Petrol Gauge Problem

[Nax]

Hi,

Just wondering if anybody might know what would cause my petrol gauge to read empty even when I know the car is full.

My car is a '94 320i and has had only a few minor problems since I got it a few months ago.

I thought that maybe there was no power getting to the sender units, but I checked them with a multimeter and both have a constant 12 volts when the ignittion is turned on. I also checked the circuit in the sender unit and found that there are no breaks in it.

I was wondering if anybody knew which of the senders was the main one that sends to the gauge, or if they work on an average between the two.

also if anybody knows exactly what amount of resistance the sender should have when the tank is full, as this appears to be the best way of checking if there is a fault.

Otherwise I am guessing I will have to fork out the $$$'s to an autoelectrition and still not know if he can fix it.

Thanks in advance

Nax

 

[Nax]

After a bit of ringing around, I got hold of an auto electrition who told me to try and disconnect the battery for a couple of minutes and then see if the gauge worked when I reconnected it.

Unfortunately, or more to the point fortunately, my gauge started working the next time I got in the car before I had a chance to try disconnecting the battery, so I don't know if it works or not. Figgured I would post this here just in case somebody else ever gets the same problem.

Nax