1 - fuel tank; 2 - fuel pump; 3 - fuel filter; 4 - fuel pressure regulator; 5 - adsorber; 6 - ECU; 7 - camshaft position sensor; 8 - ignition coil; 9 - spark plug; 10 - nozzle; 11 - adsorber valve; 12 - air temperature sensor; 13 - air flow meter; 14 - oxygen content sensor; 15 - coolant temperature sensor; 16 - knock sensor; 17 - throttle position sensor; 18 - idle speed control; 19, 20 - to the diagnostics SS; 21 - engine shaft speed sensor; 22 - AB; 23 - ignition switch; 24 - turning on the air conditioner
Sequence of checks when determining faults of the Motronic ECU (DME)
| Sign of malfunction | Sequence of verification |
| The engine does not start | 1. Connection to the ground of the engine and battery 2. Fuses, fuel pump, relay 3. Fuel filter and fuel pump 4. Air duct tightness 5. Wiring and connections of the fuel injection subsystem 6. Nozzles 7. Air flow meter 8. Fuel pressure regulator and fuel pump performance 9. ECU and reliability of connections in its connector |
| 1. Connection to the ground of the engine and battery 2. Fuses, fuel pump, relay 3. Fuel filter and fuel pump 4. Air duct tightness 5. Coolant temperature sensor 6. Idle speed control 7. Air flow meter filter 8. Air flow meter 9. Fuel pressure regulator and fuel pump performance 10. Nozzles 11. Throttle valve, throttle body, throttle valve sticking 12. Wiring and connections of the fuel injection subsystem 13. ECU and reliability of connections in its connector | |
| 1. Connection to the ground of the engine and battery 2. Fuses, fuel pump, injection system relay 3. Fuel filter and fuel pump 4. Air duct tightness 5. Wiring and connections of the fuel injection system 6. Air flow meter 7. Coolant temperature sensor 8. Fuel pressure regulator and fuel pump performance 9. Nozzles 10. Air flow meter filter 11. ECU and reliability of connections in its connector 12. Knock prevention system | |
| The engine starts and stalls | 1. Connection to the ground of the engine and battery 2. Fuses, fuel pump, injection system relay 3. Fuel filter and fuel pump 4. Air duct tightness 5. Wiring and connections of the fuel injection subsystem 6. Idle speed control 7. Throttle valve, throttle body, throttle valve sticking, throttle valve slightly open 8. Air flow meter filter 9. Air flow meter 10. Fuel pressure regulator and fuel pump performance 11. Nozzles 12. ECU and reliability of connection in its connector |
| Unstable engine idling | 1. Idle speed control 2. Air duct tightness 3. Connection to the ground of the engine and battery 4. Wiring and connections of the fuel injection subsystem 5. Throttle valve, throttle body, throttle valve sticking, throttle valve slightly open 6. Coolant temperature sensor 7. Air flow meter filter 8. Air flow meter 9. Fuel pressure regulator and fuel pump performance 10. Nozzles 11. ECU and reliability of connections in its connector |
| Idle speed is not normal | 1. Air duct tightness 2. Connection to the ground of the engine and battery 3. Wiring and connections of the fuel injection subsystem 4. Idle speed control 5. Throttle position sensor 6. Air flow meter filter 7. Air flow meter 8. Coolant temperature sensor 9. Throttle valve, throttle body, throttle valve sticking, throttle valve slightly open 10. Nozzles 11. ECU and reliability of connections in its connector |
| Misfires at idle | 1. Air duct tightness 2. Coolant temperature sensor 3. Air flow meter filter 4. Air flow meter 5. Connection to the ground of the engine and battery 6. Wiring and connections of the injection subsystem 7. Nozzles 8. ECU and reliability of connections in its connector |
| Misfires when driving at constant speed | Air flow meter |
| Engine misfires during acceleration | 1. Air duct tightness 2. Connection to the ground of the engine and battery 3. Wiring and connections of the fuel injection subsystem 4. Air flow meter filter 5. Air flow meter 6. Coolant temperature sensor 7. Fuel filter and fuel pump 6. Fuel pressure regulator and fuel pump performance 9. Nozzles 10. Exhaust gas oxygen concentration sensor (depending on the configuration) 11. ECU and reliability of connections in its connector |
| Unstable engine operation at constant speed | 1. Air duct tightness 2. Connection to the ground of the engine and battery 3. Wiring and connections of the fuel injection subsystem 4. Air flow meter filter 5. Air flow meter 6. Coolant temperature sensor 7. Fuel filter and fuel pump 8. Fuel pressure regulator and fuel pump performance 9. Nozzles 10. ECU and reliability of connections in its connector |
| Unstable engine operation during engine braking | 1. Connection to the ground of the engine and battery 2. Wiring and connections of the injection subsystem 3. Coolant temperature sensor 4. Fuses, fuel pump, injection system relay 5. Throttle position sensor 6. Nozzles 7. Air flow meter 8. Knock prevention system 9. ECU and reliability of connections in its connector |
| Detonation during acceleration | 1. Knock prevention system 2. Wiring and connections of the injection subsystem 3. Air flow meter 4. ECU and reliability of connections in its connector |
| Poor engine response | 1. Air duct tightness 2. Connection to the ground of the engine and battery 3. Wiring and connections of the fuel injection subsystem 4. Throttle position sensor 5. Coolant temperature sensor 6. Fuel filter and fuel pump 7. Air flow meter filter 8. Air flow meter 9. Fuel pressure regulator and fuel pump performance 10. Nozzles 11. ECU and reliability of connections in its connector |
| Increased fuel consumption | 1. Air flow meter filter 2. Exhaust gas recirculation and emission control system valve 3. Coolant temperature sensor 4. Throttle position sensor 5. Idle speed control 6. Wiring and connections of the fuel injection subsystem 7. Air flow meter 8. Nozzles 9. ECU and reliability of connections in its connector 10. Protection and partial load switches |
| Increased CO content in exhaust gases | 1. Air flow meter filter 2. Exhaust gas oxygen concentration sensor (depending on the configuration) 3. Exhaust gas recirculation and emission control system valve 4. Throttle valve, throttle body, throttle valve sticking, throttle valve slightly open 5. Throttle position sensor 6. Coolant temperature sensor 7. Connection to the ground of the engine and battery 8. Wiring and connections of the injection subsystem 8. Nozzles 10. Air flow meter 11. ECU and reliability of connections in its connector |
| Reduced CO content in exhaust gases | 1. Air duct tightness 2. Exhaust gas oxygen concentration sensor (depending on the configuration) 3. Exhaust gas recirculation and emission control valve (depending on the configuration) 4. Air flow meter filter 5. Throttle position sensor 6. Coolant temperature sensor 7. Fuel filter and fuel pump 8. Fuel pressure regulator and fuel pump performance 9. Nozzles 10. Air flow meter 11. Wiring and connections of the injection subsystem 12. ECU and reliability of connections in its connector |
| The engine does not develop full power and does not have sufficient throttle response | 1. Air duct tightness 2. Air flow meter filter 3. Connection to the ground of the engine and battery 4. Wiring and connections of the injection subsystem 5. Fuel filter and fuel pump 6. Coolant temperature sensor 7. Throttle position sensor 8. Air flow meter 9. Fuel pressure regulator and fuel pump performance 10. Nozzles 11. Exhaust gas oxygen concentration sensor (depending on the configuration) 12. Throttle valve, throttle body, throttle valve sticking, throttle valve slightly open 13. ECU and reliability of connections in its connector |
(You can read the original on the website BMWMAN)