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Engine Performance 1 Flashcards | StudBud
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Engine Performance 1
Engine Performance 1
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Questions
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Answers
1
What could cause the following readings: Bank 1 long-term fuel trim: -18, bank 2 LTFT: -19?
A defective fuel pressure regulator
A restricted fuel return line
Neither A nor B
Both A and B
2
The secondary circuit of the ignition system produces...
High voltage in the thousands of volts
Dangerously high amperage
Only enough voltage to jump the spark gap
Low voltage
3
What would happen if one ignition coil in this system were to fail?
Misfire on one cylinder only
Nothing the others would compensate
Two cylinders would be affected
The vehicle would not start
4
Tech A says a digital voltmeter CANNOT be used to check a O2sensor. B says a test light CAN be used to check an O2sensor
Neither A nor B
Both A and B
Tech B
Tech A
5
Refer to the illustration. All of the following conditions could reduce engine power during a boost condition EXCEPT:
A leak between the turbocharger and the exhaust manifold
Damaged compressor fins
A blown gauge fuse
Wastegate valve stuck open
6
A stuck open fuel pressure regulator would cause high fuel pressure readings.
True
False
7
Coolant temperature input is used to determine open and closed loop status.
True
False
8
How does a wastegate on a turbocharged engine control boost pressure?
It closes to allow exhaust gasses to bypass the turbine
It blocks all exhaust gasses from the turbine until boost is needed
It opens to allow an ammount exhaust gasses to bypass the turbine
It opens to relive excess boost pressure in the in the intake manifold
9
Tech A says a stethoscope can be used to pinpoint engine noises. Tech B says a long screwdriver can be used for this.
A only
Both A and B
B only
Neither A nor B
10
A restricted exhaust can cause all of the following EXCEPT:
Reduced fuel economy
None of the above
Reduced engine efficiency
Unusual noises
11
When completing monitor readiness, the vehicle must be driven under specific conditions in order for the monitors to run
True
False
12
A vehicle with the ignition system illustrated has a no-spark condition on cylinders #1 and #5. What could be the cause?
A faulty crankshaft sensor
A bad coil driver
Fouled sparkplug on cylinder one
PCM failure
13
High system voltage will increase fuel injector on time (pulse width).
False
True
14
A damaged or missing air filter can increase wear on cylinder walls.
False
True
15
On some vehicles the PCM controls ignition timing at all times.
True
False
16
All of the following are possible causes of turbocharger failure EXCEPT:
Poor engine oil maintenance
Poor intake filtration
Poor exhaust system maintenance
Poor engine cooling system maintenance
17
All of the following are components of the primary (low voltage) circuit EXCEPT:
Spark plug wire
Ignition switch
Battery
Ignition coil
18
A clogged fuel filter may affect volume of fuel output while not necessarily affecting the fuel pressure.
True
False
19
A scan tool can be used to look TPS DTCs but you will need an oscilloscope to verify TPS input.
False
True
20
All of the following could cause premature turbo bearing failure EXCEPT
Oil contamination from turbo boost buildup in the engine
Oil contamination from infrequent oil changes
Low oil pressure
Restricted oil passages to the turbo
21
What kind of ignition system is illustrated?
Distributor
Distributorless
Coil on Plug
Waste Spark
22
What causes the MIL (malfunction indicator light) to illuminate?
High coolant temperatures
Low tire pressure
Low oil pressure
Emissions faults
23
If a lean condition is detected what will happen to the short-term fuel trim?
The STFT will not be affected but the LTFT will show a positive value
The STFT will show a positive value
The STFT will not be affected but the LTFT will show negative value
The STFT will show a negative value
24
What is the purpose of secondary air injection?
To lean out the air fuel mixture
To further oxidize hydrocarbon and carbon monoxide emissions in the exhaust
To cool down the exhaust gasses
To trick the O2 sensor into thinking that the emissions are within spec
25
Cranking the engine with the throttle fully depressed will result in the vehicle starting in what mode of operation?
Acceleration
Clear flood
Starting
Run
26
An air filter problem will have no effect on fuel consumption.
True
False
27
Which of these could be a cause of rough idle?
A defective downstream oxygen sensor
An open in the neutral safety switch circuit
Thermostat that is stuck open
Gum and carbon build up in the intake manifold
28
The ignition control module uses a digital signal from the PCM (powertrain control module) for what purpose?
Timing Control
Synchronization Signal
RPM signal
Cylinder ID
29
The cause of a MIL not illuminating during check when the ignition is turned on can be all of the following EXCEPT:
A blown bulb
An internal circuit problem with the PCM
A DTC stored within the PCM
An open MIL circuit
30
What will the PCM do if there is no oxygen detected in the exhaust?
