Engine Perfomance Final
The term MOST-Likely used to describe a loss of voltage caused when current flows through a resistance is:
Voltage drop
What is a fuel pump?
What is a fuel pump?
How is CO, O2, CO2 measured
%
What type of component is the COP / pen coil?
Actuator
Which of the following exhaust gases is the best indicator of overall engine performance? HC CO CO2 NOx
CO2
Voltage is a measure of
electrical pressure
If the composite vehicle has a‑ coolant temperature of 180 F, what voltage would you expect to see from the ECT?
0.84 volts
In a four cylinder engine, which spark plugs fire at the same time?
1 & 4
What percentage leak is considered good ?
10% (LAB BOOK)
What is the riase time of a good zirconia oxygen sensor?
100 milliseconds
How many coils does the DIS coil pack have for a four cylinder engine?
2
How many spark plugs are connected to one DIS coil in a four cylinder engine?
2 spark plugs can be connected.
At what minimum temperature NOx is produced?
2500 *F
What is the most common reference voltage used with automotive vehicle sensors?
5.00 Volts
What is the typical fuel pressure for a port injected system in a naturally aspirated gasoline four stroke engine?
50 to 60 psi
An oxidizing catalyst starts to work at temperatures between _____ degrees F and __________ degrees F ?
500 to 600 degrees F
Student A says doubling the voltage (for example 12V vs 6V or 24V vs 12V) results in greater circuit current, in order to perform the same amount of Student B says most of the voltage drop in a circuit should take place prior to the load. Which student is correct?
A
While having a discussion, Technician A says that preventing the injection of air into the reduction (NOX) chamber of the cat helps reduce NOX. Technician B says that this has no effect of NOX. Who is correct?
A
An increase in resistance in a circuit (perhaps due to poor connection) would result in:
A decrease in current flow
Technician A said low fuel pressure on a fuel injected vehicle can be caused by a partial or completely clogged fuel filter. Technician B said that high fuel pressure can be caused by a faulty fuel pump.
A is right B is wrong. It caused by a bad fuel pressure regulator
Technician A says modern electronic ignition trigger system can be magnetic AC, Hall effect, or optical sensor. Technician B says all ignition system triggers conduce a square way output signal.
A is true
A cylinder leakage test is a diagnostic procedure that can be used to detect:
Broken piston rings . Leaking cylinder head gaskets Burnt valves
Technician A says that when the oxygen sensor sends a signal that is lower than 0.4 volts, the computer commands the injector to spray more fuel. Technician B says that when the vehicle is under a heavy load the intake manifold vacuum is at maximum (25 inch of Hg) causing the vacuum controlled fuel pressure regular close making less fuel pressure.
A only
What is a drive cycle? A start up and ran cycle that allows the engine to enter closed loop A start up and run cycle where the engine coolant temperature increases by 40 degrees and reached over 160 degrees F. A set of driving conditions that provides enabling criteria for all monitors to run successfully A set of driving conditions that provides enabling criteria for one or more monitors to run successfully
A set of driving conditions that provides enabling criteria for all monitors to run successfully
A trip is: Turning the ignition off and then turning it back on Identical for all vehicles and for all monitors Starting the engine and allowing it to run for 5 minutes in PARK A set of driving conditions that provides enabling criteria for one or more monitors to run successfully
A set of driving conditions that provides enabling criteria for one or more monitors to run successfully
What could cause higher than normal HC? Misfire lean misfire mixture too rich mechanical problem All of the above
All of the above
Which of the following is NOT true of the OBD II Diagnostic Link Connector (DLC)? It has a standardized shape All the terminals in the DLC have a standardized use It has 16 cavities Any OBD II scan tool will connect to it
All the terminals in the DLC have a standardized use
If the secondary ignition signal has no sparkline for one of the cylinders, which of the malfunctions would most likely occure?
An open plug circuit
Technician A says the fuel pressure regulator controlled system minimum and maximum fuel pressure. Technician B says faulty fuel pressure regulator can cause the fuel pressure to go below and above spec
B is correct
When performing a cylinder Balance test, Technician A says you need to turn off one injector at a time and measure the RPM drop of each cylinder. If the RPM does not drop in a specific cylinder, that cylinder has a compression problem. Technician B says the cylinder Balance test is used to identify weak cylinders; it is not used to determine a specific problem. Who is correct?
B only
Technician A says that ignition timing must change as the operating conditions of the engine changes. Technician B says engine speed and engine load are used to determine the amount of timing advance. Who is correct?
