E30 fuel gauge issues

[tdk]

Hi all,

First post on this site - I am a e30 owner as of last weekend.

I was wondering if I could get some advice from all you enthusiasts
Unfortunately the fuel gauge has just got stuck at the full position. When I turn the car off it does go down to zero.
I am unsure whether it is the fuel sender (as mentioned in some other posts) or whether it is the gauge itself in the dash.
I am leaning towards it being the fuel sender as if it was the gauge I would assume that it would be stuck in that position permanently?

Any advice on what I could do or where I could get this part for a decent price? (as I believe it is quite an expensive part)

Thanks in advance

[Contours]

I have had this issue a few times and the problem is simply the earth nut on the back of the fuel gauge can work loose over time with vibration so it shows full all of the time. If you tighten this nut with a 7mm socket it will solve this problem. This can also affect the temp gauge which also has a 7mm earthing nut. I was armed with a multimeter and test light to test the sender unit and take resistance readings etc but alas just a loose earth nut causing the whole problem.

[tdk]

Cheers for the response, will give it a go soon

[Brianmoooore]

How much fuel is actually in the tank, and what E30 do you have? There are considerable differences in the fuel tanks and associated senders between small engined saloons and other models.

[tdk]

well I fueled up a full tank last week and before that I assume there was probably about a quarter tank in there. Now there is probably around half maybe but the fuel gauge is still at full. I am going to wait and see if the fuel light comes on as if it does then I don't have be worried too much as I have an indicator as to when I need to top up. I have got a 320i 1990 model.

[Cloggy Saint]

You should make sure the fuel light is working before using this tactic!

[tdk]

yep I have got a small fuel can in the boot just incase the light does not come on and I stop, but hopefully the light comes on!

[Brianmoooore]

If the level sender fitted to the smaller E30 fuel tank is mated to a fuel gauge intended for the larger tank, the gauge will read half when the tank is empty, and will read full for half a tank of fuel and over. Could this be the problem?

[tdk]

could be, thanks for the suggestions. I need to start ruling these out one by one, first I want to see if the fuel indicator light works.

[Brianmoooore]

Low fuel light tends to be very reliable, but it is supposed to come on at a much lower level than most assume. It comes on when the needle of the gauge reaches the part of the dial that actually lights up, not the red painted bit.

[tdk]

thanks for the heads up, will keep that in mind. fuel light hasnt come on yet and car is still running, so far so good haha

[tdk]

So my fuel light does come on so therefore have been able to drive the car with less worry.
I took out the instrument cluster a few days ago to test the brass nut theory and it appears that there is no brass nut or washer behind the fuel gauge. It appears to have fallen out or something as I can see one on the otherside behind the temperature gauge.
This might be a silly question but does it have to be a brass nut or am I able to attach another washer and nut that fits? I went to a few shops nearby and they didn't seem to have any brass nuts/washers so I just came back with a normal silver one. Hopefully this will work?

[Brianmoooore]

As long as it makes good electrical contact it will be fine.

[tdk]

Cheers for that!