engine performance revel
Which item is a computer output device?
Evaporative emission control solenoid
Which is a continuous monitor?
Fuel system monitor
Global (generic) OBD II contains some data in what format?
Hexadecimal
Which type of sensor uses a burn-off circuit?
Hot wire MAF sensor
What happens to the voltage measured at the ECT sensor when the thermostat opens?
Increases slightly
Which of the following is true about the comprehensive component monitor?
It check shorts-to-ground.
A wide-band oxygen sensor has an internally damaged heater circuit. What could this cause?
It may not set a DTC.
Which sensor does the TP sensor backup if the PCM determines that a failure has occurred?
MAF sensor
Which of the following is not a purpose or function of the MAP sensor?
Measures engine speed
Which of the following is a diesel fuel additive?
Microbicide,Multi-functional conditioners,Winter conditioners
When testing the ECT sensor with the connector disconnected, the technician should select what position on the DMM?
Ohms
Which of the following statements is TRUE as an advantage of oxygenated fuels?
Oxygenated fuels are commonly used in high-altitude areas to reduce carbon monoxide (CO) emissions. Correct. The extra oxygen helps ensure there is enough oxygen to convert all CO into CO2during the combustion process.
By looking at the way diagnostic trouble codes are formatted, which DTC could indicate that the gas cap is loose or defective?
P0442
The SAE term for the vehicle computer is
PCM
The ignition module has direct control over the firing of the coil(s) of an electronic ignition system. Which component controls the module?
Pickup coil
A TP sensor is what type of sensor?
Potentiometer
Which of the following parameters does a computer input sensor sense?
RPM
If the MAF sensor fails, the PCM uses ________ to calculate fuel delivery needs.
RPM and throttle position
Which method can be used to reprogram a PCM?
Remote
Which wire on a TP sensor should be back-probed to check the voltage signal to the PCM?
Signal
What part of the scope pattern shows the duration of the spark?
Spark line
Which of the following itself becomes a sensor in an ion-sensing ignition system
Spark plug
What should be inspected as part of a visual inspection of the ignition system?
Spark plug wires for proper routing
The primary (low-voltage) ignition system must be working correctly before any spark occurs from a coil. Which component is not in the primary ignition circuit?
Spark plug wiring
Which sensor is used to measure the position of the throttle?
TP sensor
Most TP sensors have how many wires?
Three
What two things can a vehicle computer actually perform (output)?
Turn something on or turn something off
Because of ________________, an ignition coil cannot be fully charged (reach magnetic saturation) until after a delay of about 10 milliseconds.
inductive reactance
The location of the variable fuel sensor is always in the fuel line between the fuel tank and the fuel
injectors
The four basic computer functions include
input, processing, storage, and output
Reid vapor pressure
is the pressure of the vapor above the fuel when the fuel is at 100°F (38°C).
A spark tester should be used to check for spark because
it can detect a cracked spark plug
Typical primary coil resistance specifications usually range from __________ ohms.
less than 1 to 3
A reluctor is a
notched ring or pointed wheel
Which of the following products are created in the methanol-to-gasoline (MTG) process?
olefins and paraffins (alkenes), and aromatic compounds
The regular diesel fuel is also known as
petrodiesel
When testing a MAP sensor, the technician should first check the ________ voltage.
reference
The voltage output of a zirconia oxygen sensor when the exhaust stream is lean (excess oxygen) is
relatively low (close to 0 volt)
A fuel-injection system that does not use a sensor to measure the amount (or mass) of air entering the engine is usually called a(n) ________ type of system.
speed density
The ideal ratio at which all the fuel combines with all the oxygen in air and burns completely is called the _____________ ratio.
stoichiometric Correct. The ideal ratio is stoichiometric ratio.
A pending code is set when a fault is detected due to
the first fault of a two-trip failure
The preferred method to clear diagnostic trouble codes (DTCs) is to
use a scan tool
Tetraethyl lead (TEL)
was added to gasoline in the early 1920s to reduce the tendency to knock.
A freeze-frame is generated on an OBD-II vehicle
when a type A or B diagnostic trouble code is set
Which is the factory scan tool for Chrysler-brand vehicles equipped with CAN?
wiTECH
Natural gas can be turned into a liquid if cooled to below
−260°F (−162°C).
ll OBD-II vehicles use what type of read-only memory?
EEPROM or E2PROM (electrically erasable programmable read-only memory)
A wide-band oxygen sensor was first used on a Honda in what model year?