BOTH Technician
What are simple methods of determining if a fuel injector is faulty?
By measuring its resistance with an ohmmeter. Listen to the sound an injector makes when the engine is running.
Student A says understanding Kirchhoff's voltage law can save a technician time by not needing to voltage -drop test all parts of a circuit. Student B says a circuit with a poorly performing load may have an open ground connection. Which student is correct?
Both Students are Correct
Students A and B are discussing a 12V series circuit containing a two ohm light bulb and a four ohm light bulb. Student A says the circuit power is 24 watts, and the two ohm light would be the brighter of the two. Student B says the measured current of this circuit could differ substantially from what one might compute. Which student is correct?
Both Students are Correct
Technician A says that the length of time in crankshaft degrees that the primary coil is being charged is the dwell. Technician B says that the dwell time changes with respect to the engine RPM. Who is correct?
Both Technician
Technician A says that excessively high fuel pressure can be caused by a crimped fuel return line. Technician B says that often times engine performance problems are caused by incorrect fuel pressure. Who is correct?
Both Technician A and B
When performing a fuel injector flow test, Technician A says if too much fuel enters the combustion chamber it could cause severe damage to the catalytic converter. Technician B says to be careful when depressing Schrader valves because there will be a certain amount of gasoline spilled when connecting the gauge. Who is correct?
Both Technician A and B
Technician A says that a cylinder can misfire if the injector does not open. Technician B says that a cylinder can misfire if there is low compression in that cylinder. Who is correct?
Both Technicians A and B
Technician A says that a scanner can be used to monitor the output of a sensor. Technician B says that a DVOM can be used to read the output of many sensors. Who is correct?
Both Technicians A and B
Technician A says that incorrect ignition time can cause a misfire. Technician B says that an intake manifold vacuum leak can cause the engine to idle at a higher than normal RPM. Who is correct?
Both Technicians A and B
Technician A says that most TPS and MAP sensors operate on a 5‑volt reference voltage supply from the PCM. Technician B says that analog TPS sensors deliver voltage signals that range from 0.5 volts at idle to 4.5 volts at wide‑open throttle. Who is right?
Both Technicians A and B
Technician A says that the most oxygen sensors have a rise time of 100 ms. Technician B says that a oxygen sensors can be tested using propane. Who is correct?
Both Technicians A and B
While having a discussion about the amount of air entering the engine, Technician A says that as the outside temperature increases more air flow is required for proper combustion. Technician B says as the vehicle get higher in altitude when climbing a mountain, more air flow is needed for proper combustion. Who is correct?
Both Technicians A and B
Technician A says the excessive-high fuel pressure by a crimped fuel return line. Technician B says that oftentimes engine performance problems are caused by incorrect fuel pressure.
Both are right
When performing a fuel injector flow test. Technician A said if too much fuel enters the combustion chamber, it could cause severe damage to the catalyst converter. Technician B said to be careful when depressing the Schrader valve because there could be a certain amount of fuel gasoline spill out.
Both are right
The component is MOST-Likely used to store electricity is the
Capacitor
Engine coolant Temperature (ECT): 230 Deg F 0.35 V Intake Air Temperature (IAT): 66 deg F 3.0 V Mass Airflow Sensor (MAF): 0 gm/sec 0.20 V Throttle Actuator Control Motor (TAC): 0 % Throttle Position Sensor 1 (TP1): 0% 4.50 V Throttle Position Sensor 2 (TP2): 0% 0.50 V Accelerator Pedal Position Sensor 1 (APP1): 0% 0.5V Accelerator Pedal Position Sensor 2 (APP2): 0% 1.50V Crankshaft Position Sensor (CPS): 0 RPM Heated Oxygen Sensor Bank1 (HO2S1/1): 0.0 V Heated Oxygen Sensor Bank2 (HO2S2/1): 0.0 V Heated Oxygen Sensor Post-CAT (HO2S1/2): 0.0V Vehicle Speed Sensor (VSS): 0 mph EVAP Canister Purge Solenoid: 0 % EVAP Canister Vent Solenoid: Off Fuel Pump Relay (FP): On Battery Voltage (B+): 12.3 V Open/Closed Loop: Open Malfunction Indication Lamp (MIL): Off Ignition Timing Advance: 0 BTDC The composite vehicle is difficult to start when cold, runs poorly, and backfires through the intake when trying to accelerate. Once the vehicle is warm, it performs normally. The data in the table was obtained with the key‑on and engine‑off (KOEO) after the vehicle had been outside overnight. How should the technician proceed?
