Audi 80/Avant (B4)

since 1991-1995 of release

Repair and car operation



Audi 80/Avant
+ Technical specification
+ Engines
+ System of production of the fulfilled gases
+ cooling System
- Fuel tank and fuel pump
   Fuel tank
   Fuel level sensor
   Fuel accumulator
   Toplivoprovod
   Fuel pump
   Replacement of the fuel filter
+ Air filter and airintaking channels
+ injection System
+ Coupling
+ Transmission and transmission
+ Suspension bracket and steering
+ Brake system
+ Anti-blocking system of brakes
+ Wheels and tires
+ Body electrosystem
+ ignition System
+ Lighting
+ Signalling devices
+ Devices and auxiliary devices
+ Heating and ventilation
+ body Elements
+ Search of malfunctions
+ Specifications





Fuel tank

The fuel tank of the Audi 80 car is technically enough perfect, but also it was improved for all-wheel drive models. The difficult form of a fuel tank helps to achieve a high-capacity tank without damage to volume of a luggage compartment. In the middle of a fuel tank you see the fuel pump and the sensor of the indicator of amount of fuel. On the right above a bulk branch pipe with all ventilating and bulk hoses.


Back right wheel niche with the removed podkrylok

1–bulk branch pipe;
2–valve самотека;

3 — a fuel tank;
4 — a broad tank.

The fuel tank in the front-wheel Audi 80 models has capacity about 66 l, in all-wheel drive versions it contains at least 64 l. To reach a flat surface of the bottom of a luggage compartment with possibility of loading of salon, a fuel tank establish in a car stern under the sheet bottom of a luggage compartment. The tank is made of plastic – a material allowing almost unlimited possibilities at giving of a form. These possibilities were used for all hundred percent. For example, the fuel tank of all-wheel drive models occupies practically all free spaces under the body bottom that becomes to achieve probably bigger volume. Therefore the form of this detail of the car looks quite strange. In order that during a trip the parts of a fuel tank located below were emptied also, skillful reception was applied: in this bottom area there is a pump, at the working engine constantly pumping over fuel in located above a part of a fuel tank. And it occurs quite simply: returnable fuel from drain топливопровода picks up additional fuel in the pump case and transfers it upward.

One more reception was applied to cope with chambers of various volume in a fuel tank: the hose conducting directly in area of absorption so it is filled first of all is connected to a bulk branch pipe. It is important, for example, in a case when a small amount of fuel from the spare canister is added.

 Help: before starting to work with system of supply of fuel, you surely should disconnect earthing cable from the storage battery. Inadvertent electric short circuits can serve as the reason of dangerous iskroobrazovaniye.

For what ventilation of a fuel tank is necessary?

  • Ventilation of a fuel tank is important for uninterrupted supply of fuel: in the same quantity in which fuel is spent, in a tank air should arrive, otherwise in a fuel tank the lowered pressure is formed, and intake of fuel will stop.
  • It is necessary to ventilate a fuel tank to give the chance to its contents to expansion when heating.
  • When filling it is necessary, that air could leave a tank because differently poured fuel again will rise to a bulk branch pipe and will start to pour out.

Ventilation of a fuel tank in the Audi 80 car

  • Directly behind a bulk branch pipe the ventilating pipeline of a fuel tank is connected. The ventilating channel conducts at first in the so-called valve самотека. The last closes the pipeline as soon as the car bends aside more than on 45 °. Thus leakage of fuel via ventilating channels is prevented at failures. After passing of the air valve the ventilating pipeline conducts, however, not at once outside, and comes to an end in a tank with absorbent carbon in the right forward wheel niche. Its appointment – to catch fuel pairs passing through this pipeline (arisen, for example, as a result of a warming up of contents of a fuel tank). At the working engine these gases at a certain loading of the engine again are exhausted from a tank with absorbent carbon. When it should occur, defines the electromagnetic valve operated depending on loading.
  • In parallel to this system the air valve opens when filling a broad tank of the fuel tank located in the bulk channel (in the right back wheel niche) in the form of separate capacity. Thus, at increasing level of fuel fuel pairs instead of it to disappear in the atmosphere there can be forced out.
  • During movement on this way external air depending on spent amount of fuel so in a tank it is not formed depression arrives.