Possible malfunctions of the engine management system, their causes and remedies
| Cause of malfunction | Remedy |
| The starter rotates the crankshaft at normal speed, but the engine does not start for a long time. After starting, the engine stops immediately | |
| Faulty ignition system | Check the voltage in the secondary circuit, the condition of the spark plugs (soot, electrode moisture, cracks or chips in the insulator, the condition of the electrodes and the gap), ignition coils, high voltage wires and protective caps, the reliability of electrical contact in the connectors of the ignition coils, the reliability of the contacts of the computer and the ignition switch with «weight» |
| Faulty fuel injection system | Test the fuel pump relay by connecting a test lamp between terminal «G» diagnostic connector and «weight». The control lamp should burn within 2 with after switching on of ignition |
| The engine does not develop rated power. Vehicle accelerates sluggishly when partially depressing the accelerator pedal | |
| Faulty ignition system | Check the voltage in the secondary circuit with a special tester. Check the operation of the ignition timing system with a stroboscope |
| There is no reliable contact between the computer and «weight» | Check the condition, cleanliness and tightness of the terminal connections «massive» ECU wires |
| Low voltage in the on-board network - the generator is faulty | Check the voltage at the output «B+» generator, which must be at least 13 V |
| Knocking knocks in the engine when accelerating the car | |
| Mismatch of the glow number of spark plugs installed on the engine | Replace the spark plugs with the recommended ones for this engine model |
| Damage to high voltage wires | Check the resistance of the high voltage wires with an ohmmeter. It should not exceed 30 kOhm. An ohmmeter is connected to the tips of the tested wire |
| Malfunction of the coolant temperature sensor or its electrical circuit | Check and, if necessary, replace the sensor. Check the contact connections in the wiring of the sensor circuit |
| Lack of quick engine response to a change in throttle position, especially when starting the car from a standstill and at the beginning of acceleration | |
| Faulty throttle position sensor | Check the freedom of movement of the sensor slider. With an increase in the opening angle of the damper, the sensor signal voltage should increase proportionally |
| Low voltage in the on-board network - the generator is faulty | Check the voltage at the terminal with a voltmeter «B+» generator with the engine running, which should be more than 13 V |
| Faulty intake manifold absolute pressure sensor | Check sensor, wiring connection and sensor vacuum tube installation |
| Faulty high voltage wires | Check the resistance of the wire with an ohmmeter by connecting it to the lugs of the wire under test. Resistance should be no more than 30 kOhm |
| Dirty spark plugs | Clean the spark plugs with a sandblaster or replace |
| Contamination of ignition devices | Remove moisture and dirt from high voltage wires and ignition coils |
| Unreliable contact of ignition devices with «weight» | Check the contact connections of the wires of the ignition system with «weight». Clean and tighten wire lugs |
| The engine runs intermittently. Jerks of the car with increasing engine load. Irregular exhaust noise | |
| Faulty spark plugs | Start the engine. After setting the idle speed, disconnect the idle speed control connector. Remove the high voltage wire from one spark plug using pliers with insulated handles. Disconnect the wires from the candles one by one and for a short time so as not to damage the catalytic converter. If disconnecting the wire from the spark plug does not cause a sharp decrease in engine speed, then the spark plug is faulty and needs to be replaced |
| High voltage wiring fault | Measure the resistance of the wires between the tips with an ohmmeter, which should be no more than 30 kOhm |
| Uneven engine idling, accompanied by increased vibration and stops | |
| Lean air-fuel mixture due to an increase in the voltage of the oxygen concentration sensor signal due to the formation of deposits on the sensor bulb | If there is a white powder coating on the sensor, replace it |
| Throttle stuck open | Eliminate sticky throttle |
| Malfunction of the coolant temperature sensor or its electrical circuit | Check and, if necessary, replace the sensor. Check the contact connections in the wiring of the sensor circuit |