Check the ECT and its circuit.
Engine coolant Temperature (ECT): 209Deg F Intake Air Temperature (IAT): 86 deg F 2.35 V Mass Airflow Sensor (MAF): 0.3 V Throttle Actuator Control Motor (TAC): 21 % Throttle Position Sensor 1 (TP1): 4.25 V Throttle Position Sensor 2 (TP2): 0.88 V Accelerator Pedal Position Sensor 1 (APP1): 5% 0.65 V Accelerator Pedal Position Sensor 2 (APP2): 5% 1.65 V Crankshaft Position Sensor (CPS): 2500 RPM Heated Oxygen Sensor Bank1 (HO2S1/1): 0.89 V Heated Oxygen Sensor Bank2 (HO2S2/1): 0.91 V Heated Oxygen Sensor Post-CAT (HO2S1/2): 0.4 V Battery Voltage (B+): 13.4 V Bank 1 Short Term Fuel Trim (STFT): -13% Bank 2 Short Term Fuel Trim (STFT): -15% MAP/BARO 3.6V The composite vehicle lacks power. The engine has been recently tuned up and results from a power balance test were good. The following snapshot of scan data was captured at 2500 rpm under no-load. Which analysis of this information is correct?
Clogged Catalytic Converter
What are the advantages of a COP / pen coil?
Compact construction. Each COP / pen coil has its own ignition module (output stage) therefore the system is more precisely controlled. The COP / pen coil is connected directly to the spark plug.
What is true about a series circuit
Current is the same in all parts of a series circuitSource voltage equals the sum of all voltage drops Total circuit resistance is equal to the sum of all load resistances
In a four cylinder engine, there's a reluctor with a missing tooth fastened to the crankshaft. When the tooth gap passes the magnetic pickup, the spark plugs of which cylinders spark?
Cylinders 1 and 4.
Which of the following sensors can affect the misfire monitor operation? A) ECT B) Crankshaft PS C) O2 D) All the above
D
Not correct A) cylinder compression reading higher than normal could be cause by excessive carbon in the cylinder B) cylinder compression reading that are within 5% of each other but considerably lower than normal should be cause by a slipping timing chain C) Low cylinder compression reading for 2 cylinders next to each other could be caused by a bad head gasket D) a compression test is best run on a cold engine
D is the false
What action should the PCM take when it receives a high‑voltage signal from the oxygen sensor?
Decrease fuel delivery
Engine coolant Temperature (ECT): 210 Deg F 0.50 V Intake Air Temperature (IAT): 145 deg F 1.45 V Mass Airflow Sensor (MAF): 2 gm/sec 0.07 V Throttle Actuator Control Motor (TAC): 5 % Throttle Position Sensor 1 (TP1): 5% 4.30 V Throttle Position Sensor 2 (TP2): 5% 0.70 V Accelerator Pedal Position Sensor 1 (APP1): 5% 0.65 V Accelerator Pedal Position Sensor 2 (APP2): 5% 1.65 V Crankshaft Position Sensor (CPS): 850 RPM Heated Oxygen Sensor Bank1 (HO2S1/1): 0.01-0.90 V Heated Oxygen Sensor Bank2 (HO2S2/1): 0.01-0.90 V Heated Oxygen Sensor Post-CAT (HO2S1/2): 0.4 V Battery Voltage (B+): 9.4 V EVAP Canister Purge Solenoid: 0 % EVAP Canister Vent Solenoid: Off Fuel Pump Relay (FP): On The composite vehicle will not start. Cranking speed is above 250 rpm. The following PIDs were observed by two technicians under KOEO conditions at closed throttle.
Discharged Battery
Engine coolant Temperature (ECT): 198 Deg F 0.55 V Intake Air Temperature (IAT): 86 deg F 2.35 V Mass Airflow Sensor (MAF): 2 gm/sec 0.2 V Throttle Actuator Control Motor (TAC): 5 % Throttle Position Sensor 1 (TP1): 5% 4.30 V Throttle Position Sensor 2 (TP2): 5% 0.70 V Accelerator Pedal Position Sensor 1 (APP1): 5% 0.65 V Accelerator Pedal Position Sensor 2 (APP2): 5% 1.65 V Crankshaft Position Sensor (CPS): 513 RPM Heated Oxygen Sensor Bank1 (HO2S1/1): 0.78 V Heated Oxygen Sensor Bank2 (HO2S2/1): 0.51 V Heated Oxygen Sensor Post-CAT (HO2S1/2): 0.4 V Battery Voltage (B+): 13.4 V Bank 1 Short Term Fuel Trim (STFT): -12% Bank 2 Short Term Fuel Trim (STFT): -5% EGR Lift: 2.5 V The composite vehicle has an unstable idle, the MIL is on, and DTC P0300 is stored for a Random Misfire. According to the scan data, which of the following could be the root cause of the problem?
