Practice Test Geeks(CTE) Certified Teacher Career and Technical Education Practice Test
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Engine Performance & Tuning Flashcards

7 cards from real CTE practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.

Read the first 7 Engine Performance & Tuning flashcards as text

  1. What is the purpose of an exhaust gas recirculation (EGR) system in engine performance?

    Answer: Reduce NOx emissions by lowering peak combustion temperatures

    Recirculating inert exhaust gases dilutes the intake charge, lowering combustion temperature and reducing NOx formation.

  2. During a cylinder leakage test, air escaping from the throttle body indicates:

    Answer: A leaking intake valve

    Air traveling back through the intake path (toward the throttle body) points to an intake valve that is not sealing properly.

  3. Which data PID should a CTE instructor recommend students monitor to detect a clogged catalytic converter?

    Answer: Upstream vs. downstream O2 sensor switching rates

    A functioning catalyst causes the downstream O2 sensor to switch much more slowly than the upstream; similar switching rates indicate catalyst failure.

  4. Detonation (engine knock) under load is most likely caused by which combination of factors?

    Answer: High compression ratio, low-octane fuel, or excessive ignition advance

    High cylinder pressure combined with low-octane fuel or too-advanced timing causes the end-gas to auto-ignite before the flame front arrives.

  5. What does a flat-line (non-switching) upstream O2 sensor waveform most likely indicate?

    Answer: A faulty or poisoned O2 sensor stuck in a fixed voltage

    A healthy upstream O2 sensor should oscillate between rich and lean; a flat signal indicates it is not responding and needs replacement.

  6. In a direct injection (GDI) engine, where is the fuel injected?

    Answer: Directly into the combustion chamber under high pressure

    GDI systems inject fuel directly into the cylinder at very high pressure, enabling better atomization and higher compression ratios.

  7. A CTE student asks why turbocharger lag occurs. The correct explanation is:

    Answer: The turbine takes time to spin up to speed on exhaust gas energy before boost builds

    Turbo lag is the delay between throttle application and boost buildup while exhaust energy accelerates the turbine wheel to operating speed.