Put the vehicle in limp-in mode
Increase injector pulse width
None of the above
Decrease injector pulse width
31
A DTC will tell you all of the following information EXCEPT:
Which circuit is affected
Which component is malfunctioning
Which system is affected
None of the above
32
An evaporative system DTC may be set by all of the following EXCEPT:
A loose gas cap
A cracked vacuum hose
An open purge control solenoid
A leaking fuel injector
33
All vehicles require a functional camshaft position sensor to start.
False
True
34
An ammeter is used on the ignition primary circuit to check what?
Polarity
Voltage
Current Draw
Resistance
35
Nylon fuel lines should be inspected for all of the following EXCEPT:
Loose fitting
Kinks
Discoloration
Cracks
36
Special adapters are needed to use a scan tool on OBD-I vehicles but the port for OBD-II vehicles is standardized.
False
True
37
Which of the following computer sensor signals is not used during open-loop mode?
Throttle position sensor (TPS)
Engine coolant temperature sensor
Heated O2 sensor
Manifold absolute pressure (MAP) sensor
38
A cylinder-power balance test on a distributor-ignition vehicle can indicate all of the following problems EXCEPT:
Blown head gasket
Burnt valve
Cracked piston
Weak ignition coil
39
The ignition module controls the timing at startup on some vehicles.
True
False
40
A SFI vehicle stalls intermitently at idle and shows a negative LTFT value All of the following could cause this EXCEPT:
Leaking fuel injectors
A vacuum leak
A leaking fuel pressure regulator diaphragm
A fuel pressure regulator stuck closed
41
All of the following are inputs for electronic timing control EXCEPT:
Oxygen sensor
Knock sensor
Engine coolant temperature sensor
Throttle position sensor (TPS)
42
Throttle body cleaner can be used on all makes and models.
True
False
43
When an emissions related fault is detected all of the following will occur EXCEPT:
The malfuntion indicator light (MIL) will illuminate
The ECM will advance spark timing to compensate
Freeze frame data will be stored
None of the above
44
Tech A says the first step in diagnosis is to verify the complaint. B says one of the first steps is a visual inspection
B only
Neither A nor B
A only
Both A and B
45
All of the following could cause a multiple-cylinder misfire code EXCEPT:
R*tarded valve timing
A burnt valve
A leaking EGR valve
Low fuel pressure
46
It is standard practice on late model vehicles to remove the negative battery cable for five seconds to clear DTCs.
True
False
47
All of the following components are part of the fuel pump control circuit EXCEPT:
Ignition switch
Body Control Module (BCM)
Fuel pump relay
Powertrain control module (PCM)
48
Which of the follow diagnostic trouble codes are Type A codes and should be troubleshot first?
Non-emissions related
Vehicle speed control
Transmission
Misfire control
49
A soft code in the PCM memory is a code that:
Idicates a top priority code
Exists at the time the vehicle is being tested
Can be found if a diagnostic flow chart is used
Occurred in the past but no longer exists
50
How can you check thermostat operation?
By letting the car run for five minutes and then removing the radiator cap
By feeling the hoses to see if they're hot
With a scan tool and a thermometer
Visually by running the vehicle from cold to hot and watching its operation
51
Which of the following is the LEAST LIKELY cause of a fuel tank leak?
Faulty retaining straps
Rust
Leaking tank seams
Road damage
52
What could cause a single cylinder misfire DTC?
Low battery voltage
Low fuel pump pressure
A bad ignition coil
A thermostat that's stuck closed
53
Techn A says freeze frame data is always set for a misfire code. Tech B says a misfire code is a high-priority code.
Both A and B
Tech B
Neither A nor B
Tech A
54
What might cause a misfire on only one cylinder?
Both A and B
Neither A nor B
An open spark plug wire
High fuel pump pressure
55
All of the following are part of the diagnostic process EXCEPT:
Re-flash the PCM
Verify the complaint
Road test the vehicle
Perform a visual inspection
56
In order for readiness monitors to run the system that is being monitored must not have any related DTCs stored
False
True
57
It is standard practice to run the monitor for the repaired system before returning the vehicle to the customer.
True
False
58
Which of the following is the first noticeable symptom of a restricted air filter?
A no-start condition
Excessive oil consumption
Loss of power
Decrease in fuel economy
59
A vehicle has a DTC for an open vehicle speed sensor circuit. Which of the following would most likely be affected?
Manual transmission shift points
Cruise control system
Traction control system
Air conditioning (A/C) system
60
A short-term fuel trim of 0 percent and a long-term fuel trim of +19 percent means what?
The engine has a history of running rich
The engine is running rich at the present time
The engine is running lean at the present time
The engine has a history of running lean