EGR valve not seating
What devices or systems use magnetism?
Electromagnets Relays Solenoids Alternators Generators
during a vacuum test, with the engine running, the manifold vacuum dropped after 15 seconds at high cruise and does not increase after the throttle is closed. What is the most likely cause?
Exhaust restriction
Protons are composed of atoms, neutrons, and electrons.
False
During a cylinder compression test, if you hear air coming from the exhaust pipe. What is the most likely cause?
Faulty exhaust valve
The three sections of the secondary ignition signal are:
Firing Section, Intermediate Section, Dwell Section
Which of the following is a Continuous monitor? Fuel Comprehensive components Misfire - everything other than those three is NON-continuous
Fuel Comprehensive components Misfire
In a port injection system, which of the following components are used to deliver fuel or control the amount of fuel sprayed into the engine's combustion chamber?
Fuel Injectors Fuel Pump Oxygen or Air/fuel sensor Load Sensor Camshaft or Crankshaft Position Sensor Engine Coolant Sensor Intake Air Sensor Throttle Position Sensor
Which of the exhaust gas listed below is reduced by catalyst converter? HC CO CO2 ALL HC and CO
HC and CO (also NOx)
The most common electrical fault is
High resistance
Where is the electric fuel pump normally located?
In the fuel tank.
Engine coolant Temperature (ECT): 210 Deg F 0.50 V Intake Air Temperature (IAT): 145 deg F 1.45 V Mass Airflow Sensor (MAF): 2 gm/sec 0.07 V Throttle Actuator Control Motor (TAC): 5 % Throttle Position Sensor 1 (TP1): 5% 4.30 V Throttle Position Sensor 2 (TP2): 5% 0.70 V Accelerator Pedal Position Sensor 1 (APP1): 5% 0.65 V Accelerator Pedal Position Sensor 2 (APP2): 5% 1.65 V Crankshaft Position Sensor (CPS): 850 RPM Heated Oxygen Sensor Bank1 (HO2S1/1): 0.01-0.90 V Heated Oxygen Sensor Bank2 (HO2S2/1): 0.01-0.90 V Heated Oxygen Sensor Post-CAT (HO2S1/2): 0.4 V Battery Voltage (B+): 9.4 V EVAP Canister Purge Solenoid: 0 % EVAP Canister Vent Solenoid: Off Fuel Pump Relay (FP): On The data shown is for a composite vehicle that is exhibiting slow cranking, a hunting idle, and decreased power. What is the MOST likely cause for this condition?
Insufficient output from the charging system
Which of the following is LEAST-Likely a source of emissions?
Intake Plenum air
What does the non-return valve prevent?
Keeps fuel from flowing back into the tank after the pump is switched off.
If the exhaust from a vehicle has high HC and low CO. How is the air fuel ratio can be classified?
Lean
What percentage leak is considered good?
Less than 10% leakage
If the secondary ignition signal has an exsessively long sparkline for one of the cylinders, which of the malfunctions would most likely occure?
Low resistance in one cylinder
Which of the exhaust gas is reduced by EGR system?
NOx
A cylinder compression test is being perform. Technician A says you should do a compression test on a gasoline engine with the throttle fully close. Technician B says you should crank the engine through 2 strokes to obtain the most accurate reading.
Neither
The engine in the composite vehicle will not start. A preliminary diagnosis indicates that there is no spark. Technician A says that a defective CMP sensor could be the root cause of the problem. Technician B says that the ignition module should be replaced. Who is right?
Neither Technician A nor B
All of the following statements are true EXCEPT: On a hot day, gasoline in the tank contracts. Emission of fuel vapors from the fuel tank can be controlled by sealing the fuel system from the atmosphere. Air must be allowed to enter the fuel tank to take the place of fuel as it is consumed. The fuel tank can be vented by the gas cap or by a vent solenoid.
On a hot day, gasoline in the tank contracts.
In a four cylinder engine, how often is a spark generated for cylinder 1 with a DIS ignition system?
Once per revolution.
