Engine Controls - Tests W/o Codes: Other Kia Sephia I рестайлинг

CRANKS NORMALLY BUT WILL NOT START

1. Check for spark.
2. Check fuel system pressure.
3. Check fuel injector operation.
4. Check engine compression.
5. Check timing while cranking.
6. Check coolant temperature sensor.
7. Check condition of spark plugs.

CRANKS NORMALLY BUT DIFFICULT TO START

1. Check PCM ground and power circuits. See COMPUTERIZED ENGINE CONTROLS in «SYSTEM/COMPONENT TESTS»(ref-25100) article.
2. Check intake manifold vacuum. Vacuum should be more than 17.7 in. Hg at idle.
3. Check start signal. See COMPUTERIZED ENGINE CONTROLS in the «SYSTEM/COMPONENT TESTS»(ref-25100) article.
4. Check air filter element.
5. Check exhaust backpressure.
6. Ensure fuel system pressure is correct.
7. Check Idle Air Control (IAC) valve. Refer to «SYSTEM/COMPONENT TESTS»(ref-25100) article.
8. Check ignition timing (1.6L, 1.8L).
9. Check engine compression.
10. Check for contaminated mass airflow sensor.

ROUGH OR UNSTABLE IDLE

1. Ensure PCM terminal voltages are okay. See «PIN VOLTAGE CHARTS»(ref-25101) article.
2. Use stethoscope to verify fuel injector operating noise.
3. Check condition of spark plugs.
4. Check cylinder balance.
5. Check air filter element.
6. Ensure fuel system pressure is correct.
7. Check for contaminated mass airflow sensor.
8. Check for air intake leaks.
9. Check EGR valve.
10. Check engine compression.
11. Check EVAP operation.
12. Check ignition timing (1.6L, 1.8L).
13. Check PCV valve.
14. Check engine coolant temperature sensor for correct resistance.
15. Check Idle Air Control (IAC) valve. Refer to «SYSTEM/COMPONENT TESTS»(ref-25100) article.
16. Check for cracks and poor connections (vacuum leaks) at airflow meter.
17. Check oxygen sensor for fluctuating 0.1-1.0 volt output while increasing and decreasing engine RPM. Refer to «SYSTEM/COMPONENT TESTS»(ref-25100) article.
18. Verify Throttle Position (TP) sensor has correct adjustment and resistance value. See «ADJUSTMENTS»(ref-25084) article.
19. Check closed throttle position switch (1.6L).
20. Check purge control solenoid valve function.
21. Check fuel for poor quality or contamination.

HIGH IDLE AFTER WARM-UP

1. Check for vacuum leaks.
2. Ensure PCM terminal voltages are okay. Refer to «PIN VOLTAGE CHARTS»(ref-25101) article.
3. Check PCV valve.
4. Check throttle cable adjustment.
5. Check ignition timing (1.6L and 1.8L).
6. Check Coolant sensor.
7. Check Throttle Position (TP) sensor. Refer to «ADJUSTMENTS»(ref-25084) article.

ENGINE STALLS ON DECELERATION

1. Check idle condition. If vehicle does not idle properly, see «ROUGH OR UNSTABLE IDLE»(ref-25095-S02045038542001010500000) .
2. Ensure PCM terminal voltages are okay. Refer to «PIN VOLTAGE CHARTS»(ref-25101) article.
3. Check for poor connections at ignition coil, ignitor, distributor, high tension leads, Throttle Position (TP) sensor, airflow sensor, crankshaft position sensor, camshaft position sensor, injectors, fuel pump relay and PCM.

ENGINE STALLS INTERMITTENTLY

1. Check idle condition. If vehicle does not idle properly, see «ROUGH OR UNSTABLE IDLE»(ref-25095-S02045038542001010500000) .
2. Ensure PCM terminal voltages are okay. Refer to «PIN VOLTAGE CHARTS»(ref-25101) article.
3. Check for poor connections at ignition coil, ignitor, distributor, high tension leads, Throttle Position (TP) sensor, airflow sensor, crankshaft position sensor, injector, fuel pump relay and PCM.
4. Perform «INTERMITTENT PROBLEM DIAGNOSIS»(ref-25095-S39757689052001010500000) under INTERMITTENTS.

