strange sender unit??

[swetty]

hi
iv`e got a 68 t2 camper and just finished putting in the 1700 engine.
wiring it all up today got everything working except the fuel gauge..there is no petrol in the tank at all... and the needle on the gauge goes up to just past the red bit (reserve mark )
so i earthed the wire and the needle goes up to full.
next... i took the sender unit out and its a right wierd looking thing...is a plastic tube with a round float that goes up and down inside the tube??on the top of the sender unit it stamped v.d.o and has the vw mark on it..anyone seen one like this before. if i conect it up to the wire and turn it upside down..the needle on the gauge goes to full..so its working.
any ideas...
cheers jon

 

[Araon]

Dont mean to be funny but what you have there is

a T2 sender unit...


were you expecting the boom arm with a float on the end?

 

[swetty]

yes i thought it was a boom arm floaty thing.
so why does the needle on the gauge go to just past the red mark when there is no petrol in it?
the float inside the tube is travelling right to the top and right to the base of the tube.
cheers jon

 

[Araon]

When you pulled it out and tested it was it registering the same or could you get a full sweep on the gauge?

never having opened one up, usually it will be down to a worn rod (forming a variable resistor) in non petro chem environments the use of a HB pencil works wonders recoating the element in carbon, however in a petrol tank its unlikely to work....

but may give a temporary fix whilst you source a new sender....

or the rod could be bent slightly, does it move freely along the full length just that to be registering some fuel then there is a lower resistance to ground than say if the float had reached the bottom of the rod.
or the coil in the fuel gauge is full of shit or kaput...

 

[swetty]

hi
yes it runs freely from top to bottom and bottom to top.
if i connect it up and turn it upside down it registers full on the gauge.
and if i turn it over the right way.. it slides straight down to the bottom registering just after the red reserve red mark on the gauge this is with the sender fitted and not fitted.
strange..when i turn off the ignition the needle on the gauge goes back to empty.
the fuel tank is empty.
cheers jon

 

[cunning plan]

finished putting in the 1700 engine.
wiring it all up today got everything working except the fuel gauge..
so i earthed the wire and the needle goes up to full.

Sorry, doesnt really help with your issue, but im having hassle with the fuel gauge / sender as well (not working at all). If you put the engine in, how did you then get to the sender to take it out? Dont you have to take the engine out to get to the tank?

 

[swetty]

hi
ive got a litle panel that i unscrew above the sender behind the back seat.
all i do is unscrew the screws and there it is.
cheers jon

 

[Araon]

you cheat....