Area E grew from 7 to 9 scored questions in 2026 and added air induction to its name. Its 10 tasks come in pairs: diagnose the engine problem a system causes, then inspect, test, repair or replace that system's parts. The questions stay centered on the engine: a misfire, a lean code, lost boost, a tick under the hood.
9scored questions on the test
7in the 2025 edition
10tasks, five diagnose/repair pairs
8questions on this page
What area E asks
Five systems, each as a suspect in an engine complaint (2026 task list, in our words):
Fuel: leaking injectors and seals, fuel pressure, a rich or lean mixture and what it does to the engine.
Air induction: vacuum leaks and unmetered air, filters, turbochargers, intercoolers and boost.
Electrical: the cranking and charging circuits and the wiring an engine fault can hide in.
Ignition: coils, plugs, wires and modules; swap tests that separate one from another.
Exhaust: leaks, restrictions and catalytic converters.
Diagnose first, then replace
Several wrong options here replace a part before the cause is proven:
Misfire on one cylinder: move the coil to another cylinder. If the misfire follows it, the coil is bad; if it stays, look at the plug, the injector or compression.
No spark on any cylinder with a good crankshaft sensor signal: the ignition module or its supply, the part all the coils share.
Lean code, no visible leak: smoke-test the intake before replacing sensors.
Sluggish turbo engine with low boost: a leak between the turbo and the throttle; a cracked intercooler is the answer in ASE's 2026 sample questions.
Melted catalytic converter: a result, not a cause. Fix the misfire or rich condition first, or the new converter melts too.
Tick that grows on acceleration: an exhaust manifold leak at the head.
Gas smell and fuel on the rail: a leaking injector O-ring.
High CO in exhaust gas: a rich mixture.
Oil analysis high in silicon, torn air filter: dirt in the intake, wearing the rings and cylinder bores.
Slow cranking when warm: high resistance in a battery cable, found with a voltage drop test (another official sample).
8 fuel, ignition and exhaust questions
0 of 8 answered · 0 correct
Question 1 of 8 · Fuel, Electrical, Ignition, Air Induction and Exhaust Systems Diagnosis and Service · 20%Not answered
An oil analysis report shows 150 ppm of iron and 80 ppm of silicon. A visual inspection reveals a torn air filter element. Which of the following is the MOST likely location of abnormal wear and required repair?
Explanation
Incorrect: Valve guide wear does not produce a silicon spike with an intake leak.
Incorrect: Pump wear does not explain a silicon spike, and the dirt came in through the intake, not the pump.
Correct: Silicon is dirt, and with high iron it points to dirt that got past the torn filter wearing the bores and rings, so the filter is the root fix.
Incorrect: Bearing wear shows up as copper and lead, not a silicon spike with a torn air filter.
Incorrect: Cam and lifter wear leaves iron, but the torn filter points first to wear in the bores and rings.
Question 2 of 8 · Fuel, Electrical, Ignition, Air Induction and Exhaust Systems Diagnosis and Service · 20%Not answered
A vehicle runs rough and has a P0303 code (Cylinder 3 Misfire). After swapping the spark plug with another cylinder, the misfire remains on cylinder 3. After swapping the ignition coil with another cylinder, the misfire now appears on cylinder 2. What should the technician recommend?
Explanation
Incorrect: An injector fault would keep the misfire on cylinder 3 after the coil was moved.
Correct: The misfire moved with the coil, so the coil that came from cylinder 3, now on cylinder 2, is the faulty part.
Incorrect: A mechanical fault would stay in cylinder 3, not follow the coil.
Incorrect: The misfire moved with the coil; a cylinder 3 plug wire is not part of that swap.
Question 3 of 8 · Fuel, Electrical, Ignition, Air Induction and Exhaust Systems Diagnosis and Service · 20%Not answered
A technician notices an exhaust leak at the connection between the exhaust manifold and the cylinder head. Which of these symptoms would the customer MOST likely report?
Explanation
Correct: Each exhaust pulse puffs out of the gap at the head, so the leak ticks faster as engine speed rises.
Incorrect: Hard cold starting comes from fuel or ignition problems, not an exhaust leak at the head.
