Petrol gauge problem

[GolfMad]

Car seems to be running fine, but lately have noticed that petrol gauge once down to about quarter full rapidly falls away to well within the red section within a very short space of time.  I can drive the car a bit and the needle can creep back up to above the red.  I am getting about 27/28mpg around town and over 31mpg on longer runs which seems pretty good to me.

Therefore my questions is does anybody have any thoughts on what the problem might be - dodgy gauge, sender unit??

Any help appreciated, cheers Andy

[bored_Welsh_lad]

Earthing issue maybe?? losing some of the voltage signal and therefore poor readings?

[gtitdi]

i have exactly the same thing with mine - i just keep it filled up - that cures it!!

[kr1s77]

i think it may be a reserve in the tank

[firstgolfgti]

I've recently had this problem on my GTi. After a day it had sorted itself out and hasn't touch wood happened again.

I just checked all visible earth points for any corrosion and also the connector on the fuel pump/sender in the boot.

[adyh]

Where is the earth point for the Fuel Tank Sender ?

[Rmachines]

Yea i need to find my earth point

Mine has been stuck on the white mark just above the red, i put £15 in yesterday and it didn't move 

[kt_gti]

I had kinda the same problem one minute the fuel guage was working fine the next i had no petrol at all well according to the damn gauge i didnt. Then the other day the gauge stopped working completely for two days and knew it couldnt be the clock coz it wasnt changed not that long ago but theres a sensor on the side or on the top of the tank that links into the float inside the tank that tells you how much petrol youve got. Mine just randomly started working again but was advised that either dodgey earth connection or broken sensor could cause this. The other thing that happens with mine when going along a bumpy road think the float in the tank may be sticking. 

[firstgolfgti]

I never found the earth point for the sender but according the the haynes manual its E196(haynes ref) and the description is 'rear loom earth' or words to that effect. This is a main earth point for most things on the rear loom. I generally checked every visible earth point and replaced any that had corrosion

Traced the loom as far as to the point it goes under the rear seats, visible when they are folded down.

I would think that in theory you could attach a temporary earth from the nearest earth point or the even the battery negative terminal to the earth wire of the plug on the fuel pump/sender unit in the boot. Either hold it in there or make a junction, and if you remove the parcel shelf you should be able to see the guage at the same time to see if it has any effect.

Sorry I can't be more precise with earth locations.