Engine Controls - Tests W/o Codes: Other Hyundai Accent I

Spark Available

1. Verify ignition fuse is not blown.
2. Verify fusible link is not blown.
3. Verify air intake system is not restricted.
4. Ensure fuel system pressure and volume are correct.
5. Check for poor fuel quality or contaminated fuel.
6. Check for use of fuel with high alcohol content.
7. Check exhaust system for restriction.

No Spark Available

1. Ensure secondary ignition system is in good condition.
2. Ensure pick-up coil air gap is correct.
3. Ensure ignition coil supply voltage is correct.
4. Ensure ignition coil primary resistance is correct.
5. Ensure ignition coil secondary resistance is correct.
6. Ensure ignitor resistance is correct.
7. Inspect ignitor primary leads for open or short circuit.
8. Ensure ECM has correct voltage supply and is properly grounded.

DIFFICULT TO START (CRANKS OKAY)

1. Ensure sufficient secondary spark is available.
2. Inspect air intake system for restriction.
3. Ensure vacuum hoses are not disconnected or damaged.
4. Ensure fuel system pressure is correct.
5. Ensure fuel injector operation is correct.
6. Ensure EGR valve operation is correct.
7. Ensure EGR valve closes completely.
8. Inspect for cracks or poor connections at throttle body.
9. Ensure ignition and valve timing are correct.
10. Ensure distributor pick-up coil air gap is correct.
11. Ensure distributor pick-up coil resistance is within specification.
12. Ensure ignition coil resistance is within specification.
13. Test coolant temperature sensor operation.
14. Test control relay operation.
15. Check power transistor operation.
16. Test operation of air induction valve.
17. Ensure electrical harness and connectors are not broken or loose.
18. Ensure ECM has correct voltage supply and is properly grounded.
19. Ensure engine has sufficient compression.

ENGINE SURGES

1. Ensure there are no vacuum leaks.
2. Ensure EGR valve operation is correct.
3. Ensure EGR valve closes completely.
4. Ensure fuel system pressure is correct and constant.
5. Ensure ignition timing is correct.

ROUGH OR UNSTABLE IDLE

1. Inspect IAC valve for malfunction.
2. Ensure fuel system pressure is correct.
3. Ensure idle speed is correct.
4. Inspect air intake system for restrictions.
5. Use stethoscope to verify fuel injector operation.
6. Ensure sufficient spark is available at all cylinders.
7. Verify vacuum hose routing is correct and that there are no vacuum leaks.
8. Ensure fuel system pressure and volume are correct.
9. Inspect for EGR system malfunction.
10. Test coolant temperature sensor operation.
11. Test intake air temperature sensor operation.
12. Verify throttle position sensor has correct adjustment and resistance value.
13. Inspect air conditioner switch operation.
14. Inspect inhibitor switch operation (automatic transmission).
15. Test for IAC servo drive signal and operation.
16. Test airflow sensor voltage output.
17. Test barometric pressure sensor voltage output.
18. Test crankshaft position sensor operation.
19. Inspect vehicle speed sensor operation.
20. Inspect TDC sensor or cylinder No. 1 sensor operation.
21. Inspect electrical connections at fuel injectors.

EXCESSIVELY FAST IDLE

1. Check throttle cable adjustment.
2. Verify vacuum hose routing is correct.
3. Ensure there are no vacuum leaks.
4. Ensure fuel system pressure and volume are correct.
5. Test coolant temperature sensor operation.

ENGINE STALLS

1. Ensure air intake system is not restricted.
2. Ensure PCV system operation is correct.
3. Test EGR system for correct operation.
4. Inspect for cracks or poor connections at throttle body.
5. Test coolant temperature sensor operation.
6. Ensure fuel system pressure is correct. Use ohmmeter to verify correct fuel injector resistance.
7. Verify correct throttle position sensor adjustment and resistance.
8. Check for poor quality fuel or contaminated fuel. Check for use of fuel with high alcohol content.

ENGINE LACKS POWER

1. Inspect throttle cable adjustment.
2. Ensure air intake system is not restricted.
3. Test EGR system for correct operation.
4. Ensure fuel system pressure is correct. Use ohmmeter to verify correct fuel injector resistance.
5. Ensure base timing is correct and timing advance system is functional.
6. Test purge control valve operation.
7. Test vacuum switching valve operation.
8. Test throttle position sensor operation.
9. Test coolant temperature sensor operation.
10. Verify throttle valve opens completely when accelerator pedal is fully pressed.
11. Check transmission for correct downshift (A/T).
12. Inspect exhaust system for restriction.

ENGINE MISFIRES OR HESITATES

1. Ensure vacuum hoses are not disconnected or damaged.
2. Ensure electrical harness, connectors, and wires are not broken or loose.
3. Ensure fuel pressure is correct.
4. Test air conditioner switch operation.
5. Test air conditioner power relay operation.
6. Test airflow sensor voltage output.
7. Test barometric pressure sensor voltage output.
8. Test crankshaft position sensor operation.
9. Test coolant temperature sensor operation.
10. Test idle position switch operation.
11. Test ignition switch operation.
12. Test inhibitor switch operation (A/T).
13. Test intake air temperature sensor operation.
14. Test for IAC servo drive signal and operation.
15. Test heated oxygen sensor voltage output.
16. Test power steering oil pressure switch operation.
17. Test throttle position sensor operation.
18. Test camshaft position sensor or cylinder No. 1 sensor operation.

ENGINE RUNS ROUGH ON DECELERATION

1. Test IAC valve for malfunction.
2. Ensure fuel system pressure is correct.

AFTERBURN IN EXHAUST SYSTEM

1. Ensure there are no leaks in exhaust system.
2. Ensure base timing is correct, and timing advance system is functional.
3. Test throttle position sensor operation.
4. Test coolant temperature sensor operation.
5. Test IAC solenoid operation.
6. Test A/C vacuum solenoid valve (if equipped).

POOR FUEL MILEAGE

1. Ensure base timing is correct, and timing advance system is functional.
2. Ensure fuel system pressure is correct.
3. Test air conditioner switch operation.
4. Test airflow sensor voltage output.
5. Test barometric pressure sensor voltage output.
6. Test engine coolant temperature sensor operation.
7. Test idle position switch operation.
8. Test ignition switch operation.
9. Test inhibitor switch operation (A/T).
10. Test injector operation.
11. Test intake air temperature sensor operation.
12. Test heated oxygen sensor operation.
13. Test power steering oil pressure switch operation.
14. Test throttle position sensor operation.
15. Test camshaft position sensor or cylinder No. 1 sensor operation.

DETONATION OR KNOCKING

1. Check engine oil level.
2. Check engine for overheating.
3. Verify base timing is correct.
4. Inspect for vacuum leaks.
5. Test EGR system operation.
6. Check for contaminated or poor quality fuel.
7. Check for carbon build-up in combustion chamber.
8. Ensure spark plug application is correct.
9. Ensure ECM application is correct.

Intermittent Simulation

To reproduce conditions creating intermittent fault, use the following methods

1. Lightly vibrate component.
2. Heat component.
3. Wiggle or bend wiring harness.
4. Spray component with water.
5. Remove/apply vacuum source.

Monitor circuit/component voltage or resistance while simulating intermittent. If engine is running, monitor for Diagnostic Trouble Codes (DTCs). Use test results to identify a faulty component or circuit.