ENGINE PERFORMANCE

For every task in Engine Performance, the following safety requirement must be strictly enforced:

Comply with personal and environmental safety practices associated with clothing; eye protection; hand tools; power equipment; proper ventilation; and the handling, storage and disposal of chemicals in accordance with local, state, and federal safety and environmental regulations.

Note: The CNG/LPG Engine Performance area is basically a sub-set of the Automobile Engine Performance area. Not all of the Automobile tasks are required in the CNG or LPG task list. Task areas that do not apply to the CNG/LPG program are indicated with an "N/A" in the priority column. Tasks that have been modified significantly in content or priority rating have been marked with "*" under the priority rating.

II. ENGINE PERFORMANCE  
A. General Engine Diagnosis  
1. Interpret and verify complaint; determine needed repairs. P-2
2. Inspect engine assembly for fuel, oil, coolant, and other leaks; determine needed repairs. P-2
3. Diagnose the cause of unusual engine noise or vibration problems; determine needed repairs. P-2
4. Diagnose the cause of unusual exhaust color, odor, and sound; determine needed action. P-2
5. Perform engine absolute (vacuum/boost) manifold pressure tests; determine needed repairs. P-2
6. Perform cylinder power balance test; determine needed action. P-2
7. Perform cylinder compression test; determine needed action. P-2
8. Perform cylinder leakage test; determine needed action. P-2
9. Diagnose engine mechanical, electrical, electronic, fuel, and ignition problems with an oscilloscope and engine diagnostic equipment; determine needed action. P-2
10. Prepare 4 or 5 gas analyzer, inspect and prepare vehicle for test and obtain exhaust readings; interpret readings and determine needed action. P-1
   
II. ENGINE PERFORMANCE  
B. Computerized Engine Controls Diagnosis and Repair  
1. Diagnose the causes of emissions problems resulting from failure of computerized engine controls. P-2
2. Perform analytic/diagnostic procedures on vehicles with on-board diagnostic computer systems; determine needed action. P-2
3. Inspect and test sensors, controls, and actuator components and circuits of computerized engine control systems; adjust or replace as needed. P-2
4. Obtain and interpret digital multimeter (DMM) readings. P-1
5. Read and interpret technical information. P-1
6. Locate and interpret vehicle and major component identification numbers (VIN, vehicle certification labels and calibration decals). P-2 1
7. Inspect and test power and ground circuits and connections; service or replace as needed. P-2
8. Practice recommended precautions when handling static sensitive devices. P-2
9. Inspect, test, service, disassemble and assemble wire harness connectors and wire taps, using manufacturer's specifications. P-2
   
II. ENGINE PERFORMANCE  
C. Ignition System Diagnosis and Repair  
1. Diagnose no-starting, hard starting, engine misfire, poor driveability, spark knock, power loss, poor mileage, and emissions problems on vehicles with electronic ignition systems; determine needed repairs. P-2
2. Inspect and test ignition primary circuit wiring and components; repair or replace as needed. P-2
3. Inspect and test distributor; service as needed. P-2
4. Inspect and test ignition system secondary circuit wiring and components; replace as needed. P-2
5. Inspect and test ignition coil(s); replace as needed. P-2
6. Check and adjust (where applicable) ignition system timing and timing advance/retard. P-2
7. Inspect and test ignition wiring harness and connectors; replace as needed. P-2
8. Inspect and test ignition system pick-up sensor or triggering devices; replace as needed. P-2
9. Inspect and test ignition control module; replace as needed. P-2
   
II. ENGINE PERFORMANCE  
D. Fuel, Air Induction, and Exhaust Systems Diagnosis and Repair  
1. Diagnose hot or cold no-starting, hard starting, poor driveability, incorrect idle speed, poor idle, flooding, hesitation, surging, engine misfire, power loss, stalling, poor mileage, dieseling, and emissions problems on vehicles with carburetor-type fuel systems; determine needed action. P-3 *
2. Diagnose hot or cold no-starting, hard starting, poor driveability, incorrect idle speed, poor idle, flooding, hesitation, surging, engine misfire, power loss, stalling, poor mileage, dieseling, and emissions problems on vehicles with injection-type fuel systems; determine needed action. P-3 *
3. Inspect and replace fuel tank, fuel cap, fuel lines, fittings, and hoses. P-2
4. Check fuel for contaminants and quality. P-3
5. Inspect and test mechanical and electrical fuel pumps and pump control systems; replace as needed. P-2
6. Replace fuel filters. P-2
7. Inspect and test fuel pressure regulation system and components of injection type fuel systems; adjust or replace as needed. P-2
8. Inspect and test cold enrichment system components; adjust or replace as needed. P-2
9. Remove, clean, and reinstall throttle body; adjust related linkages. P-2
10. Inspect and test fuel injectors; clean or replace as needed. P-2
11. Inspect throttle body mounting plates, air induction and filtration system, intake manifold, and gaskets; clean or replace as needed. P-2
12. Check/adjust idle speed and fuel mixture where applicable. P-3
13. Remove, inspect, and test vacuum and electrical components and connections of fuel system; repair or replace as needed. P-2
14. Inspect exhaust manifold, exhaust pipes, mufflers, resonators, tail pipes, and heat shields; repair or replace as needed. P-1
   