1992
OBD II has been on all passenger vehicles in the United States since
1996
The typical MAF reading on a scan tool with the engine at idle speed and normal operating temperature is _____.
3 to 7 grams per second
When checking the ECT sensor with a scan tool, about what temperature should be displayed if the connector is removed from the sensor with the key on, engine off?
40°F (40°C)
The cetane rating of diesel fuel should be between _
45 and 50
Fischer-Tropsch
A _____________ processing plant is able to produce a variety of fuels from coal.
Which of these tools would be used to test a MAP sensor?
A digital voltmeter
A wide-band oxygen sensor is capable of detecting the air-fuel mixture in the exhaust from ______ (rich) to ______ (lean).
10:1 to 23:1
Typical TP sensor voltage at idle is about
0.5 volt or 10% of WOT TP sensor voltage
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
Typical secondary coil resistance specifications usually range from __________ ohms
6,000 to 30,000
A typical IAT or ECT sensor reads about 3,000 ohms when tested using a DMM. This resistance represents a temperature of about ________.
70°F (20°C)
Analog signals from sensors are changed to digital signals for processing by the computer through which type of circuit?
Analog-to-digital convertor
Which statement is false?
Absolute pressure is equal to barometric pressure plus intake manifold vacuum.
Which of the following are considered as biomass?
Agricultural residue and wood waste.
Why is all gasoline said to be fungible?
All gasoline is capable of being interchanged because each grade is created to specification. Correct. Fungible is the ability of the matter to be interchanged.
vehicles have only one fuel tank.
Biodiesel-powered
Technician A says that the first step in the diagnostic process is to verify the problem (concern). Technician B says the second step is to perform a thorough visual inspection. Which technician is correct?
Both Technician A and B
A MAF sensor on a General Motors 3800 V-6 is being tested for contamination. Technician A says that the sensor should show over 100 grams per second on a scan tool display when the accelerator is depressed to WOT on a running engine. Technician B says that the output frequency should exceed 7000 Hz when the accelerator pedal is depressed to WOT on a running engine. Which technician is correct?
Both Technicians A and B
A P0102 DTC is being discussed. Technician A says that a sensor circuit shorted-to-ground can be the cause. Technician B says that an open sensor voltage supply circuit could be the cause. Which technician is correct?
Both Technicians A and B
A P0107 DTC is being discussed. Technician A says that a defective MAP sensor could be the cause. Technician B says that a MAP sensor signal wire shorted-to-ground could be the cause. Which technician is correct?
Both Technicians A and B
Technician A says that a defective spark plug wire or boot can cause an engine misfire. Technician B says that a tracked ignition coil can cause an engine misfire. Which technician is correct?
Both Technicians A and B
Technician A says that if the opposite DTC can be set, the problem is the component itself. Technician B says if the opposite DTC cannot be set, the problem is with the wiring or grounds. Which technician is correct?
Both Technicians A and B
The "brain" of the computer is the
CPU
Which of the following ignition systems or circuits does not require the use of a camshaft position sensor to determine specific cylinder numbers when used in an engine?
Compression-sensing ignition
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
The correct formula for DI is:
DI = 1.5 × T10 + 3 × T50 + T90
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
What is the purpose of the World Wide Fuel Charter?
Develop a quality standard for the kind of gasoline fit to be used
GTL diesel
Diesel fuel created using the Fischer-Tropsch diesel (FTD) process is called _
help prevent power loss and stalling in cold weather.
Diesel fuel heaters
What is another name for waste-spark ignition system?
Distributorless ignition system
During spark knock (detonation) Correct. This happens because the speed of combustion increases.
During which period does the combustion speed to increase by up to 10 times, thus causing increase in temperatures and pressures, which can damage pistons, gaskets, and cylinder heads.
has better cold-flow properties than conventional diesel.
E-diesel
The sensor that most determines fuel delivery when a fuel-injected engine is first started is the
ECT sensor
A technician attaches one lead of a digital voltmeter to the ground terminal of the TP sensor and the other meter lead to the negative terminal of the battery. The ignition is switched to on, engine off and the meter displays 37.3 mV. Technician A says that this is the signal voltage and is a little low. Technician B says that the TP sensor ground circuit has excessive resistance. Which technician is correct?
Neither Technician A nor B
Two technicians are discussing Karman Vortex sensors. Technician A says that they contain a burn-off circuit to keep them clean. Technician B says that they contain a movable vane. Which technician is correct?
Neither Technician A nor B
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 MAP sensors use a 5-volt reference voltage from the PCM. Technician B says that the MAP sensor voltage will be higher at idle at high altitudes compared to when the engine is operating at near sea level. Which technician is correct?
