ASE A8 study guide
ASE A8 · Work through your exam, one topic at a time.
ASE A8, Engine Performance, is one of the automobile certification tests in the ASE certification test series administered by the National Institute for Automotive Service Excellence. ASE describes its certification as verifying that automotive service professionals have proven technical knowledge in the automotive industry, and states that ASE certifies automotive service professionals across the country. The ASE A8 study guide has 6 sections and about 1,805 words.
01General Engine Diagnosis
A general engine diagnosis begins with verifying the customer complaint and duplicating the condition. Record the symptom - crank/no-start, stall, misfire, lack of power, noise, vibration, fluid loss, or abnormal exhaust - and check for DTCs and freeze-frame data before touching hardware.
305 words, about 2 min02Computerized Engine Controls Diagnosis and Repair
The PCM reads sensors (MAP, MAF, TP, ECT, IAT, CKP, CMP, O2, knock) through a 5-volt reference, signal, and ground circuit, then commands injectors, coils, and actuators. Know sensor types: potentiometers (TPS, APP) sweep voltage; thermistors (ECT, IAT) change resistance with temperature; Hall-effect and inductive sensors generate speed signals; hot-wire MAF sensors report airflow.
302 words, about 2 min03Ignition System Diagnosis and Repair
The ignition system turns battery voltage into a high-voltage spark at the correct cylinder and time. Understand the primary circuit (B+, coil primary winding, module/ignition control, ground), the secondary circuit (coil secondary, plug wire or boot, spark plug), and triggering (CKP/CMP, distributor, or coil-on-plug logic).
313 words, about 2 min04Fuel, Air Induction, and Exhaust Systems Diagnosis and Repair
Fuel systems must deliver the right pressure and volume at the right time. Check key-on/engine-off pressure, running pressure, and pressure drop-off after shutoff.
297 words, about 1 min05Emissions Control Systems Diagnosis and Repair
Emission systems control HC, CO, and NOx. The PCV system returns crankcase vapors; a stuck-open PCV leans the mixture, a plugged one pressurizes the crankcase.
310 words, about 2 min06Engine Related Service
This domain covers work that supports engine performance: timing belts and chains, valve lash, head gaskets, cooling systems, oil leaks, mounts, and scheduled maintenance. Know which engines are interference designs - if the belt or chain breaks, valves and pistons collide.
278 words, about 1 min