Originally Posted by Turbo_Steve
I think i could do it with a PIC chip. I think it would have enough internal memory not to need another eeprom chip for a seperate table. If we keep it simple i could make the tank have 255 correction points i think. Once we have mapped one car it can be programmed into all of them. The chip only costs a couple of quid. Could probably make a circuit board and enclosure ready to go all in for maybe £30-£35 ish.
I will probably be doing it for mine anyway as the gauge really makes me feel guilty lol so i will post any results if i manage to get it working.
Winding the rheostat as a real hit and miss affair. I have a friend who worked for delphi and they had a master calibrator gauge that they used the data for a cnc winding machine to make the coil variable spacing very accurately. I could probably do it on the cnc lathe but i don't fancy that as a job. Probably be a real pain getting it right.
A easier solution might be to experiment with a few resistors soldered to the other side of the rheostat coil in tactical places to 'trim' the winding. You could leave the original coil intact. perhaps variable resistors could be used and tweaked to get the settings then change them for fixed values once measured. I do think the electronic method is easier though.