Fuel gage question ?????

[Mud Rookie]

I know that this question is going to get ALOT of laughs but I am trully stumped.

I hit a pot hole yesterday coming home from work and my gas gage needle went from half a tank right up to and pass the FULL indicator..... About 15 minutes later I noticed that it had gone back to showing me exactly how much gas was left in the tank which was about half.... I pull into my driveway and the damn thing was stuck on FULL again.... What the hell...

Is it electrical ?
Is it the actual gage ?
Is it...

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[Joust]

in short its electrical. probably a corroded wire.

A fuel gauge is is basically an OHM meter. the sending unit has a float on an arm. the arm is attached to a potentiometer that varies resistance depending on the arm position.
Some can go from low resistance to high and others its reverse. Id guess that yours goes low resistance (empty) to High resistance (full). therefor if the wire is broken this equals infinite resistance so your gauge is off scale.

I know my Chrysler uses 1035ohms (empty) and zero (full) . there is carbon deposits in the wiper so the highest resistance it gets to is 750ohms. this result is my gauge shows 1/8th of a tank when its bone dry.

my ?
Joust

 

[Mud Rookie]

Thanks for you information

But I am still not sure what and or how to fix it... Does anyone know anyone that they can refer me to that can help me out with this. Its driving me nuts and it just happend yesterday....

I am still fairly new to this area and still do not have a friendly in town mechanic who isn?t going to charge me up the butt and take all my money for even the simpliest of jobs..

Any suggestions ?
Any names ?

Can I fix it myself.. ?

If so then what is the process ?

Thanks again for everyones help

Danny

 

[Joust]

now comes the tedious task of tracing wires.
this can be very time consuming.
I'd wait for fair weather. find a good service manual with good wiring diagrams.

 

[Richard]

Well, the most likely places are at connectors. At the tank is hard to get to as you have to drop it, so keep that for later. I think it would be behind the gauges. YJs have a really cheap connector for the gauge cluster; it's a thin flexible plastic with copper laid on it. The copper corrodes easily, so there's a good chance it's that. Might also affect the gauge lights there.

The hardest part of taking the gauge cluster off is you have to take the radio out first. After that just look for the screws. A service manual will show you all this.

Good Luck.

 

[Mud Rookie]

Thanks everyone for you help... I will look for the possible broken cable behind the instrument gage and if is not there then I will wait for the summer to play with the tank...

Much appreciated...

Danny