Automotive computer and Fuel system
Fuel pressure for a gasoline injection system is normally at__.
15-40 psi.
The typical reference voltage fed to sensors is ____ volts.
5
If the noid light does not flash when checking an electronic fuel injector's feed circuit,the cause of the problem may be all of the following except:
A faulty injector.
To dampen pressure pulses in an injection system, a fuel ____ can be used.
Accumulator
A(n) ____ dagnostic test uses the scan tool to order the computer to energizes specific output devices.
Actuator
In a diesel engine, ___ is compressed until it becomes hot enough to ignite the fuel.
Air
Check amount of air entering engine.
Air flow sensor
which of the following is an advantage of gasoline injection over carburetor system?
All of above(better atomization of the fuel,better fuel distribution,increase engine power).
To keep fuel from sloshing across the tank when the vehicle is in motion, most tanks are equipped with ____.
Bluffer
A pressure gauge connected to the fuel pressure test fitting(schrader valve)shows a pressure lower than spec.Technician A says that the low pressure is likely to be caused by a faulty fuel pressure regulator.Technician B says that the fuel pump is possibly at fault.Who is correct?
Both A and B.
Technician A says that a passive sensor can be tested by applying a reference voltage and measuring the voltage drop across the sensor. Technician B says that a passive sensor can be tested by using an ohmmeter to measure its internal resistance. Who is correct?
Both A and B.
Which of the following is not a component of mechanical fuel pump?
Bowl fuel filter.
When a(n) _____ fuel injection system is used, fuel is being injected whenever the engine is running.
CIS
On newer vehicles,a flashing malfunction indicator light warns of a problem that could damage the____.
Catalytic converter
Trouble codes set by an OBD I system can be read manually by each of the following methods, except:
Counting beeps of the vehicle's horn.
Detect engine speed.
Crankshaft position sensor
_____ values produced by a vehicle's computer give electrical operating values of sensors, actuators, and circuits.
Data stream
On-off signals from engine sensors are called ____ signals.
Digital
Open injector
Doesn't spray fuel
Some scan too cartridges can be updated by______new information from a computer.
Downloading
A mechanical fuel pump is usually powered by a(n) ____ on the camshaft.
Eccetric
A(n) _____ fuel pump is usually located in the main fuel line or in the fuel tank.
Electric
Measures engine coolant temperature.
Engine coolant temperature sensor
Alcohol fuel made from farm crop.
Ethanol
A clicking sound from an injector indicates that it is a faulty and should be replaced.
False
EFI tester are designed to be used for checking almost any make of vehicle.
False
Gasohol is usually a blend of 20 percent alcohol and 80 percent gasoline.
False
In a diesel engine,fuel is injected at the end of the compression stroke
False
Light blows of a hammer can be used to seat a new TBI injector.
False
Most electric fuel pumps are of the reciprocating type.
False
Pinpoint tests are wiring checks that are done by piercing wires with sharply pointed meter probes.
False
Plastic lines made of high-strength nylon tubing are used in some fuel system
False
Typical output of an oxygen sensor is 0.5 volts.
False
Vacuum rather than pressure,is the actuating force behind fuel injection system.
False
most paper air filter element can be clenned and reused at least once.
False
tetraethyl lead still widely used as anti-knock additives in gasoline.
False
Mixture of gasoline and alcohol.
Gasohol
Problem in which the circuit has a fixed valve,no output,or an output that is out of specification.
General circuit failure
Problem that does not come and go with varying conditions.
Hard failure
The _____ pipe carries exhaust gases from the exhaust manifold to the catatlytic converter.
Header
The exhaust manifold ____ valve aids starting in cold weather.
Heat
The ____ rating of a gasoline measures its ability to resist knock and ping.
High Octain
Problem that produces a voltage,current,or signal frequency above normal operating parameters.
High-input failure
In a TBI system, fuel is sprayed into the top of the air ____.
Horn
Highly flammable gas.
Hydrogen
The___is not one of the subsystem of an electronic fuel injection system.
Idle solenoid system.
Problem that involves a sensor producing values slightly higher or lower than normal.
Improper range/performance failure
A rich fuel mixture will ____ fuel consumption.
Increase
Which method of EEPROM programming involves the use of a scan tool?
Indirect program.
Measure temperature of air entering the engine.
Intake air temperature sensor
A(n) _____ fuel injection system opens and closes injectors independently of the engine's intake valves.
Intermittent
A dual exhaust system is most common on___engine.
Large engine.
Alternate fuel often used in industrial engine.
Liquefied petroleum gas
Problem that produce a voltage ,current,or signal frequency below normal operation parameters.
Low-imput failure
Dirty injector
Makes fuel mixture too lean.
Leaking injector
Makes fuel mixture too rich
Measures vacuum at engine intake.
Manifold absolute pressure (MAP) sensor
All of the following are active sensors, except:
Mass airflow sensor.
Electronic _____ injection systems use one injector for each engine cylinder.
Multipoint
Before servicing some EFI systems, you must disconnect the ____ battery terminal.
Negative
Technician A says the ideal ,chemically correct fuel mixture is 14 parts air to 1 part fuel.Technician B says that 15 air to 1 part fuel is the right ratio.Who is correct?
Neither.
A(n) ____ switch will turn off the electric fuel pump in the event of a collision.
