Engine Performance 2
An oxygen sensor is being tested using a digital storage oscilloscope (DSO). A good oxygen sensor should display how many transitions (switches) per second?
1 to 5
A wide-band oxygen sensor needs to be heated to what operating temperature?
1,400°F (760°C)
If the air-fuel ratio is 14.7:1, what is Lambda?
1.0
A wide-band oxygen sensor is capable of detecting the air-fuel mixture in the exhaust from ____________ (rich) to ____________ (lean).
10:1; 23:1
A wide-band oxygen sensor was first used on a Honda in what model year?
1992
The air at high altitude has _____________________.
21% oxygen
The fuel pump inside the fuel tank on a vehicle equipped with gasoline direct injection produces about what fuel pressure?
50 to 60 psi
The fuel injectors used on a gasoline direct injection system are pulsed on using what voltage?
50 to 90
The fuel injectors operate under a fuel pressure of about ________.
500 to 2,900 psi
An ECT sensor reads about 3,000 ohms when tested using a DMM. This resistance represents a temperature of about ________.
70°F (20°C)
A wide-band oxygen sensor heater could draw how much current (amperes)?
8 to 10 A
What is not required to reprogram a vehicles engine control module?
A manufacturer's scan tool
How was programming updated before 1996?
A replaceable PROM was used.
Which method can be used to reprogram an engine control module?
Any of the above
What electronic control module is used to control the shifting of an electronically-controlled automatic transmission/transaxle?
Any of the above depending on application
Where is the fuel-pressure regulator located on a vacuum-biased port fuel-injection system?
At the outlet of the fuel rail
A P0133 DTC is being discussed. Technician A says that a defective heater circuit could be the cause. Technician B says that a contaminated sensor could be the cause. Which technician is correct?
Both Technicians A and B
Technician A says that carbon inside the engine can cause excessive NOx to form. Technician B says that excessive NOx could be caused by a cooling system fault causing the engine to operate too hot. Which technician is correct?
Both Technicians A and B
Technician A says that the fuel pump relay is usually controlled by the PCM. Technician B says that a TBI injector squirts fuel above the throttle above the throttle plate. Which technician is correct?
Both Technicians A and B
Which exhaust gas indicates efficiency? (The higher the level of this gas, the more efficient the engine operates.)
CO2
Which gas is generally considered to be the rich indicator? (The higher the level of this gas, the richer the air-fuel mixture.)
CO2
What is not true about short-term fuel trim?
Can add or subtract a large amount of fuel
What does the electronic pressure control (EPC) solenoid use to control mainline pressure?
Current
When testing an ECT sensor on a vehicle, a digital multimeter can be used and the signal wires back probed. What setting should the technician use to test the sensor?
DC volts
If the transmission fluid temperature (TFT) sensor indicates cold automatic transmission fluid temperature, what would the PCM do to the shifts?
Delayed shift points and torque converter clutch disabled
Where is the fuel injected in an engine equipped with gasoline direct injection?
Directly into the combustion chamber
The sensor that most determines fuel delivery when a fuel injected engine is first started is the ________.
ECT sensor
Which type of port fuel-injection system uses a fuel temperature and/or fuel-pressure sensor?
Electronic returnless systems
What type of sensor measure speed?
Frequency generator
All of the gases are measured in percentages except ______________.
HC
An ignition fault could cause excessive ________ exhaust emissions.
HC
What happens to the voltage measured at the ECT sensor when the thermostat opens?
Increases slightly
Why is a special battery charger specified when programming?
Must use a battery charger that produces little, if any, voltage fluctuations
A clogged EGR passage could cause excessive _________ exhaust emissions.
NOx
What type of sensor is the transmission fluid temperature (TFT) sensor?
Negative temperature coefficient (NTC) thermistor
Which gas is generally considered to be the lean indicator? (The higher the level of this gas, the leaner the air-fuel mixture.)
O2
When testing the ECT sensor with the connector disconnected, the technician should select what position on the DMM?
Ohms
What does a pass-through device do?
Passes data between the Internet and the computer used to program a vehicle
Why are some fuel rails rectangular in shape?
Reduces noise
What organization created the J2534 standard?
SAE
Which fuel-injection system uses the MAP sensor as the primary sensor to determine the base pulse width?
