The tank is filled, the mechanical part of the engine is in good working order, the battery is charged, the starter rotates at the required speed, the ignition adjustment and the ignition system are in order, the fuel supply system is completely sealed, contamination of the fuel system is unacceptable, the engine crankcase ventilation is in good working order, the electrical ground connection (engine-gearbox-body) reliable.
Caution! If the fuel lines are to be removed, clean them first with a cold cleaning agent.
Cause | Method of elimination |
The engine does not start | |
| Fuse #18 is faulty | Replace the fuse |
| When the starter is turned on, the electric fuel pump does not work | Check the fuel pump |
| Fuel pump relay is faulty | Check the relay |
| Sticking of injection valves | Check the valves, replace if necessary |
| Cold start valve is faulty | Check the cold start valve |
| No signals from the following sensors: coolant temperature sensor, throttle potentiometer, Hall sensor, intake manifold pressure sensor | Check the wiring. Query the control unit memory at the service station |
Cold engine starts but runs rough | |
| CO content is not normal | Check CO content and idle speed |
| Cold start valve is faulty | Check the cold start valve |
| The temperature sensor is faulty | Check the temperature sensor |
| The fuel pressure regulator is faulty | Check the regulator at the service station |
A warm engine starts poorly and runs unevenly | |
| Cold start valve is leaking | Check the cold start valve |
| The air intake system is leaky | Check the suction system: to do this, let the engine run at idle speed, lubricate the seals and connections along the entire suction path with gasoline. If the speed increases, eliminate the air leak |
| Vacuum hose to fuel pressure regulator is leaking | Check the pipeline |
| Injection valves are leaky | Check injection valves |
The engine stalls | |
| The voltage supply to the fuel pump is occasionally interrupted | Check the plug connections of the electrical wiring on the fuel pump and fuel pump relay for reliability. Check the contacts of the fuel pump relay. Clean or replace the contacts |
| Poor fuel quality, bubble formation | Fill up with quality fuel |
| Fuel supply too low | Check the feed quantity |
| The fuel filter is faulty | Replace the fuel filter |
| The fuel pump is faulty | Replace the fuel pump |
| The injection valve is faulty | Check injection valves |
| Throttle potentiometer is faulty | Check the potentiometer |
| The idle speed control valve is faulty | Check the idle speed control valve |
Poor throttle response and unstable engine idle speed | |
| The air intake system is leaky | Check the seal and connections of the suction system |
| Idle speed control is faulty | Check the idle speed control valve and lambda adjustment |
| Throttle potentiometer is faulty | Check the throttle potentiometer |
Hot engine won't start | |
| Incorrect CO content | Check CO content and idle speed |
| Too much pressure in the fuel supply system | Check the fuel pressure at a service station, replace the pressure regulator if necessary |
| The fuel return line between the pressure regulator and the fuel tank is kinked or clogged | Clean or replace the pipeline |
| The engine temperature sensor is faulty | Check the temperature sensor |
| The fuel system is leaking | Perform a visual inspection of all connections in the engine and fuel pump area. Tighten all connections |
| The air intake system is leaky | Check the seals and connections in the air intake system |
The engine runs by inertia | |
| Injection valves are leaky | Check injection valves |
| Cold start valve is leaking | Check the cold start valve |
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