[jeffmc]

Hello All
My gas gauge is acting like a voltage gauge !! My higher my rpm are the father toward full the gauge goes.
I think its the sending unit ,when I got this car the sending unit was already installed. Dave (the guy who started the car project ) was planning on putting in an electronic gauge . I never got any paper work for the gauge ( Dave passed away ,and I got the car from his estate ) So I didn't use the electronic gauge ,and put in a gauge from auto zone .
Question one
Do I need to change the sending unit and the gauge at the same time ? Can I just change one or the other . Are there special gauges and sending unit for electronic set up?
Question two
Is all gas tank holes (the hole that the sending unit goes in) the same size .
I seen some sending units and gauge packages on eBay ,but do not know if the sending unit will fit .If the tank holes are the same size I can solve this problem easily .

Thanks

Jeff

P.S.
I am ready to finally ready to tag this car after three years !!!
Its a 41 dodge D19 ,with a 302 ,auto trans

[dsraven]

if you have an analog gage, then it works on the principle of magnetism. if you could imagine inside the gage there are two little coils with the gage needle between them. one of those coils is connected to the battery through the ignition switch, and ground on the other end, so it is a constant electromagnet. the other coil is connected to the battery in the same way as the first, except for a ground it goes to the rheostat in the sending unit-in tank- which gives a variable amount of ground depending on how much fuel is sensed. more fuel gives more ground which gives that second little coil more magnetism, which pulls the gage needle closer to the full mark. less ground in the sending unit would let the first coil overpower the second coils magnetism and the gage needle would go closer to empty. if your gage is reading funny as you rev up the car, then you are probably experiencing a voltage fluctuation, which causes a fluctuationin how much magnetism those little coils are putting out. try putting a volt meter across the battery and rev the engine up some. see how much the voltge changes. was your vehicle originally a 12v system or was it converted? sometimes the converted vehicles will have a resistor to drop the votage for gages etc. a voltage fluctuation may cause a bigger fluctuation when dropped through the resistor. also check for a bad ground in the dash cluster ground.
have fun and keep us posted
dsraven