Engine performance A/F delivery

The most important job of the fuel system is to optimize engine performance while:

• A) keeping fuel consumption and emissions to a minimum.

• B) keeping car owners happy with acceptable vehicle performance.

• C) making sure all DMV rules are adhered to.

• D) making sure the highest miles-per-gallon are achieved.

Tech A says that an electronic control unit (ECU)/power train control module (PCM) is needed to make electronic fuel injection (EFI) function correctly. Tech B says that most early EFI systems were throttle body injection (TBI) type systems. Who is correct?

• A

• B

• Both

• none

Which of these fuel systems places the fuel injectors in the cylinder head where they can spray fuel directly into the combustion chamber?

• A) Gasoline direct injection (GDI)

• B) Throttle body injection (TBI)

• C) Multipoint fuel injection (MPFI)

• D) Electronic fuel injection (EFI)

For gasoline to burn properly, it must be mixed with the right amount of:

• A) carbon.

• B) air.

• C) hydrogen.

• D) lead.

For a gasoline engine, the optimum air to fuel ratio by mass is about:

• A) 12.1:1.

• B) 14.7:1.

• C) 16.3:1.

• D) 18.5:1.

The term “stoichiometric ratio” describes the chemically correct air–fuel ratio necessary to achieve all of these EXCEPT:

• A) complete combustion of the fuel and air.

• B) good fuel economy.

• C) maximum engine power.

• D) reasonably clean emissions.

Tech A says that most fuel-injected vehicles use one or two electrical pumps to supply the fuel system with pressurized fuel. Tech B says that with today's systems, a fuel pump is likely to be located inside the fuel tank. Who is correct?

• A

• B

• Both A and B

• Neither

Types of fuel line connections include all of these EXCEPT:

• A) banjo bolt fittings.

• B) quick couplings.

• C) flare fittings.

• D) head bolts

Tech A says that for any fuel to burn efficiently, it must be vaporized and fully mixed with the proper amount of air. Tech B says that small particles make it much easier to vaporize the fuel. Who is correct?

• A

• B

• Both

• Neither

The throttle body controls airflow with a __________ valve.

• A) solenoid

• B) two-step

• C) petcock

• D) butterfly