Engine Performance

The engine coolant temperature sensor is typically found in the radiator.

False

Which of the following sensors is NOT used by the computerized ignition system to control ignition timing?

a. oxygen sensor

Two technicians are discussing OBD-II monitor readiness status. Technician A says that the vehicle must be driven through a drive cycle that includes several minutes of idle, low-speed cruise, medium-speed cruise, and deceleration before all monitors can be performed. Technician B says all monitors can be performed in five minutes of fast idling. Who is correct?

a. A only

Ignition spark typically occurs a few degrees _______.

a. before top dead center (BTDC)

An accelerator pedal position sensor (APP) is used on vehicles equipped with ______.

a. electronic throttle control

Which of the following jobs is NOT a function of the ignition system?

a. engaging the starter motor

When the cylinders are deactivated on a displacement on demand system, _____.

a. half of the cylinders continue to fire normally

The typical amount of secondary coil voltage required to jump the spark plug gap is ____ volts.

10,000

A conventional oxygen sensor needs to be heated to ________ degrees Fahrenheit before it can produce a usable signal.

750

A vehicle towed into the shop will crank but won't start. A quick check under the hood reveals that the spark plugs are not firing and the injectors are not receiving a pulse from the PCM. The technician notices that the MIL light does not come on when the key is turned to the run position. What should he do next?

Check the PCM's fuses, power wires, and ground wires

During the EVAP monitor vacuum pull-down test, the canister vent solenoid is held open.

False

Data collected by system sensors is stored in _____ memory.

RAM

Because air/fuel ratio sensors produce a signal only after their current output has been processed by the PCM, they cannot be tested with a voltmeter or lab scope.

True

Mode 6 data show the results of the monitor diagnostic tests.

True

The PCM can be electronically linked to other control modules

True

An air/fuel ratio sensor is different from an oxygen sensor in that ______.

a. the signal output is a varying current (amps) b. as the mixture becomes leaner, its output signal increases c. the output responds to minor changes in air/fuel mixture d. All the answers are correct.

Which of the following statements is not true?

b. A type B misfire will cause the MIL light to flash

Coil-over-plug ignition systems are being discussed, Technician A says COP coils have less time between each firing cycle, which increases the heat in the coil and can cause premature failure. Technician B says the COP system allows the ignition timing for each cylinder to be individually changed for maximum performance as the system responds to knock sensor signals. Who is correct?

b. B only

Computer-controlled ignition timing is being discussed. Technician A says when excessive wheel slippage occurs, the PCM will advance the timing to increase the torque output from the engine. Technician B says to provide smooth shifting of an automatic transmission, the PCM will temporarily retard the ignition timing to reduce the engine's torque when the transmission is beginning to change gears.

b. B only

Crankshaft sensors are being discussed. Technician A says the signal from a Hall-effect CKP cannot be used to synchronize fuel injector timing with the engine. Technician B says some early distributor ignition systems relied on photoelectric sensors to monitor crankshaft position. Who is correct?

b. B only

The two types of ignition systems are EI (electronic ignition) and ______.

b. DI (distributor ignition)

Which of the following is NOT an advantage of an electronic spark control system?

b. It allows lower compression ratio engines to be as efficient as higher compression ratio engines

The injector pulse width is the ______.

b. amount of time the injector opens and sprays fuel

The device that protects the PCM and other electronic components from the voltage spike created in the windings of a solenoid, relay, or magnetic clutch when they are turned off is called a ______.

b. clamping diode

The sensor and output status data stored when a DTC is set is called ______.

b. freeze frame data

The magnetic field surrounding the pickup coil in a magnetic pulse generator moves when the ______.

b. reluctor tooth begins to move away from the pickup coil

Which of the following tools is NOT used in testing engine sensors?

b. test light

Which of the following is not a PCM output?

b. thermostats

Before performing any repairs on a vehicle with an illuminated MIL light: Technician A records all DTCs and freeze frame data. Technician B checks for service bulletins.Who is correct?

c. both A and B

EGR monitors are being discussed. Technician A says some EGR system monitors EGR flow by measuring the difference in pressure as the EGR gas flows through an orifice (restriction). Technician B says some EGR monitors measure the temperature of the EGR outlet to determine whether there is gas flowing through the EGR valve. Who is correct?

