Guest Anonymous Posted April 18, 2003 Share Posted April 18, 2003 Need help diagnosing fuel gauge. I (carefully) dissasembled the float/sensor. All the contacts, and the float surrounded by the thin wire look good, so do the solder connections. When I unplug the two leads to the sending unit, fuel gauge reads empty. When I attatch leads to the sender, it reads full (w/ half a tank of gas). Is there any way to test the sending unit, and the dash gauge ? Thanks Guys!! Jerry 1974 2002 Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted April 18, 2003 Share Posted April 18, 2003 test the sender by moving the float up and down the guide wires while watching the gage. To test the gage I think you'd need to vary the resistance to ground with a variable resistor. Admit I'm not sure it's a resistance gage, some (not BMW?) used capacitance. Anyway, used gage clusters are available for 20 clams 24/7 on fleabay, it might be easier to get another, unless your time is worthless. Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted April 19, 2003 Share Posted April 19, 2003 It should read between about 3-4 ohms when the float is all of the way up to about 80 ohms when the float is all of the way down. Are you saying that the gas gauge reads full with the float in any position? Chris B. '73 ex-Malaga Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted April 19, 2003 Share Posted April 19, 2003 Yes, no matter where the float is at (when I had it out of the tank, but plugged in to the wire loom), the gauge still reads full. Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted April 19, 2003 Share Posted April 19, 2003 Should have asked this before: is your gauge pegged or just reading full? If it is pegged, this means that you have a short in the sensor circuit or a problem with the gauge itself. If it is just reading full, then it may be possible that your float is not making good contact between the wires and is presenting only a light load (meaning, electrical resistance) to the gauge. The latter problem can be fixed by bending the brass tines on each side of the float in a bit so that they make consistent contact with the wire. Obviously, this is a delicate operation, because the wire is easily broken. However, you should first check the sending unit with an ohmmeter to see what is happening with the float in different positions. Chris B. '73 ex-Malaga Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted April 19, 2003 Share Posted April 19, 2003 Thanks guys. I'll get a voltmeter today and test the float. This forum rocks!! Quote Link to comment Share on other sites More sharing options...
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