General description of the fuel system (Audi 80 B3)

The fuel system consists of a fuel tank mounted behind the rear seat, a mechanical fuel pump, and a downdraft carburetor or Bosch fuel injection system. The air cleaner includes a replaceable paper element and, on most models, an automatic air temperature control unit. The exhaust system consists of four parts and, on some models, includes a catalytic converter.

In order not to knock down the fuel system adjustment, in particular the idle speed and CO content, all adjustment screws are equipped with plugs or caps. They must be removed when changing the adjustments. The caps must be crushed, and a hole with a diameter of 2.5 mm must be drilled in the plugs. A screw with a diameter of 3.0 mm is screwed into the hole and the plug is pulled out by it.

When working with the fuel system, it is important to observe fire safety measures. Perform work only in a well-ventilated area. Since fuel vapor is heavier than air, do not perform work in an inspection pit.

[The article was copied from the website audimanual]