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The A8 exam has 60 questions and runs 1 hours 15 minutes.
These 10 free A8 questions are organized by exam domain, so you can see how each part of the Automobile & Light Truck Certification - A8 Engine Performance blueprint is tested. Reveal the answer and explanation under each question.
A cranking compression test produces these readings: cylinder 1, 152 psi; cylinder 2, 148 psi; cylinder 3, 88 psi; cylinder 4, 150 psi. A small amount of oil is added to cylinder 3 and the test is repeated, but the reading does not change. This MOST likely indicates:
Correct answer: A - A burned exhaust valve in cylinder 3
During a cylinder leakage test, air is heard escaping from the engine oil filler opening. Technician A says worn piston rings could be the cause. Technician B says a leaking intake valve could be the cause. Who is right?
Correct answer: A - Technician A only
A vacuum gauge connected to the intake manifold reads a steady 19 in. Hg at idle. When the engine is held at 2,500 rpm, the reading rises briefly and then falls steadily to about 8 in. Hg. This MOST likely indicates:
Correct answer: B - A restricted exhaust system
An engine cranks slowly. The battery is fully charged and tests good. Starter current draw is measured and found to be lower than specification. Which of these is the MOST likely cause?
Correct answer: C - High resistance in the starter circuit
A vehicle with variable valve timing has a rough idle and a stored DTC indicating camshaft timing over-retarded. Which of these should be checked FIRST?
Correct answer: D - Engine oil level and condition
An engine cranks but does not start. There is no spark at any cylinder and no injector pulse at any injector. Which of these is the MOST likely cause?
Correct answer: A - A failed crankshaft position sensor
A secondary ignition oscilloscope pattern shows an abnormally high firing line on one cylinder. Technician A says a fouled spark plug could be the cause. Technician B says an excessively wide spark plug gap could be the cause. Who is right?
Correct answer: B - Technician B only
A vehicle has a power loss complaint and poor fuel economy. Scan data shows the PCM is continuously retarding ignition timing, but no spark knock is audible and no unusual engine noise is present. Which of these is the MOST likely cause?
Correct answer: C - A loose or improperly torqued knock sensor
Scan data from a warmed engine operating in closed loop shows long term fuel trim at +24% at idle, dropping to +3% at 2,500 rpm. This MOST likely indicates:
Correct answer: B - An intake manifold vacuum leak
A vehicle has a P0171 system too lean (bank 1) DTC. Technician A says an exhaust leak ahead of the upstream oxygen sensor can cause this code. Technician B says a vacuum leak downstream of the mass airflow sensor can cause this code. Who is right?
Correct answer: C - Both Technician A and Technician B
The A8 exam also covers these domains. Drill them in the full free practice test:
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