Visual control

A leak in the area of the suction system allows the so-called secondary air to pass through. This is air that is not included in the calculations of the control unit and therefore significantly interferes with the preparation of the air-fuel mixture. The mixture leans uncontrollably. The most noticeable disturbances in idling are fluctuations in the number of revolutions. In a loaded engine, this can even lead to ringing.

Check air hoses for leaks. All hoses should be checked, from the thick air intake hose to the small vacuum hose to the pressure regulator.

In the order of the gaskets on the injection valves; as well as gaskets for the flanges of the suction channels?

Through leaky areas, side air enters the suction system, i.e. air that the system cannot take into account, and therefore it significantly interferes with the preparation of the air-fuel mixture. The mixture becomes leaner uncontrollably, resulting in disturbances in the operation of the engine - mainly at idle.

Warm up the engine and to check, run at idle, open the hood. Disconnect the lambda probe connector with the engine off. This disables the lambda probe.

Aerosol starting fuel (For example, «Startpilot») purposefully water the gaskets between the flanges of the suction channels and other suspicious places.

If the engine speed changes after spraying a certain place, then it is not tight.

Are there leaks in the fuel lines?

Have you plugged and unplugged wires multiple times? Corrosion or unprofessional jerking can cause poor contact.

Carefully inspect the connectors of the individual injection components. They can only be treated with contact spray, bending can cause malfunctions.