c. both A and B

Engine operating modes are being discussed. Technician A says that when the engine is in closed-loop mode, the PCM monitors sensor inputs, then adjusts the timing, air fuel ratio, and emission controls. Technician B says the system will switch into open loop when the throttle is fully opened or the oxygen sensors cool down during idle. Who is correct?

c. both A and B

In EI systems using one ignition coil for every two cylinders, Technician A says two plugs fire at the same time, with one wasting the spark on the exhaust stroke. Technician B says one plug fires in the normal direction and the other in reversed polarity. Who is correct?

c. both A and B

Oxygen sensor monitors are being discussed. Technician A says the system monitors the sensor response time as the system cycles lean-rich-lean. Technician B says that at certain times the monitor varies the fuel delivery and checks for heated oxygen sensor response. Who is correct?

c. both A and B

Resistor-type spark plugs are being discussed. Technician A says the resistor increases the plug firing voltage. Technician B says the resistor helps reduce radio frequency interference (RFI), which can interfere with, or damage, radios, computers, and other electronic accessories, such as GPS systems. Who is correct?

c. both A and B

Two technicians are discussing testing switch type sensors. Technician A uses an ohmmeter. Technician B uses a voltmeter. Who is correct?

c. both A and B

Which of the following components is part of the primary ignition circuit?

c. ignition switch

Which of the following tools should not be used to test an actuator unless the technician is directed to do so by the manufacturer's service procedures?

c. jumper wires

Which of the following chemicals is NOT a pollutant?

c. nitrogen (N2)

Reach, heat range, and air gap are all characteristics that affect the performance of which ignition system component?

c. spark plugs

Oxygen sensors may become contaminated by ______.

coolant from blown head gaskets b. use of RTV silicone sealant in the intake system c. excessive oil consumption caused by worn rings. d. All the answers are correct.

Which of the following statements is NOT true?

d. A conventional oxygen sensor receives a 5-volt reference voltage from the PCM.

A MAP sensor with a varying frequency output can be tested with a(n) ______.

d. DMM with a frequency function

A vehicle with a DTC for an engine coolant temperature out of range code is being tested.The serial data stream shows the coolant temperature to be 198 degrees Fahrenheit. When the technician tests the resistance between the ETC terminals, he finds infinite resistance. The specifications call for 20 to 40 ohms at 200 degrees Fahrenheit. After the ECT is replaced and the code is erased, the system runs normally and the code and MIL illumination do not reoccur. How is this possible?

d. When the ECT failed, the PCM substituted a nominal ECT value that allowed the engine to run in limp home mode; the substituted value was displayed by the scan tool

In a GDI system (gasoline direct injection) the injector sprays fuel into the ______.

d. cylinders (combustion chamber)

Which of the following problems would NOT cause a oxygen sensor to appear bad?

d. leaking muffler to tailpipe gasket

A technician connects a DMM with a MIN/MAX/AVG function to the output of an oxygen sensor. The engine is run at 2000 RPM for several minutes. During the test, the voltage toggles rapidly between 150 and 900 millivolts. At the end of the test, the MAX voltage was .967 V, the MIN voltage was .087 V, and the AVG voltage was .683 V. Technician A says the sensor is faulty and should be replaced. Technician B says there could be a vacuum leak that caused the sensor voltage to have a higher than normal average. Who is correct?

d. neither A nor B

Engine vacuum is being discussed. Technician A says that when the engine is operating under light loads, engine vacuum is low. Technician B says that engine vacuum is high when the engine is operated under heavy loads. Who is correct?

d. neither A nor B

Technician A says spark plugs are part of the primary ignition circuit. Technician B says the battery is part of the secondary ignition circuit. Who is correct?

d. neither A nor B

Which of the following is a component of the secondary ignition circuit?

d. spark plug

To read flash codes on an OBD I Chrysler-built vehicle, you must ______.

d. turn the ignition key on and off three times in five seconds, ending with on

A camshaft position sensor provides the PCM with data needed to control _____.

fuel injector timing b. variable valve timing c. ignition coil timing (COP ignition) d. All the answers are correct.