not2oldchevy

Just got new aftermarket gauges and the gas gauge is 240 empty 33 full. My factory one is 33 empty 240 full', is there any way to make it work without changing sending unit?

74modified

Not trying to sound funny, but you could turn the moveable part (potentiometer the float rod is attached to) upside down. Think about it, if the float is on the other side it would reverse the action.

69 Ghost

You can program the PCM to reverse the direction.....

soundengineer

iTrader: (16)

he's not talking about programming the pcm...





the best thing to do is to buy a programmable gauge
Autometer has several series that allow you to set the gauge to work with any sender.

you basically ground out a special calibration wire... usually with a push button...
hit the push button when tank is empty, hit it again when tank is full,...all done...

if you cant get the tank completely empty, but you know your resistance, you can just buy resistors to make the values match and do it that way

its what I did for mine on my camaro....40 ohms empty, 250 ohms full...
I didnt even have to get at the tank to do the calibration

soundengineer

iTrader: (16)

it doesnt work that way either....its just not physically possible

74modified

I guess it just depends on your definition of possible. The bottom one is obviously reversed, and would need the rod bent a small amount. But yes it is physically possible in this case. Would the OPs be this easy? Maybe - Maybe not

soundengineer

iTrader: (16)

ok.. I stand corrected....

not2oldchevy

I have a new tank {empty} but I know nothing about resistors, could you explain? I hate to sound like an idiot but anything electric kills me. Thanks

soundengineer

iTrader: (16)

if you know the resistance at empty, and resistance at full...
then you wont need to involve the tank at all

in your case 240 ohm empty, and 33 ohms full

so go to radio shack and come up with a set of resistors to make 33 ohms, and a second set to make 240 ohms...
the 240 is easy... one 200 ohm and four 10 ohm resistors.. all of them just chaine together in a line
33, I cant think of what there is... but I wanna say you can get an 8 ohm and a 5 ohm and 2 10 ohm resistors to get to 33.

then you just follow the instructions for any programmable autometer gauge.
put the fuel level wire on one side of the resistors, and the other side goes to ground...
hit the calibration wire, and then replace with the other set of resistors... and hit the button again.
once done, throw away the resistors and wire up your fuel sender from the tank to the gauge just like normal

if you dont understand how to do this, then ask some of your friends if they know enough about electrical things to help you, or find a local performance shop to help you out for a few bucks


option 2 which may be easier for you...again, with an autometer programmable gas gauge
just connect your tank fuel level sender to the gauge....and do the calibration with it empty, then fill the tank with gas and do the full calibration....
problem solved and no resistors needed


I mentioned the resistor method because many people on here will buy an aftermarket gauge, and not have the ability to fully empty a fuel tank to do the calibration