ASE Advanced Engine Performance Specialist 2

Question 1

A wide-band (air/fuel ratio) oxygen sensor differs from a conventional narrow-band sensor primarily because it can:

Accepted Answer

Measure the exact air/fuel ratio across a wide range

Answer

Only switch between rich and lean at stoichiometry

Answer

Operate without a heater circuit

Answer

Read only in open loop

Question 2

A vehicle shows high long-term fuel trim (e.g., +25%) at idle but normal trim at cruise. The MOST likely cause is:

Accepted Answer

A vacuum leak

Answer

A worn timing chain

Answer

A restricted exhaust

Answer

A faulty knock sensor

Question 3

When diagnosing a P0301 (cylinder 1 misfire), the technician should FIRST:

Accepted Answer

Verify the misfire follows the cylinder by swapping coil/injector

Answer

Replace all spark plugs

Answer

Replace the ECM

Answer

Flush the cooling system

Question 4

A relative compression test using a current clamp on the starter is useful because it:

Accepted Answer

Identifies a weak cylinder without removing spark plugs

Answer

Measures coolant temperature

Answer

Tests the charging system

Answer

Calibrates the MAF

Question 5

A MAF sensor reading lower than expected grams-per-second at wide-open throttle will typically cause:

Accepted Answer

A lean condition and possible hesitation

Answer

A rich condition and black smoke

Answer

Higher idle speed

Answer

Overcharging

Question 6

Catalytic converter efficiency is best evaluated by comparing:

Accepted Answer

Upstream and downstream O2 sensor activity

Answer

Battery voltage to alternator output

Answer

Fuel pressure to vacuum

Answer

Intake and exhaust valve timing

Question 7

A P0420 code most directly indicates:

Accepted Answer

Catalyst system efficiency below threshold (bank 1)

Answer

EGR flow insufficient

Answer

EVAP large leak

Answer

Camshaft position correlation