ENGINE HESITATES OR STUMBLES ON ACCELERATION

1. Check intake manifold vacuum. Vacuum should be more than 17.7 in. Hg at idle.
2. Check air filter element.
3. Check for restricted exhaust system.
4. Check fuel filter.
5. Ensure PCM terminal voltages are okay. Refer to «PIN VOLTAGE CHARTS»(ref-25101) article.
6. Verify Throttle Position (TP) sensor has correct adjustment and resistance value. See «ADJUSTMENTS»(ref-25084) article.
7. Ensure fuel system pressure is correct.
8. Check ignition timing (1.6L and 1.8L).
9. Check mass airflow sensor. See «SYSTEM/COMPONENT TESTS»(ref-25100) article.

ENGINE SURGES WHILE CRUISING

1. Verify Throttle Position (TP) sensor has correct adjustment and resistance value. See «ADJUSTMENTS»(ref-25084) article.
2. Check oxygen sensor. See «SYSTEM/COMPONENT TESTS»(ref-25100) article.
3. Check throttle linkage operation.
4. Check intake manifold vacuum. Vacuum should be more than 17.7 in. Hg at idle.
5. Check air filter element.
6. Check EGR operation. See «SYSTEM/COMPONENT TESTS»(ref-25100) article.
7. Check ignition timing (1.6L and 1.8L).
8. Ensure fuel system pressure is correct.
9. Check for restricted exhaust system.
10. Check fuel filter.

LACK OF POWER

1. On M/T models, ensure clutch is not slipping.
2. On A/T models, ensure transmission is not slipping.
3. Ensure brakes do not drag.
4. Ensure tire size and air pressure are to specification.
5. Check throttle linkage operation.
6. Check EGR operation. See «SYSTEM/COMPONENT TESTS»(ref-25100) article.
7. Check ignition timing (1.6L and 1.8L).
8. Ensure PCM terminal voltages are okay. Refer to «PIN VOLTAGE CHARTS»(ref-25101) article.
9. Check intake manifold vacuum. Vacuum should be more than 17.7 in. Hg at idle.
10. Check air filter element.
11. Ensure fuel system pressure is correct.
12. Check Mass Airflow (MAF) sensor. Refer to «SYSTEM/COMPONENT TESTS»(ref-25100) article.
13. Check spark plug condition.
14. Check spark plug wires.
15. Check ignition coil resistance.
16. Check engine compression.
17. Check for restricted exhaust system.
18. Check fuel filter.
19. Check for contaminated fuel.

ENGINE RUNS ROUGH ON DECELERATION

1. Check intake manifold vacuum. Vacuum should be more than 17.7 in. Hg at idle.
2. Check air filter element.
3. Ensure PCM terminal voltages are okay. Refer to «PIN VOLTAGE CHARTS»(ref-25101) article.
4. Verify idle speed is correct.
5. Check engine coolant temperature sensor. Refer to «SYSTEM/COMPONENT TESTS»(ref-25100) article.
6. Check oxygen sensor. See «SYSTEM/COMPONENT TESTS»(ref-25100) article.
7. Verify Throttle Position (TP) sensor has correct adjustment and resistance value. See «ADJUSTMENTS»(ref-25084) article.
8. Check Mass Airflow (MAF) sensor. Refer to «SYSTEM/COMPONENT TESTS»(ref-25100) article.
9. Check for leaking fuel injectors.

FUEL ODOR

1. Check fuel evaporative control system. See FUEL EVAPORATION under EMISSION SYSTEMS & SUB-SYSTEMS in «SYSTEM/COMPONENT TESTS»(ref-25100) article.
2. Check purge control solenoid valve. Refer to the appropriate «SYSTEM/COMPONENT TESTS»(ref-25100) article.
3. Check fuel system.

EXCESSIVE OIL CONSUMPTION

1. Check for restricted PCV system.
2. Check for leaks.
3. Check for worn engine parts.

POOR FUEL MILEAGE

1. On M/T models, ensure clutch is not slipping.
2. On A/T models, ensure transmission is not slipping.
3. Ensure brakes do not drag.
4. Ensure tire size and air pressure are to specification.
5. Check alignment.
6. Check for restricted exhaust system.
7. Ensure all vacuum hoses are connected correctly.
8. Check intake manifold vacuum. Vacuum should be more than 17.7 in. Hg at idle.
9. Check air filter element.
10. Check spark plugs.
11. Check compression.
12. Ensure PCM terminal voltages are okay. Refer to «PIN VOLTAGE CHARTS»(ref-25101) article.
13. Check ignition timing (1.6L and 1.8L).
14. Ensure fuel system pressure is correct.

Intermittent Simulation

To reproduce conditions creating an 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 self-diagnostic codes. Use test results to identify a faulty component or circuit.