Fuel Gauge weirdness

[jockduck]

Hi, This only involves cars where the fuel gauge is mounted in the speedo ie early minis, I noticed that my fuel gauge read more or less correctly while the car was at rest but the indicated level dropped almost in line with increase in car speed, the fuel level would return to correct when the car stopped. I played around with the tank sender and even made an electronic instrument voltage stabilizer all to no avail so I pulled the speedo and checked the fuel gauge which seemed normal. I then had a thought about what could affect the working of what is a hot wire voltmeter and found that blowing air on the wire coil caused the reading to drop. So! I glued a small piece of plastic to act as a wind shield, I have surmised that the rotating disc of the speedo was creating wind like a small fan and cooling the fuel gauge.
Since doing the mod my gauge is much better, the reading drops slightly at normal road speeds with recovery when stationary, the drop in reading is only 10% of what was seen previously.
Has anyone else suffered from dropping readings in their fuel gauge?
Jock

[notamini]

That is so bizarre! Kudos for your resolve. I wonder if a ribbon speedo would sometimes get the same problem. I believe the fuel gauge relies on a voltage regulator module in my car but I don't know if it uses a 'hot wire' voltmeter cct. If I get a chance, I'll look it up.