Engine Controls - Tests W/o Codes: Other Saab 9000 I рестайлинг

ENGINE WON'T START

1. Ensure electrical harness, connectors and wires are not broken or loose. Ensure battery voltage is at least 11.5 volts. Check system relay and fuel pump relay. On turbo models, check pressure switch. Check all ECU input signals.
2. Using a spark tester, ensure that there is spark at the plugs.
3. Ensure fuel pump is operating. Check fuel pressure and pressure regulator. Check for fuel line leaks or restrictions in return line.
4. Check injector operation.
5. Check induction system. Check for leaks downstream of throttle valve. Inspect duct between mass airflow meter and throttle body.
6. Check coolant temperature sensor operation.
7. Check Automatic Idle Control (AIC) valve.

ENGINE STARTS BUT STOPS

1. Ensure electrical harness, connectors and wires are not broken or loose. Ensure battery voltage is at least 11.5 volts. Check system relay and fuel pump relay. On turbo models, check pressure switch. Check all ECU input signals.
2. Check coolant temperature sensor operation.
3. Check induction system. Check for leaks downstream of throttle valve. Inspect duct between mass airflow meter and throttle body.
4. CO too high or too low.
5. Check throttle position sensor.
6. Check Automatic Idle Control (AIC) valve.

ROUGH OR UNSTABLE IDLE

1. Check temperature sensor operation.
2. Check for proper CO setting (if adjustable) on mass airflow meter. Check for broken mass airflow meter filament. Check mass airflow meter resistance.
3. Check induction system. Check for vacuum leaks downstream of throttle valve. Inspect duct between mass airflow meter and throttle body.
4. Check idle speed and EGR valve (if equipped) pulse ratio.
5. Check injector operation and opening duration. Check injectors for leaks.
6. Ensure fuel pump is okay. Check fuel pressure and pressure regulator. Check for leaks in fuel lines or restrictions in return line.
7. Ensure electrical harness, connectors and wires are not broken or loose. Check all input signals to ECU.
8. Check EGR valve (if equipped) for proper operation.
9. Check oxygen sensor.

POOR RESPONSE ON ACCELERATION

1. Check for proper CO setting (if adjustable) on mass airflow meter and for broken filament. Check mass airflow meter resistance.
2. Check induction system. Check for leaks downstream of throttle valve. Inspect duct between mass airflow meter and throttle body.
3. On 900 Series vehicles, check idle speed and pulse ratio.
4. Check injector operation and opening duration. Check injectors for leaks.
5. Ensure fuel pump is okay. Check fuel pressure and pressure regulator. Check for leaks or restrictions.
6. Ensure electrical harness, connectors and wires are not broken or loose. Check all input signals to ECU.
7. Check temperature sensor.
8. Check oxygen sensor.

ENGINE HESITATES OR MISSES

1. Ensure electrical harness, connectors and wires are not broken or loose. Check ECU connector pins No. 9, 11, 13, 17 and 25, and all input signals to ECU.
2. Check charging system for low output and poor ground connections. Check all electrical connections for tightness.
3. Check injector operation and opening duration. Check injectors for leaks.
4. Check turbo and Automatic Performance Control (APC) systems for proper operation.
5. Check throttle position sensor.
6. Ensure mass airflow meter filament is not broken and burn-off function is working.
7. Check induction system. Check for air leaks downstream of throttle valve. Inspect duct between mass airflow meter and throttle body.
8. Ensure fuel pump is okay. Check fuel pressure and pressure regulator. Check for fuel leaks or restrictions in return line.
9. Check temperature sensor.

POOR FUEL MILEAGE

1. Ensure fuel pump is okay. Check fuel pressure and pressure regulator. Check for fuel leaks or restrictions in return line.
2. Check injector operation by unplugging connectors one at a time. Engine RPM should drop noticeably. Check opening duration. Check injectors for leaks.
3. Check coolant temperature sensor.
4. Check throttle position sensor.
5. Ensure mass airflow meter filament is not broken and burn-off function is okay.
6. Ensure electrical harness, connectors and wires are not broken or loose. Check all input signals to ECU.

LACK OF POWER

1. Check induction system. Check for air leaks downstream of throttle valve. Inspect duct between mass airflow meter and throttle body.
2. Check throttle valve for binding and proper adjustment. Ensure throttle valve opens completely.
3. Ensure fuel pump is okay. Check fuel pressure and pressure regulator. Check for leaks or restrictions in fuel line.
4. Check injector operation by unplugging connectors one at a time. Engine RPM should drop noticeably. Check opening duration. Check injectors for leaks.
5. Ensure mass airflow meter filament is not broken and burn-off function is working.
6. Check turbo and Automatic Performance Control (APC) systems for proper operation.
7. Check coolant temperature sensor operation.
8. Ensure electrical harness, connectors and wires are not broken or loose. Check all input signals to ECU.

Intermittent Simulation

To produce the conditions which create an intermittent fault so that it may be identified during testing, some of the following methods may be used

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

Monitor circuit/component voltage or resistance while attempting to reproduce an intermittent. If engine is running, monitor for self-diagnostic codes. Use the results of these tests to identify a faulty component or circuit.