41 (KELLY)

T or F: throttle values are not used on diesel engines

T

the titania sensor is_____ than a zirconia oxygen sensor

smaller

the ECM compares the voltage produced by the zirconia oxygen sensor to a reference voltage of approximately____mV - 250 - 400 - 450 - 500

450

when the free oxygen or free fuel has been neutralized, the voltage feedback signal drops to about____mV (same as Vref) and no pump current is supplied to the pump cell - 300 - 400 - 450 - 500

450

a___ was the first electronic fuel injection fuel injection system used on passenger cars

TBI (throttle body injection)

a____ engine monitors the operating temp of the engine

engine coolant temp sensor

manifold pressure is an excellent indicator of____.

engine load

define vacuum

a pressure lower than atmospheric pressure that is formed in a enclosed area

define engine throttle actuator

a small reversible servo motor w/ an emergency release

define multiport injection system

has fuel injectors in the intake ports. gas is sprayed into each intake port, toward each intake valve

explain the purpose of an intake air temp. sensor

helps the computer compensate for changes in out-side air temp. and maintain an almost perfect air-fuel mix ratio

the surface of the zirconia oxygen sensor is coated in ____, which helps the sensor maintain a high operating temp.

platinum

to increase fuel pressure, the ECM send a longer duty cycle and more___ to the electromagnet to force a small relief valve closed

current

a____ injection system forces fuel into the engine combustion chambers

direct

a piezo fuel injector uses a crystalline ceramic material instead of a ____ to open the injector valve

electromagnetic

older fuel injection systems use either ____ fuel injection or _____ fuel injection

- continues fuel injection - intermittent fuel injection

name 4 components of a solenoid fuel injector

- electronic terminals - injector solenoid - inlet screen - needle valve

name the 5 subsystems of all electronic fuel injection systems

- fuel delivery system - air induction system - sensor system - computer control system - fuel metering system

a rich mix will produce (low,high)____ voltage and a lean mixture will produce (low,high)____voltage

- high - low

a timed injection system sprays fuel into the engine during the ____ or ____ strokes, in relation to piston and valve action

- intake - compression

how are new direct fuel injection system different from old DFI systems

- old systems were all- mechanical diesel injection - new systems are both mechanical and electronic

name 5 sensors used to help control the operation of a gasoline injection system

- oxygen sensor - manifold absolute pressure sensors - throttle position sensors - accelerator pedal sensors - airflow sensors

current flow through the piezo crystal in one direction causes the atoms in the crystal to (attract,repel)____ each other, physically(expanding,contracting)___ the crystal

- repel - expanding

what are the two common types of electronic fuel injectors

- solenoid - piezo

at sea level, the atmosphere experts___ psi of pressure on everything

14.7 psi

low-pressure EFI systems operate on less than____psi. a high-pressure fuel injection system w/ an engine-driven fuel pump can produce over___psi - 10, 1000 - 15, 2000 - 20, 1000 - 25, 250

15, 2000

a lean burn oxygen sensor measures the oxygen content in the exhaust of lean-burn engine at ratios as lean as____:1 -10 - 15 - 17 - 23

23:1

TorF: since a DEFI fuel pressure regulator is normally open, any loss of electric power to or from the ECM or injector amplifier will close the pressure relief valve to reduce fuel pressure

F - (open the fuel)

TorF: the needle valve, armature and return spring in solenoid-operated injectors are smaller and lighter than those used in piezo fuel injectors

F - reverse/swap injectors

a wide band oxygen sensor uses internal voltage signals to produce a small____that represents oxygen content