Incorrect: Blue smoke means oil is burning, not exhaust escaping at the manifold.
Incorrect: A manifold leak is heard first; poor economy alone is not how it shows up.
Question 4 of 8 · Fuel, Electrical, Ignition, Air Induction and Exhaust Systems Diagnosis and Service · 20%Not answered
A vehicle has no spark at any cylinder. The technician has verified that the crankshaft position sensor is producing a signal. Which of these components should be tested NEXT?
Explanation
Incorrect: Alternator output does not explain a no-spark condition while cranking.
Incorrect: Plug gap affects one plug at a time and cannot stop spark at every cylinder.
Correct: With a good crank signal and no spark anywhere, the next part in the chain is the ignition module or driver that switches the coils.
Incorrect: The EGR valve is an emissions part and has nothing to do with spark.
Question 5 of 8 · Fuel, Electrical, Ignition, Air Induction and Exhaust Systems Diagnosis and Service · 20%Not answered
A customer complains of a gasoline smell in the vehicle and poor fuel economy. During inspection, the technician notices fuel dripping from one of the injectors when the engine is off. What is the MOST likely cause?
Explanation
Incorrect: High pressure strains the seals but does not explain fuel dripping from one injector.
Correct: Fuel dripping from the outside of an injector with the engine off means the O-ring between injector and rail has failed.
Incorrect: A failed relay stops the pump and lowers pressure, so it cannot cause a leak.
Incorrect: A clogged return line raises rail pressure, not a leak at one injector.
Question 6 of 8 · Fuel, Electrical, Ignition, Air Induction and Exhaust Systems Diagnosis and Service · 20%Not answered
What condition would high CO (carbon monoxide) levels in exhaust gas analysis indicate?
Explanation
Correct: CO is the product of burning with too little oxygen, so high CO means the mixture is rich.
Incorrect: An exhaust leak pulls in outside air, which dilutes the sample and lowers CO.
Incorrect: Valve timing problems show up mainly as high HC and poor breathing, not as rich-mixture CO.
Incorrect: Low compression causes misfire and high HC, not high CO.
Question 7 of 8 · Fuel, Electrical, Ignition, Air Induction and Exhaust Systems Diagnosis and Service · 20%Not answered
When using an oscilloscope to diagnose a fuel injector circuit, which pattern indicates a normal injector operation?
Explanation
Incorrect: A flat line at system voltage means the injector is never being switched on.
Incorrect: A gradual rise with no spike means the injector coil is not being switched cleanly.
Incorrect: Erratic voltage points to a wiring or driver fault, not a healthy injector.
Correct: When the PCM grounds the injector the trace sits near 0 V for the whole on-time, then the collapsing coil throws a sharp spike at turn-off.
Question 8 of 8 · Fuel, Electrical, Ignition, Air Induction and Exhaust Systems Diagnosis and Service · 20%Not answered
A cast-iron exhaust manifold is cracked between two runners, and two of its studs have snapped. What is the most common cause?
Explanation
Incorrect: A clogged air filter limits airflow and power but puts no stress on the manifold casting.
Incorrect: Advancing the timing lowers exhaust temperature, so it does not crack the manifold.
Incorrect: Oil pressure has no path to the exhaust manifold.
Correct: Each warm-up and cool-down expands and shrinks the manifold against the head, and that thermal stress eventually cracks the casting and breaks the studs.
Answer every question to see your score
How far the A1 goes
Here a fuel, ignition or exhaust fault is a suspect in an engine complaint, and the questions stop once you have found and fixed it. Engine controls, emissions systems and drivability diagnosis in depth are on the A8 Engine Performance pages.
How do you tell a bad ignition coil from a bad spark plug?
Swap one part at a time. Move the coil to another cylinder: if the misfire moves with it, replace the coil. If it stays, swap the plug the same way, then check the injector and compression.
What causes low boost on a turbocharged engine?
Check the pressurized side first: a cracked intercooler (the official sample's answer), a loose clamp or a split charge pipe. A wastegate stuck open, a restricted air filter or a worn turbo are other causes.
How many A1 questions cover fuel, ignition and exhaust?
9 of the 45 scored questions in 2026, up from 7 in 2025.