Fuel Guage Reads Empty - Not Functioning

[Jimmy535i]

Problem: Fuel guage reads empty - Gas tank is full.

The vehicle in question is a 1990 535iA E34.

I understand this is a common problem also.

I have already read the information available on BMWe34.net and
it looks like the problem may be in the cluster.

If it is in the instument cluster I will probably just leave it alone
and use the trip meter and fill up every 250 miles.

My question is: Has anyone found this problem to be related to
the fuel tank float or sensor in the fuel tank. And if so any advice on how
to fix it.

Thanks in advance and good morning.

[John 535is (Sydney)]

It's not hard to pull the sender unit and check it. Lift the cover in the trunk, disconnect the lines (make sure you mark which is the feed, and which is the return). I plugged the lines temporarily with a short rod to stop any return fuel. Disconnect the harness and remove the unit. You need to jiggle it a bit to get it out. You can clean the 'piano wires' with alcohol. I then filled a canister and checked the float still did its job. I think mine had gone to the bottom and somehow got snagged on the piano wires. Its been working again for 12 months now. Remember - you will be working with an open fuel/gas tank. Take every precuation you can think of, including being in a well ventilated area without kids, pets or mates that smoke.

John 535is 1989

[Jimmy535i]

John: Thank you for the information. I will give this a go.

It should not be to dificult. I am guessing that the float could be hung up like
your case. I will let you know how it works out. I may take some digital
pictures and add them here also.

Yes, I do need to be careful around the fuel tank. Thanks again for the advice.