Technician A only
Technician A says that knowing if there are any stored diagnostic trouble codes (DTCs) may be helpful when checking for related technical service bulletins (TSBs). Technician B says that only a factory scan tool should be used to retrieve DTCs. Which technician is corre
Technician A only
Technician A says that reprogramming a PCM using the J2534 system requires a factory scan tool, while Technician B says it requires Internet access. Which technician is correct?
Technician A only
Two technicians are diagnosing a poorly running engine. There are no diagnostic trouble codes. When the MAF sensor is unplugged, the engine runs better. Technician A says that this means that the MAF is supplying incorrect air flow information to the PCM. Technician B says that this indicates that the PCM is defective. Which technician is correct?
Technician A only
A P0118 DTC is being discussed. Technician A says that the ECT sensor could be shorted internally. Technician B says that the signal wire could be open. 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 a 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
After a TP sensor has been tested using the MIN/MAX function on a DMM, a reading of 5 volts is displayed. What does this reading indicate?
The TP sensor signal is shorted to 5-volt reference.
After a TP sensor has been tested using the MIN/MAX function on a DMM, a reading of zero volts is displayed. What does this reading indicate?
The TP sensor was open at one point during the test
anhydrous ethanol
The alcohol product in the dehydration stage is known as
Which item is not important to know before starting the diagnosis of an engine performance problem?
The brand of engine oil used
Which wide-band oxygen sensor incorporates a pump cell?
The dual-cell type
An ignition misfire or fuel mixture problem is an example of what type of DTC?
Type A Correct. Upon detection of a misfire type A (200 revolutions), which causes catalyst damage, the MIL blinks once per second during the actual misfire, and a DTC is stored.
Which of the following statements stands TRUE as the process for reformulating gasoline by gasoline refiners?
Use additives that contain at least 2% oxygen by weight and reduce the additive benzene to a maximum of 1% by volume.
Which can be used to test for a fault with a cylinder on a waste-spark system?
Using short sections of rubber hose attached to the coil terminals
Which step should be performed last when diagnosing an engine performance problem?
Verifying the repair
Name the kind of vehicle where the Powertrain Control Module adjusts the injector pulse-width and the ignition timing to optimize engine operation to the use of E85.
Virtual flexible fuel vehicle
What unit of electricity is used as a signal for a computer?
Volt
Methane
When CNG is processed, 93% of it is
Cracking
________________ is the process where hydrocarbons with higher boiling points could be turned into lower boiling hydrocarbons by treating them at very high temperatures.
A low O2S voltage could be due to
a lean exhaust
A typical MAP compares the vacuum in the intake manifold to
a perfect vacuum
A high O2S voltage could be due to
a rich exhaust
As engine speed increases, the timing of the spark in the cylinder must be
advanced
Cellulose ethanol
can be produced from a wide variety of cellulose biomass feedstock.
Biodiesel has a higher ____________ number than conventional diesel
cetane
Computer speed is measured in
clock speed (Hz)
A COP ignition system can be called all of the following,
coil-by-plug,coil-near-plug,coil-over-plug
As the altitude of the vehicle increases, BARO voltage
decreases
Coil polarity is determined by the
direction of rotation of the coil windings
HEI and EIS are examples of
distributor ignition system
Poor engine performance could be the result of all of the following
distributor ignition with the CMP and CKP not correctly indexed,high-voltage spark leak,defective coil
A P0122 DTC is retrieved using a scan tool. This DTC means
e TP sensor could be shorted-to-ground
A generic (global)-type scan tool can retrieve
emissions-related data
Air that enters the engine without passing through the air flow sensor is called ____________
false air
The oxygen sensor signal is used by the PCM to ______________ the air-fuel mixture.
fine-tune
The computer automatically clears a DTC if there are no additional detected faults after
forty consecutive warm-up cycles
The MAF sensor is used mostly by the PCM to determine the amount of ________ to deliver to the engine.
fuel
DTC P0302 is a(n)
generic DTC
Biodiesel is vegetable oil after the ___________ is removed.
glycerin
Vegetable oil needs to be ________ to obtain a similar viscosity to biodiesel and petroleum diesel.
heated
When the engine is at idle speed, manifold vacuum is
high (17 to 21 in. Hg)
The API viscosity of a diesel fuel is measured using a(n)
hydrometer
As the load on an engine increases, the manifold vacuum decreases and the manifold absolute pressure
increases
