Fuel gauge

[1980CJ-7]

I'm having trouble with an aftermarket fuel gauge..1980 cj 7..I read somewhere about calibrating. Is this necessary and how would I do it. I have recently installed a new sending unit as well.

 

[TLCJ5]

Exactly what kind of "trouble" are you having? Does the fuel gauge work at all?...is it inaccurate?...When you installed the sending unit was it straight & is it reaching all the way to the bottom of the tank?

 

[1980CJ-7]

Exactly what kind of "trouble" are you having? Does the fuel gauge work at all?...is it inaccurate?...When you installed the sending unit was it straight & is it reaching all the way to the bottom of the tank?

I'm not sure if it goes to the bottom or not. Its a crown replacement. For a 15 gallon tank. The gauge reads below E when I hook up the power. I know it's 12 volts. I traced out the only wire reading ohms and assumed that's the sending unit wire. It's same color and reading same ohms at rear near tank and in front at gauge. I dont remember the readings exactly but I do believe it was milliohms and not ohms. Or something like. I can't say exactly when I get home. But that's a summary of my issue.

 

[TLCJ5]

If the tank is full & you're reading below E then I would say your polarity on the gauge is wrong...I've heard of that with after market gauges.
Here's the resistance readings you should get from the sender.
Empty tank=73ohms
1/2 tank=23ohms
Full tank=10ohms

Hope that helps!...let us know what you find.

 

[SteelHeadz]

What type of fuel gauge are you using?.It has to meet the specifications that Tom posted otherwise it will not be accurate.

 

[1980CJ-7]

If the tank is full & you're reading below E then I would say your polarity on the gauge is wrong...I've heard of that with after market gauges.
Here's the resistance readings you should get from the sender.
Empty tank=73ohms
1/2 tank=23ohms
Full tank=10ohms

Hope that helps!...let us know what you find.

It's an equus gauge. I'm ready 9 M-ohms. It's jumps around a bit. I noticed it's only when the power is on or hits the contact the gauges falls. The gas level has changes but I'm no sure the gauge has. Just put it in not too long ago and front axle is apart so it'll be a while before on full although I do run it...idle.

 

[1980CJ-7]

It's reading 193 k ohms

 

[TLCJ5]

If your reading 193K ohms from your sending unit to ground I think you have a wiring issue or a bad sending unit(I know it's new,but...) anyway back track towds the sending unit...get as close to it & see what kind of reading you get.