autometer fuel gauge PROBLEM!!!

[dusterboy15]

OK so i have a tach already, so i thought all i have to do is splice into my tach wires to hook up my fuel gauge. I did that, but when i go to turn my lights on the fuel gauge pegs to the black metal screw past fuel and it pegs REALLY fast, but then when i turn the lights off it goes back to the correct spot marking how much gas i have. I have no clue whats going on.

I have the the Igniton wire off the fuel gauge connected to the Red wire off the tach. The White wire for the lite bulb is run to the white wire on the tach. Then the ground off the blub is spliced into the wire of the fuel gauge then spliced into the ground off the tach. And then the Sending unit wire off the fuel gauge is ran all the way to the gas tank, to were the stock hook up was.

I have no idea why when i turn the lights on the gauge pegs and then when i turn it off it's fine. Do i have to run the Ground off the light blub to a seperate ground or what? All help welcomed

[Dart67]

See if this helps any.

http://www.autometer.com/download_instruction/247e.pdf

Herb

[dusterboy15]

a little the only thing is my gauge has 2 wires on the light

[68dodge]

The ground from the light has to be grounded to the car, the fuel gage ground goes to the tank sending unit.

[sunsetdart]

Make sure the sending unit is matched up to the gauge. Mopar,Chevy, Ford all take different amps for their sending units and so the gauge must have the correct amp too.

[dusterboy15]

thats it the gauge has to ground to the gas tank and the light to its own ground, but where on the gas tank do i ground the wire? it only has a ground strap

[sunsetdart]

A ground is a ground. The gauge doesnt have to be grounded to the tank. A common ground will work for whatever you need to ground.

[dusterboy15]

is a ground from the chasis different from a straight ground to the battery?

[sunsetdart]

if the battery is grounded to the block ,then there is no difference

[68dodge]

A ground is a ground. The gauge doesnt have to be grounded to the tank. A common ground will work for whatever you need to ground.

If you run a fuel cell you need two wires to the tank sending unit, one is the ground from the Gage.

[dusterboy15]

nope no fuel cell, i just dont know whats causing it to do that, maybe ill just run it with out the lights or sumthing iono

[68dodge]

nope no fuel cell, i just dont know whats causing it to do that, maybe ill just run it with out the lights or sumthing iono

Is you gage mounted on metal or a plastic ? You may need to run a ground wire to the gage mounting stud. Take a test light, put the end on a ground area and touch the gage metal case. if the light comes on you may need a ground or you have a short somewhere. If this does not work, the gage may have the wrong ohms for your sending unit.

[dusterboy15]

its the correct gauge, its the one for ford and chryslers but maybe i need to run my igniton wire from somewere else

[dusterdoug]

 
I think you have it wired backwards. The sending unit is variable resitor. The power goes into it and the sending unt/float determines how munch amperage is sent to the gauge, then the gauge is grounded.  The reading comes from how much elelctricity is coming from the sending unit/float in the tank