II. ENGINE PERFORMANCE  
E. Emissions Control Systems Diagnosis and Repair  
1. Positive Crankcase Ventilation
1. Diagnose the cause(s) of emissions problems resulting from failure of the positive crankcase ventilation system. P-2
2. Inspect and test positive crankcase ventilation (PCV) filter/breather cap, valve, tubes, orifices, and hoses; service or replace as needed. P-2
2. Spark Timing Controls
1. Diagnose the cause(s) of emissions problems resulting from failure of the spark timing control system. P-2
2. Inspect and test circuits of spark timing control systems; replace as needed. P-2
3. Idle and Deceleration Speed Controls
1. Diagnose the cause(s) of emissions problems resulting from failure of the idle and deceleration speed control system. P-2
2. Inspect and test wiring, hoses, and components of idle speed control systems; adjust or replace as needed. P-2
3. Inspect and test electrical components, circuits, vacuum components, and hoses of deceleration controls; adjust or replace as needed. P-2
4. Exhaust Gas Recirculation
1. Diagnose the cause(s) of emissions problems caused by failure of the exhaust gas recirculation (EGR) system. P-2
2. Inspect and test valve, valve manifold, and exhaust passages of exhaust gas recirculation (EGR) systems; service or replace as needed. P-2
3. Inspect and test vacuum/pressure controls, filters, and hoses of exhaust gas recirculation (EGR) systems; service or replace as needed. P-3
4. Inspect and test electrical/electronic sensors, controls, and wiring of exhaust gas recirculation (EGR) systems; repair or replace as needed. P-2
5. Exhaust Gas Treatment
1. Diagnose the cause(s) of emissions problems resulting from failure of the air injection or catalytic converter systems. P-2
2. Inspect and test mechanical components of air injection systems; service or replace as needed. P-2
3. Inspect and test electrical/electronically operated components and circuits of air injection systems; replace as needed. P-2
4. Inspect and test components of catalytic converter systems; replace as needed. P-2
6. Intake Air Temperature Controls
1. Diagnose the cause(s) of emissions problems resulting from failure of the intake air temperature control systems. P-2
2. Inspect and test components of inlet air temperature control systems; replace as needed. P-2
7. Early Fuel Evaporation (Intake Manifold Temperature) Controls
1. Diagnose the cause(s) of emissions problems resulting from failure of early fuel evaporation control systems. P-2
2. Inspect and test components of early fuel evaporation control systems; service or replace as needed. P-2
8. Evaporative Emissions Controls
1. Diagnose the cause(s) of emissions problems resulting from failure of evaporative emissions control system. P-2
2. Inspect and test components and hoses of evaporative emissions control systems; replace as needed. P-2
   
II. ENGINE PERFORMANCE  
F. Engine Related Service  
1. Adjust valves on engines with mechanical or hydraulic lifters. P-2
2. Verify correct camshaft timing; determine needed action.crankcase ventilation system. P-2
3. Verify engine operating temperature; determine needed action. P-2
4. Perform cooling system pressure tests; check coolant condition; inspect and test radiator, pressure cap, coolant recovery tank, and hoses; service or replace as needed. P-2
5. Inspect and test thermostat, by-pass, and housing; replace as needed. P-2
6. Inspect and test mechanical/electrical fans, fan clutch, fan shroud/ducting, and fan control devices; service or replace as needed. P-2

Next

National Automotive Technicians Education Foundation
101 Blue Seal Drive, SE, Suite 101 ยท Leesburg, VA 20175
(703) 669-6650 Fax: (703) 669-6125
webmaster@natef.org