Table of contents: The engine does not start ↓ Cold engine starts poorly. Runs… ↓ The engine runs with misfires ↓ The engine operates unstably in… ↓ Warm engine won't start ↓
Almost all faults of the electronic injection control system can be found only with the help of special control and measuring devices. Before looking for the cause of the fault, the following conditions for finding and eliminating the fault must be met, namely:
- a) incorrect actions when starting the engine are excluded. Both with a cold and with a warmed up engine, the accelerator pedal should not be pressed when starting the engine;
- b) the tank must be filled with fuel, there is no mechanical damage to the engine, the battery is charged, the starter rotates with sufficient speed, the ignition system is in good working order and adjusted, the fuel system is sealed, there is no contamination in the fuel supply system, the crankcase ventilation is in order, the electrical ground wire (-) (engine - gearbox - body) connected. Print out the fault codes registered by the self-diagnosis system at the workshop.
Caution! Before disconnecting the fuel lines, clean their joints with a cleaning agent or gasoline. Cover the joints with a rag to prevent fuel spillage.
The engine does not start
The fuel electric pump does not work when the starter is running (i can't hear his noise)
Check the voltage supply to the fuel pump. Check the contacts.
Fuel pump fuse defective
Check the fuse.
Fuel pump relay is faulty
Check the relay.
No power to the valve injectors
Disconnect the valve injector plugs. Connect a tester with a control diode lamp to the power wires of the valve injectors and press the starter. The control lamp should flash.
Cold engine starts poorly. Runs unevenly
Coolant temperature sensor or intake air temperature sensor is faulty
Check the sensors.
The engine runs with misfires
Fuel pump power failure
Check the plug connections and contacts of the fuel pump, as well as the relay.
The fuel filter is clogged
Replace the fuel filter.
The fuel pump is faulty
Check the fuel pump and replace if necessary.
The valve injector is faulty
Check the valve injectors and replace if necessary.
The engine operates unstably in transient modes
The air intake system is leaky
Check the air intake system. To do this, leave the engine idling and lubricate the joints and seals of the intake tract with gasoline. If the number of revolutions increases, eliminate the leak
Warning! Gasoline vapors are poisonous. Do not inhale!
The fuel system is leaking
Visually inspect all connections near the engine and electric fuel pump. Tighten all threaded connections.
Warm engine won't start
Fuel system pressure too high
Check the pressure and replace the pressure reducing valve if necessary.
The return hose between the pressure relief valve and the fuel tank is clogged or pinched
Clean or replace the return hose.
(Material republished from the website: AudiManual.ru)