So after years of suffering a bodgey fuel gauge I'm over it. There's an issue with the circuit I believe bug cannot pin point it.

It works but only half of what it's supposed to. When the tank is full it reads half.

 

It worked properly for a few days when I had a bad earth connection from the loom to the chassis but my head lights didn't work.

 

Has anyone experienced this phenomenon?

Just before I commit to an auto electrician.

 

Also the battery light comes on if I turn on the heater blower. Could these be relAted?

 

 

Battery light coming on with extra load = alternator dying.

 

I wouldnt have thought it would be related to your fuel gauge issue.

 

 

Have you pulled the fuel gauge out of the tank and given it a good clean?

The alternator although under powered shouldn't be the problem as I can turn the wipers, headlights, reverse lights and hazards on and the charge light only just starts to glow.

If I flick the blower fan switch on the charge light is full on.

 

I had a look at the fuel sender unit last week and pulled the cover off. The copper coils look at little worn and black but I'm not touching it because a ke20 fuel sender is rocking horse shit.

 

When I check the voltage at the sender unit I get fluctuation between 0 and 9v.

 

 

hey,

 

I have to have a look at my fuel sender too, apparently its open circuit.. I have a few shells around so if you get stuck for a sender hit me up.. cars are out near dalby, I'm at gowrie junction ;)

 

could it be a bad body earth? bloody 40 year old electrics :down:

Some simple diagnosis should help rule out a few things.

 

Check voltage at the battery with the heater fan off versus on for voltage drop over the entire system.

 

Check voltage drop between the negative battery post and the chassis & block

 

Check for voltage drop at the fuel sender / tank earth and the gauge relative to chassis

 

Check the sender voltage with a full and empty tank to see if you get full output.

 

Unfortunately visual inspection and half-truths really don't go far with electricity, but there are very few variables in cars as simple as this so with proper measurement you'll narrow it down pretty quickly.