Speed density
What type of device is used in a typical idle air control?
Stepper motor
Which mode of operation results in a richer air-fuel mixture near the spark plug?
Stratified
Which sensor has the greatest influence on injector pulse width besides the MAF sensor?
TP
An oxygen sensor is being tested with a digital multimeter (DMM), using the MIN/MAX function. The readings are: minimum = 78 mV; maximum = 932 mV; average = 442 mV. Technician A says that the engine is operating correctly. Technician B says that the oxygen sensor is skewed too rich. Which technician is correct?
Technician A only
Technician A says that high HC emission levels are often caused by a fault in the ignition system. Technician B says that high CO2 emissions are usually caused by a richer-than-normal air-fuel mixture. Which technician is correct.
Technician A only
Technician A says that reprogramming an engine control module using the J2534 system requires a factory scan tool. Technician B says that reprogramming an engine control module using the J2534 system requires Internet access. Which technician is correct?
Technician B only
Technician A says that the port fuel injection injectors operate using five volts from the computer. Technician B says that sequential fuel injectors all use a different wire color on the injectors. Which technician is correct?
Technician B only
Two technicians are discussing a stepped ECT circuit. Technician A says that the sensor used for a stepped circuit is different than one used in a non-stepped circuit. Technician B says that a stepped ECT circuit uses different internal resistance inside the PCM. Which technician is correct?
Technician B only
Two technicians are discussing the IAT sensor. Technician A says that the IAT sensor is more important to the operation of the engine (higher authority) than the ECT sensor. Technician B says that the PCM will add fuel if the IAT indicates that the incoming air temperature is cold. Which technician is correct?
Technician B only
A transmission control module (TCM) has just been replaced. Which parameters should be programmed into the TCM using a scan tool?
Tire size
Why is a vacuum line attached to a fuel-pressure regulator on many port-fuel-injected engines?
To create an equal pressure drop across the injectors
After the following exhaust emissions were measured, how was the engine operating?
Too rich
Why does the PCM monitor engine oil temperature on some vehicles?
Used to calculate engine oil life
The injectors on an EFI equipped engine are opened using _____________ to lift the spray needle.
a solenoid
The MAF sensor may give an inaccurate measurement if the ____________ is modified.
air inlet system
SAE J2534 is a mandated specification to all automakers who sell vehicles in the United States after 2004 to ____________.
all of the above
The transmission range (TR) switch is used to_________________.
all of the above
Linear solenoids are used for_________________.
all of the above depending on application
The high-pressure fuel pressure is regulated by using _________________.
an electric pressure-control valve
An exhaust gas recirculation (EGR) temperature sensor is used on_______.
both a and b
The catalytic converter is most efficient when the air-fuel mixture is_______
both a and b
Aftermarket programmers may create an issue of ____________
both a and c
A lack of power from an engine equipped with gasoline direct injection could be due to ___________.
both b and c
A low O2S voltage could be due to a ____________.
both b and c
Base pulse width is determined by _________________.
both b and c
If Lambda is 0.98, this means the ___________________.
both b and c
All of the following are advantages of gasoline direct injection except_______.
decreased throttle response
All of the following are disadvantages of gasoline direct injection except _____.
less need for extra fuel for acceleration
A battery maintainer is used during reprogramming to ____________.
make sure the system voltage does not drop during the reprogramming event
Injector pulse width is measured in ____________.
milliseconds (mS)
The voltage output of a zirconia oxygen sensor when the exhaust stream is lean (excess oxygen) is____________.
relatively low (close to 0 volt)
A high O2S voltage could be due to a ____________.
rich exhaust
HC and CO are high and CO2 and O2 are low. This could be caused by a _______________.
rich mixture
A Nissan is being checked, using a scan tool and Alpha is 107. This means _________.
the PCM is adding fuel
The high-pressure fuel pumps used in gasoline direct injection (GDI) systems are powered by ______.
the camshaft
Adaptive control means__________________
the change in the pressure or timing to keep the shift occurring at the same time to make up for wear
A contaminated or defective MAF sensor is indicated if ____________________.
the fuel trim number follows the airflow
The input speed sensor is also called a/an ________.
turbine speed sensor (TSS)
The output speed sensor is also called a/an_________________.
vehicle speed (VS) sensor
