What if the gas indicator gauge is not accurate It jumps to a different spot when the engine is turned on Is this electrical and can you do anything about it?

Answer 1

To provide an accurate reading of the gas in your tank, the dash gauge relies on a stable power supply voltage and a relatively slow changing linear variable voltage proportional to the liquid level in the tank. Problems with either will result in misleading readings. Because the power supply in a car will vary between about 12.4volts and 14.5 volts it is usually not stable enough to supply the gauge. Instead the instrument gauges (gas, temperature, oil) receive their voltage supply from a stabiliser unit (generally mounted at the back of the instrument cluster). If this unit develops problems one or more and sometimes all guages will behave erratically. The gauge receives a voltage signal proportional to the tank liquid level from a sending unit (sensor) located in the tank itself. To test.....locate the supply wire from the sensor to the gauge. Ground (earth)this wire temporarily. Switch the ignition key on. The dash guage should indicate a full tank. If it does then the problem is with the tank sensor. If the gauge does not indicate 'full' then the problem lies with the guage end of things and not the tank sensor. If all other dash gauges are behaving normally the problem is most likely the fuel guage itself. If any other guage is reading erratically in addition to the fuel gauge the problem is most likely the voltage stabiliser, but don't forget to first look for more obvious problems like loose or dirty wiring connections. Hope this helps.....if more info needed, email me at seahog@btinternet.com