The system that is MOST-Likely used to prevent the emission of hydrocarbons in blow-by gases from the crankcase by scavenging them from the crankcase and reintroducing them into the combustion chambers is:
PCV system
How is HC measured
PPM
How is NOx measured
PPM
A DTC P0171 (Bank 1 Fuel System too Lean) is stored. It is the only code stored. Of the following, what is the MOST likely cause for this code? Plugged injectors High fuel pressure Leaking injectors A short to ground in the MAP sensor signal wire to the PCM
Plugged injectors
If you hear air coming from a cylinder that is next to the one under being leak tested, what is the most likely cause?
Possible blown head gasket or cracked head
What is a magnetically controlled switch?
Relay
Ohms are a measure of
Resistance
When perform a cylinder compression test. Technician A said to make sure the battery is fully charged. Technician B said a compression test will always identify a specific cause of failure.
Technician A
Technician A says that ignition systems have primary and secondary circuits. Technician B says that the spark plug is part of the primary circuit. Who is right?
Technician A ONLY
Technician A says the spark must ignite all of the air fuel mixture before the piston has reached 23 degrees ATDC. Technician B says that the amount of time it takes for the fuel to burn varies with engine speed. Who is correct?
Technician A ONLY
Technician A says that low fuel pressure on port fuel injected vehicles can be caused by a partially or completely clogged fuel filters. Technician B says that high fuel pressure can be caused by a faulty fuel pump. Who is correct?
Technician A Only
02 sensor voltage is continually lower than specified. Technician A says this could cause higher‑than‑normal injector pulse width. Technician B says this condition could cause lower‑than‑normal block‑learn numbers (long‑term fuel trim). Who is right?
Technician A only
Technician A says that modern electronic ignition systems will use contact points and condenser. Technician B says that new, as well as, older vehicles advance and retard the ignition spark timing. Who is right?
Technician B ONLY
Technician A says to test a vacuum controlled fuel pressure regulator you can start the vehicle and measure the fuel pressure, then remove the vacuum hose from the fuel regulator and verify the fuel pressure decreases. Technician B says that a faulty fuel pressure regulator can cause the fuel pressure to go both below and above specification. Who is correct?
Technician B Only
Engine coolant Temperature (ECT): 210 Deg F 0.50 V Intake Air Temperature (IAT): 96 deg F 2.4 V Mass Airflow Sensor (MAF): 50 gm/sec 3.00 V Throttle Actuator Control Motor (TAC): 35 % Throttle Position Sensor 1 (TP1): 0% 0.00 V Throttle Position Sensor 2 (TP2): 35% 2.00 V Accelerator Pedal Position Sensor 1 (APP1): 100% 3.5V Accelerator Pedal Position Sensor 2 (APP2): 100% 4.50V Crankshaft Position Sensor (CPS): 1900 RPM Heated Oxygen Sensor Bank1 (HO2S1/1): 0.01-0.90 V Heated Oxygen Sensor Bank2 (HO2S2/1): 0.01-0.90 V Heated Oxygen Sensor Post-CAT (HO2S1/2): 0.4 V Vehicle Speed Sensor (VSS): 55 mph EVAP Canister Purge Solenoid: 30 % EVAP Canister Vent Solenoid: Off Fuel Pump Relay (FP): On The composite vehicle is sluggish on acceleration and will not exceed 55 MPH and the MIL is on. A check of basic systems shows all components to be in good condition. The scan tool data in the table above was obtained on a test drive. The throttle pedal was wide open going 55 MPH. What is limiting the vehicle speed?
The Throttle Position Sensor 1 is inaccurate.
Which component the dIstributorless ignition system determines the precise moment the ignition coil fires?
The control unit
The COP / pen coil generates a high voltage.Which component determines the precise moment when this happens?
The engine control unit (ECU).
Which of the following conditions should be completed for a proper cylinder compression test?
The engine should be at normal operating temperature. Remove all the spark plugs Be sure the ignition is system is disabled so the vehicle will not run. Make sure the throttle is fully open
Which of the following conditions should be completed for a proper cylinder leakage test?
The engine should be at normal operating temperature. Remove all the spark plugs. Be sure the piston is at TDC on the compression stroke.
Which of the following fuel system statements are true.
The fuel system is in closed loop when the engine computer used the oxygen sensor information to control the fuel. The engine should be at a normal operating temperature before the fuel system enters closed loop. There must not be any engine DTCs before the fuel system enters closed loop. The check engine light (MIL) should be off.
What is an injector?
The injector is an actuator.
What is true about the injectors used for port fuel injection?
