If the fuel gauge is in empty, how many Kilometer than can support the fuel?

I believe I would install a manual rheostat to the tank sending unit and this will allow you to manually test the gauge in the dash.

float level sender in the tank needs adjustment or replacement

1/4 isnt 1/4 ...its at empty
and sender should have the tank low light on

The fuel level sending unit inside the fuel tank is bad or the gauge is or there is a wiring problem This video is for a mercury vehicle , but all makes an models are the same . Repairing Fuel Gauge Problems 2004 Mercury Marquis EricTheCarGuy

It could be the gauge on the dash or the sending unit in the fuel tank is bad. If it is the sending unit ,the gas tank will most likely have to be taken out. And if the dash gauge the dash will have to be taken apart. Diagnosis of Stuck Fuel Gauge Is it Gauge or Sending Unit Here is a video how to test it.

i cant sort this,
the tank does not get full (physically ) at the station pump
the fuel gage shows empty for full or full when empty ?
what?
or MPG low?
or ?

horn won,t blow, backup light won,t come on

It sounds like the fuel sender is bad in the fuel tank.

This is a normal concern.
The instrument cluster uses 4 different operating modes to calculate the fuel level:
Anti-slosh (default mode)
Key OFF fueling
Key ON fueling
Recovery
After a fuel fill up, the time for the fuel gauge to move from empty (E) to full (F) ranges from 2 seconds to 55 minutes depending on which operating mode the fuel gauge is in.
The default fuel gauge mode is called the anti-slosh mode. To prevent fuel gauge changes from fuel slosh (gauge instability due to changes in fuel sender readings caused by fuel moving around in the tank), the fuel gauge takes approximately 55 minutes to go from empty (E) to full (F).
The key OFF fueling mode (2 seconds to read empty [E] to full [F]) requires 3 conditions be met:
The key must be in the OFF position throughout the entire refueling of the vehicle.
At least 15% of the vehicle's fuel capacity must be added to the fuel tank.
The instrument cluster must receive a valid key ON fuel sender reading within 1 second of the key being put into the RUN position. The key ON sample readings are considered valid if the fuel sender reading is between 15 ohms ± 2 ohms and 160 ohms ± 4 ohms.
If these conditions are not met, the fuel gauge stays in the anti-slosh mode, which results in a slow to read full (F) event.
The key ON fueling mode (approximately 90 seconds to read empty [E] to full [F]) requires 3 conditions be met:
The transmission is in PARK (P).
The key is in the RUN position.
At least 15% of the vehicle's fuel capacity must be added to the fuel tank.
In key ON fueling mode, a 30-second timer activates after the transmission is put into the PARK (P) position (automatic transmissions). When the 30-second time has elapsed and at least 15% of the vehicle's fuel capacity has been added, the fuel gauge response time is 90 seconds to read from empty (E) to full (F). When the transmission is shifted out of PARK (P), the fuel gauge strategy reverts to the anti-slosh mode. The key on refueling mode prevents slow to read full events from happening if the customer refuels the vehicle with the key in the RUN position.
Recovery mode is incorporated into the instrument cluster strategy to recover from a missing fuel level input during a refueling event. Missing fuel level inputs result from intermittent opens in the fuel sender or its circuits. Recovery mode (empty [E] to full [F] approximately 20 minutes) is initiated when the following 2 conditions are met:
The instrument cluster is in the anti-slosh (default) mode.
The actual fuel level in the tank is greater than what is being displayed by the fuel gauge

Hi, Sounds like it has a bad fuel gauge sender, location is in the fuel tank.