ASE4 General Engine Diagnosis 2

Question 1

An engine has a wet compression test reading significantly higher than the dry test. This indicates:

Accepted Answer

Worn or damaged piston rings

Answer

A blown head gasket

Answer

Leaking intake valves

Answer

A cracked cylinder head

Question 2

A vacuum gauge needle fluctuates between 14 and 19 in-Hg at idle. This suggests:

Accepted Answer

An intermittent misfire or sticking valve

Answer

Late ignition timing

Answer

A restricted exhaust

Answer

Low engine compression

Question 3

During a cylinder balance test, disabling cylinder #5 drops RPM by 50 while all others drop by 200. This indicates:

Accepted Answer

#5 is weak and contributing less power

Answer

#5 has a leaking injector

Answer

#5 is the strongest cylinder

Answer

#5 has advanced timing

Question 4

A technician hears a rhythmic tapping noise that increases with engine speed. Oil pressure is normal. The MOST likely cause is:

Accepted Answer

Excessive valve clearance

Answer

A worn main bearing

Answer

A broken piston ring

Answer

A clogged oil passage

Question 5

A customer reports an engine knock that worsens under load but disappears at idle. This MOST likely indicates:

Accepted Answer

Rod bearing knock

Answer

Valve train noise

Answer

Piston slap

Answer

Timing chain rattle

Question 6

When testing cranking vacuum, the gauge reads 0 in-Hg on all cylinders. The MOST likely cause is:

Accepted Answer

A jumped timing chain or belt

Answer

Worn piston rings on all cylinders

Answer

A faulty vacuum gauge

Answer

Excessive oil viscosity