The injector sprays gasoline in the direction of the intake valve. The injector nozzle has more than one spray opening.
What is true about a conductor?
The longer a conductor is, the more resistance it has The larger its diameter, the less resistance it has
Define the term induction.
The physical principle in which a voltage is generated in a conductor, when it is subjected to a change in the magnetic field.
Which part forces the injector needle into the seat?
The return spring
Which of the following statements is LEAST-Likely true? A liquid vapor separator is part of the fuel tank or the expansion tank. The rollover valve has a ball or plunger that blocks the fuel line when the vehicle is started. A vapor canister is only allowed to purge itself of vapor storage when the engine is running. Some cars have a rollover valve in the vent line from the fuel tank.
The rollover valve has a ball or plunger that blocks the fuel line when the vehicle is started.
When the MIL is on, what does this mean? The vehicle has to be experiencing a driveability problem The vehicle will not start There is a DTC stored in memory There must be an electrical failure in a sensor or circuit
There is a DTC stored in memory
Which of the following is a type of fuel system?
Throttle Body Injection System Carbureted Fuel System Sequential Port Dual Fuel System
If a 12V parallel circuit contains two twelve-ohm loads, which of the following is true?
Total Resistance is 6 ohms Total Current is 2 Amps
A load is any device that turns electrical energy into another form of energy, such as light, sound, heat, or mechanical energy.
True
If the cylinder pressure is lower than manufacturer's specification what is the most likely cause?
Unable to determine with this test
Which of the following statements is true?
Without insulation surrounding the conductor, electricity would take undesired paths. Resistance is an obstruction to electrical flow.
If the cylinder pressure is lower than manufacturer's specification and you squirt about 1 tablespoon of oil in the cylinder and the pressure improves more than 25 psi, what is the most likely cause?
Worn or defective piston rings.
If the first puff of a cylinder compression test is les than 50% of the final pressure what is most likely the failure?
Worn or defective piston rings.
If a wet cylinder compression test increases the compression by more than 25 psi. What is the most likely cause?
a bad ring
All of the following statements about the air injection system are true EXCEPT:
a high-pressure vane-type pump driven by a crankshaft belt provides air.
Which one of the following monitors can cause the MIL to flash?
a misfire
Select the following statements that are true.
a. Voltage differential controls how strongly a load in a circuit is operated. b. When voltage differential is lower than normal, a light will not be as bright or a heater defroster motor will not spin as fast. d. Voltage differential is the difference between battery voltage at one end of a circuit and zero voltage on the ground side.
When will the DIS igniton coils be switched on?
alternately, one at a time.
In a DIS igniton system on a four cylinder vehicle, with respect to the spark plugs of cylinder 1 and 4, the spark plugs of cylinders 2 and 3 spark:
half a revolution later (180°).
The part that is MOST-Likely mounted closer to the engine than the muffler so it can be quickly heated by exhaust is:
catalytic converter
Select the correction statements with regard to using voltmeter.
connected in parallel used to measure volt used on "live" circuits set for the proper scale before connecting to circuit
Select the correction statements with regard to using an ammeter.
connected in series
For a ground or return circuit, the automobile uses the:
engine and car frame
Aluminum is an oxide of alumina that is very porous.
false
Positive crankcase ventilation systems today are open PCV systems.
false
A cylinder leak test is diagnostic procedure that can used to detect
faulty piston rings, cylinder head gasket, valves, cracked block
Technician A says when performing a leak test on a fuel injected vehicle that has a catalytic converter you must remove one spark plug wire at a time and measure the RPM drop for each cylinder. Technician B says before performing a cylinder leak test, the engine should be cold. Who is correct?
neither
13 to 1 air fuel ratio. how is it be classified?
not enough air --> rich
Three-way catalytic converters use _________, or sometimes palladium, as a catalyst for their reduction portion (the part that controls NOX).
rhodium
firing line lower than normal
too little resistance
Firing line higher than normal
too much resistance
spark line is shorter than normal
too much resistance
CO2 is a greenhouse gas that traps heat in the atmosphere.
true
Carbon monoxide (CO) emissions result when gasoline is not completely burned.
true
Exhaust backpressure is a good indicator of engine load.
true
Protons and neutrons are located in the nucleus (center) of the atom, while the electrons move about in orbits around the nucleus.
true
Select the following statements that are true.
variable resistors, called rheostats or potentiometers, are also used to control the speed and intensity of electrical loads a rheostat varies current flow through the circuit a potentiometer varies the voltage in a circuit