Volume 3, Unit 2

how many revolutions per minute can a turbo charger operate at?

100,000

glow plugs can reach temperatures above _______

1000 degrees Fahrenheit

how much psi of pressure does the atmosphere exert at sea level?

14.7

how long does normal combustion take?

3/1000 of a second

what is typical compression pressure, in pounds per square inch, for an automotive diesel engine?

400-500

what is the operating direct current voltage of a direct electronic fuel injection injector?

50-100 volts

what is the difference in operation between a multiport injection system and a direct fuel injection system?

a multiport injection system has fuel injectors in intake ports while a direct fuel injection system injects fuel directly into the combustion chambers

what are extra chemicals added to gasoline to improve the operating characteristics?

additives

what is injector pulse width?

amount of time each injector is energized and kept open

what should you coat the threads of a diesel injector with when installing?

anti-seize compound

what is normal aspiration?

atmospheric pressure pushes air into the engine

a bad fuel injector can cause all of the following problems except: backfire, engine missing, hard starting, or poor fuel economy?

backfire

what should not be done when removing a diesel injector?

bending injection line out of the way

rich fuel mixture results in which color of diesel exhaust smoke?

black

which color of diesel exhaust smoke is due to oil consumption from worn piston rings, scored cylinder walls, or leaking valve stem seals?

blue

which type of fuel filter is found on modern diesel engines?

bowl

what should be used to locate a fuel leak in a diesel injection system?

cardboard

define stoichiometric fuel rating

chemically correct air fuel mixture

what does diesel fuel cetane rating indicate?

cold starting ability of diesel fuel

what must each high-pressure cylinder be checked for?

dents, punctures, or any other problems that may cause safety concerns

what should be used to check turbocharger clearances, shaft endplay, and runout?

dial indicator

what is often recommended for testing an EFI temperature sensor?

digital ohmmeter

what is a diesel cylinder balance test?

disabling one injector at a time to check the firing of the cylinder

what action is taken to disable the injection pump when performing a diesel compression test?

disconnect the shutoff solenoid

if an injector is operating, what sound should you hear when you touch the probe of a stethoscope on the top of the fuel injector body?

distinct clicking sound

what powers a diesel injection pump?

engine

what does an electronic fuel injection fuel pressure regulator in a multiport fuel injection system use to control fuel pressure?

engine vacuum

flex fuel vehicles are designed to operate on a mixture containing up to 85% what?

ethanol

what spins the turbine wheel of a turbocharger?

exhaust gases entering the turbine housing

what should a properly functioning oxygen sensor's output voltage be?

fluctuating between .2 and .8 volts

what is natural gas?

fossil fuel extracted from underground reservoirs

which system helps cool the fuel and prevents a vapor lock?

fuel return

what is the waste gate's position under partial load?

fully closed

what is crude oil a mixture of?

hydrocarbons

what can you learn from performing a glow plug resistance-balance test?

if each cylinder is firing

why do many service manuals warn against doing a wet compression test on a diesel?

if too much oil is squirted into a cylinder, hydraulic lock and damage could result because oil will not compress

what does diesel fuel with a higher octane number do?

ignites easily from heat and pressure

what is the purpose of a supercharger bypass valve?

improve engine efficiency by providing maximum boost only when needed

how are the supercharger rotor gears lubricated?

in a bath of oil

what is the difference in electronic fuel injection system operation when in open loop versus closed loop

in open loop, the system does not use engine exhaust gas content as a main indicator of the air fuel mixture. in closed loop, a computer uses information from sensors

what are the functions of a turbocharger intercooler?

increase engine power, cool the air entering the engine, and reduce tendency for engine detonation

what is the basic purpose of turbocharging or supercharging?

increase pressure of intake air

glow plug electrical resistance ______ with temperature

increases

what is the time span between injection of the diesel fuel and the injection of the fuel?

injection lag

what are the four major components of a diesel injection system?

injection pump, injection lines, injector nozzle, and glow plugs

what are the five major parts of a diesel injector?

injector heat shield, injector body, injector needle valve, injector spring, and injector pressure chamber

what are the most common reasons for excess white smoke from a diesel engine?

inoperative glow plugs, low engine compression, thermostat stuck open, bad injector spray pattern, late injection timing, coolant leaking into cylinders, and cold start

why does the timing on a natural gas operated vehicle require adjustment

it has a higher octane rating or slower flame speed

what can an injection-pressure tester locate?

leaking injector nozzle, clogged injector filter, and a bad injector pump

what is the function of a waste gate?

limits the amount of boost pressure developed by a turbo

what is the MAIN sensor controlling the turbocharger boost pressure

manifold absoluter pressure sensor

what device stops the flow of natural gas to the engine when there is an emergency?

manual shutoff valve

what is gasohol?

mixture of gasoline and alcohol that is used as fuel

when servicing press-fit fuel line fittings, what may need to be replaced to prevent leakage?

o-ring

what is the measurement of fuel's ability to resist knock or ping?

octane rating

which of the following is NOT a function of a diesel injection pump: produce high fuel pressure, open injector nozzles before injection, circulate fuel through lines and nozzles, or control engine idle and maximum speeds?

open injector nozzles before injection

what is a diesel fuel substance that can separate from other fuel parts and clog fuel filters?

paraffin

what is another name for crude oil?

petroleum

what type of fuel injector uses a crystalline ceramic material to open the injector valve?

piezo

what pressurizes fuel in an inline diesel injection pump?

plungers

if a vehicle's fuel pump is disabled by the inertia switch after an accident, what must be done for the pump to function again?

press the button on the inertia switch

what does the natural gas regulator do?

reduce fuel cylinder pressure and aids with achieving appropriate air and fuel mixture for combustion

before disconnecting any electronic fuel injection fuel line what should you do?

relieve fuel pressure

when the MAP sensor indicates a high load, a ______ air fuel mixture is required

rich

a black oxygen sensor tip indicates what?

rich mixture and a carbon contamination

a bad mass air flow sensor can make an engine do what?

run a little rich or lean and/or enter limp-in mode

why should you use a scan tool to check fuel pressure on modern a Direct Injection System?

safety

fuel rail pressure in a direct gasoline injection system is controlled by?

solenoid

what are the three modes of direct electronic injection systems?

stratified charge mode, stoichiometric mode, and full power mode

what should you use to loosen the turbo shaft nuts?

t-handle and socket

why does a diesel engine need a vacuum pump?

there is little vacuum in the intake manifold due to no throttle valve restriction

what is the advantage of DEFI systems over other designs?

they control air fuel mixture more precisely, lowering emissions, and fuel consumption while increasing engine power output

which type of gasoline injection system sprays fuel into the engine in relation to piston and valve action?

timed

which type of oxygen sensor varies its internal resistance rather than generating voltage to signal the engine control module?

titania

a fuel tank is UNlikely to be made of: plastic, titanium, sheet steel, or aluminum?

titanium

what is a short delay before the turbo develops sufficient boost?

turbo lag

where is the EFI system control module normally mounted?

under the dash

how do modern turbo systems reduce turbo lag?

variable vane supercharger, sequential turbos, and twin turbos

what could cause diesel fuel to turn cloudy or milky?

very cold temperatures, causing the separation of wax from the fuel

what is the purpose of the water detector?

warns the driver of water in diesel fuel

what is meant by bi-fuel?

when a vehicle can be operated on gasoline(any liquid fuel) or natural gas

what do fuel trim values indicate?

whether the ECM has had lean or richen air-fuel mixture to maintain a perfect stoichiometric mixture