ASE A1 ACTUAL TEST PAPER 2026
COMPLETE QUESTIONS AND CORRECT
ANSWERS GRADED A+
●● Technician A says that main bearing oil clearance can be checked
with Plastigauge. Technician B says that main bearing oil clearance can
be checked with dial bore gauge. Who is right?
Answer: Both A and B - Either method can be used to check main
bearing oil clearance.
●● Which is NOT a method of correcting excessive valve stem-to-guide
clearance?
Answer: Knurling the valve stem - The valve stem is hardened and
cannot be knurled.
●● A vacuum gauge is connected to the intake manifold of an engine
running at idle. The pointer on the gauge fluctuates rapidly but steadies
as the engine speed is increased. The test results indicate:
Answer: Worn valve guides - Worn valve guides would cause the gauge
needle to fluctuate rapidly at idle but steady as the engine speed is
increased. A leaking intake manifold gasket or late ignition timing would
cause a steady low reading. A weak valve spring would cause the gauge
need to fluctuate as engine speed increased.
, ●● A technician takes a compression reading on a 4 cylinder engine, a
gets reading of 140, 135, 135 and 40 psi. The he preforms a wet
compression test, and the readings are almost the same as those in the
first test. Technician A says that a burned valve could cause these
readings. Technician B says that a broken piston ring could cause these
readings. Who is right?
Answer: Technician A - Only technician A is correct. A burned valve will
not allow the cylinder to build compression, and the results from wet and
dry compression test will be the same. If piston rings (or worn cylinder
walls) were at fault, compression readings from a wet test would exceed
dry test results.
●● Technician A says that retarded valve timing can cause high cylinder
compression readings. Technician B says that a lean air/fuel mixture can
cause a high intake manifold vacuum reading. Who is right?
Answer: Neither A nor B - Technician A is wrong because retarded valve
timing will cause the valves to open and close at the wrong time, thereby
reducing compression and manifold vacuum readings. Retarded valve
timing can be caused by a loose timing chain or chain jumping one or
more teeth. Technician B is wrong because a low but steady manifold
vacuum reading may be caused by a lean air/fuel mixture. Air leaks or
vacuum leaks can cause a lean condition and are common causes of
rough idle, hesitation, stalling and hard starting. If the mixture is
artificially enriched by injecting propane into the induction system, an
engine running lean should speed up and the vacuum should rise.
●● An engine is being rebuilt and the crankshaft connecting rod journals
have been ground undersize. Specifications show that the original
COMPLETE QUESTIONS AND CORRECT
ANSWERS GRADED A+
●● Technician A says that main bearing oil clearance can be checked
with Plastigauge. Technician B says that main bearing oil clearance can
be checked with dial bore gauge. Who is right?
Answer: Both A and B - Either method can be used to check main
bearing oil clearance.
●● Which is NOT a method of correcting excessive valve stem-to-guide
clearance?
Answer: Knurling the valve stem - The valve stem is hardened and
cannot be knurled.
●● A vacuum gauge is connected to the intake manifold of an engine
running at idle. The pointer on the gauge fluctuates rapidly but steadies
as the engine speed is increased. The test results indicate:
Answer: Worn valve guides - Worn valve guides would cause the gauge
needle to fluctuate rapidly at idle but steady as the engine speed is
increased. A leaking intake manifold gasket or late ignition timing would
cause a steady low reading. A weak valve spring would cause the gauge
need to fluctuate as engine speed increased.
, ●● A technician takes a compression reading on a 4 cylinder engine, a
gets reading of 140, 135, 135 and 40 psi. The he preforms a wet
compression test, and the readings are almost the same as those in the
first test. Technician A says that a burned valve could cause these
readings. Technician B says that a broken piston ring could cause these
readings. Who is right?
Answer: Technician A - Only technician A is correct. A burned valve will
not allow the cylinder to build compression, and the results from wet and
dry compression test will be the same. If piston rings (or worn cylinder
walls) were at fault, compression readings from a wet test would exceed
dry test results.
●● Technician A says that retarded valve timing can cause high cylinder
compression readings. Technician B says that a lean air/fuel mixture can
cause a high intake manifold vacuum reading. Who is right?
Answer: Neither A nor B - Technician A is wrong because retarded valve
timing will cause the valves to open and close at the wrong time, thereby
reducing compression and manifold vacuum readings. Retarded valve
timing can be caused by a loose timing chain or chain jumping one or
more teeth. Technician B is wrong because a low but steady manifold
vacuum reading may be caused by a lean air/fuel mixture. Air leaks or
vacuum leaks can cause a lean condition and are common causes of
rough idle, hesitation, stalling and hard starting. If the mixture is
artificially enriched by injecting propane into the induction system, an
engine running lean should speed up and the vacuum should rise.
●● An engine is being rebuilt and the crankshaft connecting rod journals
have been ground undersize. Specifications show that the original
