Chapter 24 study guide Automotive 145

Ignition spark typically occurs a few degrees _________. A. before top dead center (BTDC) B. after top dead center (ATDC) C. before bottom dead center (BBDC) D. after bottom dead center (ABDC)

A. before top dead center (BTDC)

the three pollutants found in the exhaust gases are hydrocarbons, carbon monoxide, and_____________

(NOx) oxides of nitrogen

the OBD-II system will illuminate the MIL if a failure is detected that will cause the emissions levels to exceed _____________ times the allowable standards for that model year.

1.5

The ideal or stoichiometric ratio of air to fuel (by weight) is _________________ in a gasoline engine.

14.7 to 1

All car built since _________________ are equipped with an electronic fuel injection system.

1995

all OBD-II vehicles have a minimum of ________________ oxygen sensors.

2

what is an OBD-II trip

a partial drive cycle that includes all the condition required for a particular monitor to run

a V-6 engine has an oxygen sensor in each exhaust manifold. how do you determine which one is B1 S1

determine if the sensor is installed in the bank for cylinder No.1 and if the O2 sensor is upstream

after _____________ warm-up cycles without a fault, a DTC code is erased from active memory, but the DTC and the freeze frame data will be stored as a history code with freeze frame data until it is cleared

forty

list the major components of the fuel delivery system.

fuel tank, fuel lines, fuel filters, and a pump

what is a type A misfire

if it misfires between 2% and 20% of the time, the monitor considers the misfiring to be excessive

a fault that comes and goes and is not always present is called an ______________ fault.

intermittent

what is a type B misfire

is when a cylinder is misfiring over a 1,000 revolution period.

what is the DLC and where is it found in modern vehicle

it is a data link connector and is found under the dash on driver side

what is short-term fuel trim?

makes minor adjustments to the pulse width

during the secondary AIR active test, the PCM cycles the AIR flow to the exhaust manifold on and off during closed loop operation and monitors the _____________ voltage and the short-term fuel trim value.

precatalyst HO2S

A catalytic converter monitor DTC is set after detecting faults on ______________ consecutive drive cycles.

second

what is the function of the EVAP system monitor

test the fuel tank ability to hold pressure and the purge system's ability to vent gas fumes from charcoal canister

The misfire monitor is necessary protect to the ________________ from melting during a continuous misfire.

the honey-comb material in the converter

what is the principal function of the OBD-II system

to be more comprehensive monitoring system and to allow more accurate diagnosis by technicians

a __________ or ___________ increaaes engine efficiency by forcing (pumping) more air into the cylinders.

turbo, superchargers

what is the relationship between engine load and manifold vacuum

when the engine lead increases, more air and furl is allowed which creates more power, and lowers the manifolds vacuum reading.

Higher compression ratios tend to speed up combustion. (T/F)

True

In an OBD-II system, each component is checked by a diagnostic routine to verify that it is a functioning properly. (T/F)

True

OBD-II regulations require all vehicles manufacturers to use the same names and acronyms for all electric and electronic systems related to the engine and emission control systems. (T/F)

True

Port fuel injection systems have a throttle plate assembly, but fuel never passes by the plate. (T/F)

True

Scan tools can be used to cycle on and off some actuators such as injectors, vacuum solenoids, idle air control motors, and the like. (T/F)

True

The MIL light should illuminate when the ignition switch is turned to the run position [engine not running] and go our within a few seconds after the engine is started. (T/F)

True

The PCM can be electronically linked to other control modules. (T/F)

True

The PCM can turn off the A/C compressor when the engine is operating at full throttle. (T/F)

True

Data collected by system sensors is store in ________ memory. A. RAM B. nonvolatile RAM C. ROM D. PROM

A. RAM

which of the following jobs is NOT a function of the ignition system? A.engaging the starter motor B.generating a spark with enough heat to ignite the fuel C.maintaining the spark long enough for total combustion of air and fuel D.delivering the spark at the proper time to each cylinder on the compression stroke

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 B. oil pressure to the hydraulic lifters is increased, pumping up the lifters C. the intake and exhaust valves of the deactivated cylinders are held open D. the injectors continue to fire, but no fuel flows into the combustion chamber

A. half of the cylinders continue to fire normally

Which of the following sensors is NOT used by the computerized ignition system to control ignition timing? A. oxygen sensor B. engine temperature C. manifold vacuum D. engine RPM

A. oxygen sensor

A PCM that can learn the nominal range of inputs and outputs by monitoring them over a long period of time is said the be using ____________________ strategy.

Adaptive

Which of the following statements is not true? A. A type A misfires can cause damage to the catalytic converter if the injector is not shut down B. A type B misfire will cause the MIL light to flash C. A type B misfire is set after detected faults in two consecutive drive cycles D. A type A misfire will set DTC and cause the MIL light to illuminate immediately

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

The two types of ignition systems are EI ( electronic ignition) and _________. A. MI (magneto ignition) B. DI (distributor ignition) C.MSI (miltispark ignition) D. GCI (ground circuit ignition)

B. DI (distributor ignition)

The injector pulse width is the _________. A. size of the injector nozzle B. amount of time the injector opens and sprays fuel C. voltage applied to the injector solenoid coil D. distance between the injector tip and the center of the intake port

B. amount of time the injector opens and sprays fuel

The DLC connector on a OBDII vehicle is located under the _______. A. hood, near the battery B. dash on the driver's side C. hood, on the firewall D. hood in the fuse/relay center