O2 sensor pump current

define throttle position sensor

a variable resistor connected to the throttle plate shaft

what feeds an electric signal to the ECM that corresponds to pedal position

accelerator pedal sensor

the ECM send an amplified control current to a servo motor___ that opens and closes the engine throttle valve

actuator

an idle air control is a solenoid- or servo motor-operated____valve

air bypass

a____sensor us used in many EFI systems to measure the amount of outside air entering the engine

airflow

a DEFI____ is needed to increase the voltage and current signal sent from the ECM to operate the high-pressure direct injectors

amplifier

what does a DEFI fuel pressure regulator use to bypass excess fuel pressure back to the low pressure side of the system

an electric solenoid

how are the numbers for oxygen sensor positions in vehicle assigned

by its location and order in relation to the engines banks

a____is used to direct engine speed

camshaft position sensor

define wire band oxygen sensor

can change its output gradually and in direct proportion to the oxygen content of the exhaust gasses

(open,closed) loop____means that the computer is using information from the oxygen sensor and the other sensors

closed

is the planar zirconia oxygen sensor more or less resistant to contamination and vibration than a conventional zirconia sensor

more resistant

an EFI fuel pressure regulator uses___, not the ECM, to control lower fuel pressure in multiport fuel injection systems

engine vacuum

uses a slightly richer air-fuel mix

full power charge mode

off-road race cars are often retrofitted with one or two wide band oxygen sensors to better tune and race engines for high____

horsepower

when the accelerator is released and the throttle valve is closed, the engine returns to____.

idle speed

if the engine temp sensor signals the ECM that the engine is very cold, injector pulse width will be (decreased,increased)____ to spray more fuel to help start the cold engine

increased

a___ injection system sprays fuel into the engine intake manifold

indirect

what is the function of the engine throttle valve

is a "butterfly" or flap type valve in the throttle body assembly that controls airflow and engine power output

if the engines air-fuel mix is too (lean,rich)____, there will be a smaller difference in oxygen content between the sensors surfaces

lean

if the engine is accelerated for passing speeds, the ECM will (lenghen,shrink)____ the injector pulse width to richen the air-fuel mixture for more power

lenghen

what is the function of the manifold absolute pressure (MAP) sensor

measures pressure or vacuum inside the engines intake manifold

zirconia, titania, and planar sensors are considered____band sensors

narrow

why do vehicles w/ OBD2 use two oxygen sensors for each catalytic converter

one O2 sensor before the catalytic converter and one after the catalytic converter

when in (open,closed)____loop, the electronic fuel injection system does not use engine exhaust gas content as a main indicator of the air-fuel mix

open

when the engine throttle valve is ____, atmospheric pressure pushes more air into the intake manifold

open

what is the function of an EFI oxygen sensor

or exhaust gas or O2 sensor, measures the oxygen content in the engine exhaust gasses as a means of checking combustion efficiency

define fuel rail

or fuel log, is a large diameter steel tube that feeds gas to the inlet fittings of the fuel injectors

a gasoline system uses___ from an electric or mechanical fuel pump to spray fuel into the engines intake manifold or its combustion chambers

pressure

the (primary,seconday)_____ oxygen sensor is used to monitor the oxygen in the exhaust gases as it leaves the engine

primary

a fuel pressure sensor is often used in____fuel injection systems

returnless

a solenoid fuel injector used in a multiport system is usually press-fit into the ____ in the intake manifold

runner

the (primary,secondary)____ oxygen sensor is mounted downstream in the exhaust system

secondary

what is used in many throttle body assemblies to return the engine to idle even if the engine throttle actuator fails

throttle safety release

what systems move the engine throttle values electronically instead of using conventional mechanical linkage from accelerator pedal

throttle-by-wire system or drive-by-wire systems

produces lowest emissions of all DEFI systems

stoichiometric mode

ultra-lean burn mode

stratified charge mode

explain an advantage of a titania oxygen sensor

uses a thick film of titania to determine the amount of oxygen present in the exhaust gasses

what is the function of an EFI systems fuel pressure regulator

uses engine vacuum, not the ECM, to the control fuel pressure in multiport fuel injection systems

the injector pulse___ indicates the amount of time each injector is energized and kept open

width

a____ connects the sensors to the input of the ECM and connects the output of the ECM to the fuel injectors

wiring harness