Visual inspection of the MPI/MPFI injection system (Audi A4 B5)

1. Check the air hoses for leaks. You need to check all the hoses - from the thick air intake hose to the small vacuum hose from the pressure regulator.

2. In order of the injection valve gaskets, as well as the gaskets on the suction channel flanges?

3. Additional air enters the intake system through leaky sections, i.e. air that the system cannot take into account in calculations, and therefore the process of preparing the fuel-air mixture is noticeably disrupted. The working mixture becomes uncontrollably leaner. This leads to disruptions in engine operation - mainly at idle.

4. Warm up the engine and then let it idle, open the hood, disconnect the lambda probe connector.

5. Purposefully spray the starting fuel (for example, "Startpilot") suction channel flange gaskets and other suspicious components.

6. If the number of revolutions changes when spraying a certain area, then this area is not sealed.

7. Are there any leaks visible on the fuel lines?

8. Disconnect and reconnect the wire connectors several times. Corrosion and unprofessional jerking can cause damage to the contact.

9. Carefully inspect the connectors of individual injection system units. They can only be treated with contact spray, bending can lead to malfunctions.