B. dash on the driver's side

The first decision the computer makes in determining the best operating strategy is to determine the _______. A. throttle opening B. engine operating mode C. outside air temperature D. barometric pressure

B. engine operating mode

Which of the following is NOT an advantage of an electronic spark control system? A. it compensates for changes in engine (and sometimes outside air) temperature B. it allows lower compression ratio engines to be as efficient as higher compression ratio engines C. it makes changes many times faster than older (mechanical) systems D. it has a feedback mechanism which allows it to constantly compensate for changing conditions

B. it allows lower compression ratio engines to be as efficient as higher compression ratio engines

Which of the following is not a PCM output? A. solenoids B. thermostats C. lights (indicator) D. relays

B. thermostats

Which of the following chemicals is NOT a pollutant? A. carbon monoxide (CO) B. oxides of nitrogen (NOx) C. nitrogen (N2) D. hydrocarbons (HC)

C. nitrogen (N2)

The monitor that continuously looks at all the major engine sensors and actuators that can affect emissions levels is called the _________________.

Comprehensive Component Monitor (CCM)

Besides the tailpipe, hydrocarbons (HC) can also be emitted from the _______. A.fuel tank B. hoses C. EVAP system D. All of the answers are correct

D. All of the answers are correct

In a GDI system (gasoline direct injection) the injector sprays fuel into the __________. A. intake manifold (plenum) B. intake runner in manifold C. intake port in cylinder head D. cylinders (combustion chamber)

D. cylinders (combustion chamber)

To read flash codes on an OBD I Chrysler-built vehicle, you must ________. A. connect terminals A and B on the DLC with a jumper wire B. turn the rotary switch on the PCM counter clockwise 3 clicks C. connect the E1 and TE1 terminals on the DLC D. turn the ignition key on and off three times in five seconds, ending with on

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

During the EVAP monitor vacuum pull-down test, the canister vent solenoid is held open. (T/F)

False

Higher-octane fuels are easier to ignite and burn faster than low-octane fuel. (T/F)

False

Only OBD-II equipped vehicles have sixteen-pin DLC connector. (T/F)

False

When there is a calibration update available for an OBD-II vehicle, the old EEPROM is removed from its socket in the PCM and a new EEPROM with the updates software is installed in its place. (T/F)

False

You can use a generic scan tool to access a manufacturer PID. (T/F)

False

What is the difference between closed loop and open loop engine operation?

In a open loop, the control loop is not a complete cycle and the closed loop mode does a complete cycle.

PCM stand for ____________.

Powertrain Control Module

list the steps in diagnosing a vehicle with a illuminated MIL light.

See if the MIL will either light and stay on or if it blinks. The action of the MIL depends on the monitor and the problem.

Technician A uses the snapshot function of his scan tool to record serial data during a road test that can be transferred and displayed on a PC. Technician B uses the snapshot feature of his scan tool to record the sensor data and conditions leading up to the vehicle setting a DTC. Who is correct? a. A only b. B only c. both A and B d. neither A nor B

a. A only

Catalytic converter monitors are being discussed. Technician A says that if the converter is working, the downstream signal frequency should mirror the upstream sensor. Technician B says the the downstream sensor should provide a low-frequency voltage signal. Who is correct? a. A only b. B only c. both A and B d. neither A nor B

b. B only

Diagnostic trouble codes are being discussed. Technician A says a P0442 is a manufacturer's code and means different things, depending on what manufacturer built the car. Technician B says that a P0304 code is a universal code that means the same thing no matter what manufacturer built the car. Who is correct. a. A only b. B only c. both A and B d. neither A nor B

b. B only

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? a. A only b. B only c. both A and B d. neither A nor B

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 monitores measure the temperature of the EGR outlet to determine whether there is gas flowing through the EGR valve. Who is correct? a. A only b. B only c. both A and B d. neither A nor B

c. both A and B

Engine operating modes are being discussed. Technician A says the when the engine is in closed-loop mode, the PCM monitors sensor inputs, then adjusts the timing, are 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? a. A only b. B only c. both A and B d. neither A nor B

c. both A and B

Freeze frame data is being discussed. Technician A says erasing the code with a scan tool will erase the corresponding freeze frame data. Technician B says the freeze frame data is the sensor and output status data at the instant the DTC was set. Who is correct? a. A only b. B only c. both A and B d. neither A nor B

c. both A and B

OBD II technology is being discussed. Technician A says the OBD II system has the ability to store a freeze frame (snapshot) of the operating conditions that existed when the fault occurred. Technician B says vehicle identification must be transmitted automatically to the scan tool. Who is correct? a. A only b. B only c. both A and B d. neither A nor B

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 the at certain times the monitor varies the fuel delivery and checks for heated oxygen sensor response. who is correct? a. A only b. B only c. both A and B d. neither A nor B

c. both A and B

what are flash codes

codes displayed with the MIL. it helped manufacturers identify the exact fault.

the outpur of the upstream and downstream oxygen sensors is compared to determine the efficiency of the ____________.

converter

the ____________ sensor is used by the misfire monitor to detect excessive misfires.

crankshaft position

Air/fuel ratios are being discussed. Technician A says that when the air fuel ratios is higher than 14.7 to 1 the engine produces more power. Technician B says the when the air fuel ratio is lower than 14.7 to 1 the engine uses less fuel. who is correct? a. A only b. B only c. both A and B d. neither A nor B

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? a. A only b. B only c. both A and B d. neither A nor B

d. neither A nor B

On an OBD-II vehicle, the DLC connector is located under the _______________.

dash on driver's side