Hello everybody


Right, I am now about to dispair and give up unless someone can help me with this problem I have....

The fuel guage is not working correctly.

The sender wire is new, the connections are new and it is not shorting out!
The car has been converted to negative earth at some stage

Ok this next bit is what confuses me....

When you switch on the ignition, the fuel guage rises to the "full" position
(at present there is about a 1/4 of a tank of fuel in there)

I took the sender unit out to see if it was this that was playing up.
when the body of the sender unit is earthed to test it, and I move the arm with the float on it, the guage works fine as it should do.

When I put the sender unit back in the tank and connect it all back up again, the needle just goes straight to the "full" position again.

I have narrowed it down to this:

When the sender unit is in the tank and the sender body is earthed on the tank, the needle goes up to "full"
when the sender unit body is NOT earthed, the needle does not move at all, dispite the float moving with the fuel in there.

Also it is impossible not to earth the sender body to the tank, as the retaining ring is made from metal.


Hopefully I havent confused you....

By the way its a series 3


Any help much appreciated.

Many thanks
Alex

There is only one answer, when you fit the sender to the tank something is shorting out the sender. You just need to confirm this with a test meter, and then find out what is causing it.

Simple

Hi, Thanks for the quick reply.

Im not sure what it could be shorting on? the clip that holds the sender unit in place is metal and that wil then earth the sender unit to the tank.

Would it short if the float was touching something? as the float and rod are also made of metal...

Also now the temperature guage does not work, this also gets a feed in from the voltage regulator as does the fuel guage....

Cheers
Alex

Hello Again people...

Update:

ok, ive found the problem.....

Me being a silly boy didnt realise that the tank that has the sender unit in it was full of petrol! Hence why thy guage rises straight to the top....

However... this leads me to another question....

The passenger side tank (with the sender) was full to the brim almost, however the drivers side one only showed about a quarter of a tank, hence why i only thought there was a 1/4 of a tank of fuel.

Shouldnt the levels be about the same in the 2 tanks? Why would the passenger side one be full and the other almost empty?

Blocked pipe?

Help please

Many thanks
Alex

Both tanks are linked via large tubes that join in the centre, at the back of the boot. This is where the fuel take-off pipe joins. I dont know how such a large tube could be blocked, and whats more, since the fuel is put in on the drivers side, how did the fuel get to the passenger tank with out filling the drivers one first? Are you sure the LH tank is nearly full?

There is also a small rubber breather pipe running across the top between the tanks. This often perishes and causes a petrol smell.

I think you may need to pull the tanks and check all pipes etc.

PS: Putting your car series # in your signature help with replies.

Thanks for the help

I have drained the petrol tanks, and in doing so I managed to fill a 20 litre fuel can and 2 small 5 litre cans!

i'll whip the tanks out hand have a look, will give them a lick of fresh paint whialst I have them out as well I think.

Next challenge is to get that big pipe undone, the jubilee clips look as if they have seen better days, will refit with some new ones as well.

I'll keep you updated