligned that has too much positive camber and too little positive caster on the left front wheel. the vehicle has an adjustable strut mount that allows for both caster and camber adjustment in what direction should the mount be moved
inward and rearward
which of the following is NOT a characteristic of a turbocharger
it requires a mechanical connection between the engine and the pressurizing pump
the activity of an 02 sensor is best monitored with a
lab scope
while cranking a fuel injected engine and holding the accelerator to the wide open throttle position the air fuel mixture will be
lean
a pulse injector uses high current to open the injector
modulation
technician a says TBI system use top fuel feeding injectors. technician b says PFI systems use bottom fuel feeding injectors
neither a or b
technician a says a defective throttle position sensor will not affect the EGR valve operation tech b says a defective engine coolant temperature sensor will not affect the EGR valve operation
neither a or b
which of the following sensors is used to modify the engines air fuel mixture based on oxygen in the exhaust
o2 sensor
vacuum leaks in speed density system cab be verified by watching the on a scan tool
o2 sensor cycle
a is used to test the internal electrical circuit of an injector
ohmmeter
boost pressure is measured with a pressure gauge
on a road test at full throttle
the first time the OBD 11 system monitor detects a fault in the system a DTc is set. this will not cause the MIL light illuminate and will self erase if the monitor passes on the next trip
pending
in an intake manifold for a PFI engine the serves as a reservoir for the air and is used to distribute the intake charge evenly to the runners and intake ports
plenum
which problem is not caused by excessive positive caster
poor steering return
the helps to maintain constant fuel pressure reduces fuel noise and maintains pressure during engine cool down
pulsation damper
many vehicles are designed to use of various thickness to adjust camber and caster settings
shims
which of the following should not be used to lubricate o rings
silicone grease
a fuel injection system that uses a MAP sensor to determine the amount of air entering the engine is called a type injection system
speed density
A stuck open EGR valve could cause
stalling
the iac system uses a motor to retract or extend the IAC valve
stepper
which of the following is NOT part of enhanced evaporative control system
thermal vacuum valve
a Digital EGR valve has up to solenoids
three
an APP accelerator pedal position sensor is found on vehicles with
throttle by wire
turning the adjsutment sleeve on the changes the toe setting
tie rod
is the distance comparison between the leading edge and trailing edge of the front tires
toe
is the last alignment angle to be set
toe
a PCV valve that is stuck closed or restricted hose can cause an accumulation of moisture and sludge in the engine
true
a catalytic converter can be tested with a rubber mallet
true
a catalytic converter is one of the most effective control devices on a vehicle for reducing on a vehicle for reducing HC CO NOx emission
true
a digital EGR valve contains up to a three electric solenoids that are operated directly by the PCM
true
a good injector makes a rhythmic clicking sound as the injector is energized and de energized several time each second
true
a three way catalytic converter stores oxygen when the air fuel ratio is rich
true
a twin scroll turbocharger uses two turbine wheels connected to a common shaft to improve performance and reduce lag
true
a vehicle with high caster settings may experience increased shoulder wear on the tires if driven mostly in urban areas
true
an AIR system should be checked for overall efficiency by looking at the changes in exhaust quality when the system is turned on and off
true
an alternative to the IM 240 test is the acceleration simulation mode test
true
an engine in good condition will produce a steady. constant vacuum reading about 15 inches at a warm idle
true
bottom feed injector used in throttle body injection systems are able to use fuel pressure as low as 10psi
true
exhaust manifolds for most vehicles are made of cast or nodular iron
true
fuel injectors are electromechanical devices
true
the is a chart of the vacuum hose routing vacuum source and relative component location for all emission related equipment
vacuum schematic
