Fuel guage

[rag1873]

Hi, Just bought a C200 today, W reg. Seems like a very nice car!!
However the fuel guage was working fine all day then when i went to the petrol station and filled it up tonight. The guage is not moving now, just sitting at empty as though it isnt working! Any clues as to whats wrong?

 

[whitenemesis]

Did you leave the ignition on while filling up? This can cause the unit to error.

 

[rag1873]

Thanks for the quick reply. No the ignition was turned off and the keys were out.

 

[whitenemesis]

What was the reading before you filled up?

 

[rag1873]

It was sitting at a quarter tank.

 

[wigs_1]

Mine has occasionally done this however turning the ignition on and off seems to do the trick.....

 

[Dieselman]

When the tank is full the float takes the wiper off the rheostat track. As the tank empties a bit it comes back on and will read full then go down with the fuel.

Try a high detergency fuel like Shell, to see if it cleans the track up a bit.

 

[skemball]

An obvious suggestion I know but try giving the tank a clout with your fist from under the car - it just might be a sticking float although this is extremely unlikely as the float will always overcome any stickiness in the hinge mechanism due to mechanical advantage.

Then you are into checking the basics like a sound earth point for the sender. I'm not familiar with any MB fuel tanks but other cars typically have an earth terminal as part of the sender unit casing where it is screwed/fitted into the tank.

 

[lynall]

Did one the other day and as DM says the track was badly worn, but even if it looks okay stick a multimeter across the terminals and move the arm up and down if readings change smoothly all okay.



Lynall