Fuel indicator full while tank is empty

[zago]

There are some posts about tank and sender problems but not exactly related with my problem.
Bought second hand fuel pump ( 1.4l petrol BBY engine) instantly noticed that indicator shows full tank whil it isnt. Today filled full tank to check and indicator shows empty tank, and started to beep that its empty. So indicator shows totally opposite tank measurement. Does anyone knows where the problem is?

 

[A2Steve]

It means that you've been sent the opposite size fuel sender. If you've got the 35 ltr tank and been sent a 42ltr or vice versa then the sender reads opposites.

 

[zago]

So in this case I must buy normal sender that fits my tank. My tank is 42L so looks like second hand sender was from 35L tank and that is the main problem.
Thank you !

 

[zago]

Is it possible to take few electronic parts from 42 l tank sender and put in 35l tank sender?

 

[kp 115]

Is it possible to take few electronic parts from 42 l tank sender and put in 35l tank sender?

Not recommendable messing within electronics near/in fuel tank.

 

[audifan]

Sounds to me more likely the unit sent is older than the one in your car and is now reading in reverse due to the change Audi made. Dash and tank are no longer compatible.

Were the part numbers of the original unit and the replacement unit identical?

 

[Robin_Cox]

the 7zap diagram linked to here cites the part numbers for early and late sender components for both petrol and diesel engines. They are hidden but if you click or mouseover the hidden link it is made visible as the URL.

fuel delivery unit and sender for fuel gauge Audi A2 (A2) 2003 year Audi EUROPA 919030

fuel delivery unit and sender for fuel gauge Audi A2 (A2) 2003 year Audi EUROPA 919030 spare parts

audi.7zap.com

 

[zago]

Find article here as well

Fuel gauge issue

Hi all. Another problem to ask about. I changed my in tank fuel pump a while ago and since then, my fuel gauge was reading the opposite of what it was. I read it’s something to do with the resistance being slightly out. I filled my tank up completely to the brim and the needle went straight to...

www.a2oc.net

 

[zago]

Bought new pump ERA 775048A with 3bar. The fuel indicator works in reverse way again. Does anyone knows what pressure original VDO pump 8Z0919051C has? 3bar or 4 bar?
The same question with 8Z0919051A ?

 

[2work]

Afternoon Zago,

All you need is the correct fuel pump with the correctly matched(to the instrument cluster) fuel sender. Graham @audifan said this back at Post #6 which I am inclined to agree with. Have knowingly gone through this before myself and a swap to the correct fuel pump/sender resolved the issue instantly.

Use Robin’s @Robin_Cox information at Post #7 to obtain the right item required.

Kind regards,

Tom

 

[zago]

After changing pump indicator is ok but petrol consumption over 8,8ltr/100km.