ASE Automobile (A1–A8) Practice Test

样题与解析

以下是本题库中的部分真题与完整解析。完整题库请用上方的刷题工具。

1. 1. Engine Repair (A1)

   A cylinder head is warped beyond specification. Which service is normally required to restore a flat sealing surface?

   • a.Retorquing the head while hot
   • b.Replacing the head bolts only
   • c.Resurfacing (machining) the head
   • d.Installing a thicker head gasket

   答案: c

   解析: A warped head must be resurfaced by machining to bring the deck within flatness specification. A thicker gasket will not correct an uneven surface, and simply retorquing does not remove the warp. Excessive material removal, however, can raise compression and change valve timing on some engines.

2. 2. Suspension & Steering (A4)

   Technician A says tires should be rotated to promote even wear. Technician B says the tire's load index and speed rating should meet or exceed the vehicle's requirements. Who is correct?

   • a.Neither A nor B
   • b.Technician B only
   • c.Both A and B
   • d.Technician A only

   答案: c

   解析: Rotation evens out the different wear rates at each position, and replacement tires must meet the vehicle's load and speed ratings for safe operation. Both statements are correct service practice. Always follow the recommended rotation pattern for the drivetrain type.

3. 3. Heating & A/C (A7)

   The expansion valve or orifice tube controls:

   • a.The flow of refrigerant into the evaporator, causing a pressure drop
   • b.Compressor speed
   • c.Blower motor voltage
   • d.Cabin air recirculation

   答案: a

   解析: The metering device drops the refrigerant pressure and controls flow into the evaporator, allowing it to boil and absorb heat. A restricted orifice or stuck valve causes poor cooling and abnormal pressures. It separates the high side from the low side of the system.

4. 4. Engine Repair (A1)

   When installing a cylinder head, the head bolts should be tightened:

   • a.Only by feel with an impact gun rather than a torque wrench
   • b.From one corner straight across to the opposite corner in a single pass
   • c.To full final torque in random order to save time on the job
   • d.Gradually in the specified sequence, usually center outward

   答案: d

   解析: Tightening in the manufacturer's sequence, typically working outward from the center in stages, distributes clamp load evenly and prevents warping the head or crushing the gasket. Skipping the sequence causes leaks. Many heads use a torque-plus-angle procedure with new bolts.

5. 5. Transmission & Drivetrain (A2/A3)

   A limited-slip differential that chatters or shudders while turning slowly is often corrected by:

   • a.Increasing the tire pressure well above the placard specification
   • b.Adding the specified friction-modifier additive to the gear oil
   • c.Replacing the wheel speed sensor mounted at the affected axle
   • d.Adding a small amount of brake fluid directly into the axle housing

   答案: b

   解析: Clutch-type limited-slip units need a friction modifier so the plates release smoothly; without it, they grab and chatter in tight turns. Using the correct gear oil with additive cures it. Persistent noise may mean worn clutch plates.

6. 6. Brakes (A5)

   A banjo bolt connecting a brake hose to a caliper should be reassembled with:

   • a.No sealing washers at all as long as the bolt is tightened firmly
   • b.New copper crush washers, torqued to spec
   • c.A coat of anti-seize applied to both of the washer sealing faces
   • d.The original washers reused along with thread sealant on the bolt

   答案: b

   解析: Banjo fittings seal with soft copper crush washers that deform once, so new washers and proper torque are needed to prevent a leak. Reused washers often weep fluid. The banjo bolt has hollow passages for fluid flow.

7. 7. Suspension & Steering (A4)

   Technician A says a worn ball joint can produce a clunk and cause a failed alignment. Technician B says a worn ball joint can wear a tire and, if it separates, cause loss of control. Who is correct?

   • a.Neither A nor B
   • b.Technician B only
   • c.Both A and B
   • d.Technician A only

   答案: c

   解析: A worn ball joint clunks, shifts alignment, wears tires, and can fail dangerously if it separates. Both technicians are correct. Worn joints are replaced before performing an alignment.

8. 8. Engine Performance (A8)

   In a port fuel-injection system, the quantity of fuel delivered by each injector is controlled mainly by the:

   • a.diameter of the fuel return line that carries excess fuel back to the tank
   • b.length of time (pulse width) the PCM holds the injector open
   • c.spring pressure that is set inside the mechanical fuel pressure regulator
   • d.resistance value that is printed on the injector's electrical connector

   答案: b

   解析: With fuel pressure held relatively constant, the PCM meters fuel by varying injector on-time, called pulse width. Longer pulse width delivers more fuel for acceleration or enrichment. Fuel trims adjust pulse width to keep the mixture near stoichiometric.

9. 9. Engine Performance (A8)

   An injector balance test is used to:

   • a.check the oxygen-storage efficiency of the catalytic converter
   • b.compare fuel delivery among injectors by measuring pressure drop
   • c.measure the electrical resistance of the ignition coil primary winding
   • d.verify the internal calibration of the mass airflow sensor element

   答案: b

   解析: Pulsing each injector for the same time and comparing the fuel-rail pressure drop, or the rpm change from cylinder power balance, reveals a weak or leaking injector. A cylinder that differs sharply signals a fueling problem. This isolates a mechanical injector fault from other misfire causes.

10. 10. Electrical (A6)

    The preferred method for a reliable, permanent automotive wire repair is generally to:

    • a.solder or use a proper crimp connector, then seal the joint
    • b.twist the bare wires together and wrap them with electrical tape only
    • c.splice by pressing metal staples through the wire's insulation
    • d.join the connection together using a common household wire nut

    答案: a

    解析: A soldered or properly crimped connection sealed with adhesive-lined heat shrink resists corrosion and vibration for a durable repair. Twisting and taping or using wire nuts is unreliable in a vehicle's environment. Manufacturer procedures may specify crimp-and-seal for certain circuits.