Neutral
The most common fuel for automotive diesel engines is ___ diesel oil.
No. 2
A special test light designed for checking EFI feed circuits is called a(n) ____ light.
Noid
The on-board diagnostic system in older vehicle is referred to as __.
OBD I
A(n) _____ can be used to check the operation of EFI engine sensors; so can a test light or a digital meter.
Ohmmeter
A switching sensor can be checked for proper operation with a(n)____.
Ohmmeter.
Vehicles equipped with ____ systems can set trouble codes that pinpoint injector problems.
On board Diagnostic
For system using a carburetor,fuel pump volume output should be approximately___in 30 sec.
One pint.
An active sensor generates its own ____ .
Output voltage
Checks exhaust gas for combustion efficiency.
Oxygen sensor
_____ numbers identify the location and purpose of each terminal in a computer wiring harness connector.
Pin
Preignition will cause____in the engine.
Ping.
Which of the following is not a common method used to control fuel injection system?
Pneumatic system.
Modern scan tools provide step-by-step instruction called___.
Prompts
A throttle position sensor should produce specific _____ readings at various throttle openings.
RPM
An integrated junction block holds most or all of the vehicle's mechanical ____ in a single housing.
Relay
The catalytic converter is designed to ___.
Remove pollutants from the engine's exhaust.
A knock sensor tells the computer to ____ the timing if the engine starts to knock.
Retard
Impeller, roller vane, and sliding vane fuel pumps are all ____ types.
Rotary
The wiring diagram or _____ for the computer system is found in a shop manual.
Schematic
Using an incorrect ______ can poison an oxygen sensor.
Sealant
Heat ______ must always be replaced after exhaust system repairs.
Sheild
Problem that occurs on intermittently.
Soft failure
An OBDII system will identify problems with all the components listed, except:
Starter Solenoid.
When checking a multiport injection system, a(n) ____ weill help you verify the operation of individual injectors.
Stethoscope
The perfect air-fuel ratio for combustion in an engine is called a(n) ____ fuel mixture.
Stoichio metric
A(n) ____sensor acts as either a conductor or insulator.
Switching
Fuel made from coal or tar sand.
Synthetic fuel
Technician A says that wearing an anti-static wrist strap is an effective means of preventing damage when working on computer circuits. Technician B says that disconnecting the vehicle's battery is sufficient. Who is correct?
Technician A.
Technician A says that both OBD I and OBD II systems will pinpoint a sensor that is operating poorly or incorrectly. Technician B says that OBD I will only indicate that a circuit is no longer operating properly. Who is correct?
Technician B.
A cold-start injector is active by a(n)__.
Thermo-time switch
Monitor throttle plate shaft rotation.
Throttle position sensor
Key-on/engine-off diagnostics allow the technician to check for___.
Trouble codes
OBD II requires manufactures to use a set of standardized
Trouble codes
A lean air-fuel mixture result in poor gas mileage.
True
A modern scan tool allows the technician to monitor operating conditions while performing a test drive
True
A nick or dent in a turbocharger can cause severe vibration.
True
A scan tool is now the most important tool of automobile technician.
True
A throttle positioner is used to control high-speed operation.
True
All vehicles with 16-pin data link connectors are OBD II compliant.
True
Diesel fuel does not vaporize as easily as gasoline.
True
Disconnecting computer wiring with the ignition key on can cause damage to the computer.
True
EEPROM chips are usually soldered to the computer's circuit board. They are not removable.
True
Fuel pressure in an injection system can be high as 40 psi.
True
Fuel tanks should be emptied before dismounting from the vehicle for service.
True
In CIS injection system,the injection deliver fuels intermittently .
True
In a sequential fuel injection system,the injectors open one after the other,instead of all at one time.
True
In an air induction system,flow of air into the engine is controlled by throttle valve.
True
In an direct injection system,the fuel is forced into the combustion chamber itself.
True
OBD II requires all automotive manufactures to use a set of standardized trouble codes.
True
One reason for a poor injector spray pattern is a dirty nozzle.
True
Since they have moving contact points, relays are often a source of computer system problems.
True
To test an EFI system,an oscilloscope can sometimes be used.
True
Vacuum leaks can affect the operation of a vehicle's computer system
True
Water and acid in engine exhaust can cause exhaust system to parts to fail in a fairly short time.
True
Without a scan tool, it is not possible to recover trouble codes from an OBD II system.
True
once an engine stop running,pressure in the EFI system is automatically relieved.
True
problem with clogged fuel filter are most apparent at higher speed.
True
Before testing or servicing any system, the technician should ____ the problem to be sure it is described accurately.
Verify
On turbocharger,the___prevents producing too much pressure in the combustion chambers.
Waste gate.
You should never try to _____ a fuel tank, since an explosion could result.
Weld on
Loose dirty,or corroded electrical connections often can be found by using a(n)_____test
Wiggle
The fuel return system helps ____ the fuel to prevent vapor lock.
cool
After system repairs are made, trouble codes should be _____ to prevent a possible misdiagnosis by the next technician to work on the vehicle.
erased
Each of the following is a type of supercharge,except:
reciprocating.
A faulty fuel tank ____ unit can make the fuel gauge reading inaccurate.
sending
Mechanical fuel pumps usually must be replaced,rather than service,when defective.
true
The data link connector for an OBD II system most often will be located:
under the dash or center console, near the driver's seat.
