fuel gauge

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DARTLARRY

DARTLARRY

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I am working on an old chrysler. And the fuel gauge reads full all the time, as if it were grounded. I have checked all the wiring, and it seems fine. what else could I be missing? The gauge obiviously works. and the other gauges work also. except the gas gauge. The car is a 1960 model if that helps.
 
DARTLARRY said:
I am working on an old chrysler. And the fuel gauge reads full all the time, as if it were grounded. I have checked all the wiring, and it seems fine. what else could I be missing? The gauge obiviously works. and the other gauges work also. except the gas gauge. The car is a 1960 model if that helps.
Click to expand...

You need to verify the wiring from the sending unit to the gauge is actually good with a multi meter - make sure there's no excessive voltage drop or unwanted resistance that would cause an inaccurate reading. Check it at various points to find the problem. Just cause it 'looks' OK does not mean it is.

Also, if it's doable, you might need to look into checking the ohm sweep on your sending unit. There's an arm on the unit that's attached to a float in the tank. It creates a certain amount of resistance when the fuel is at a specified level. If the wiring checks out OK, I'd look there.
 
If the gauge needle moves from home position to full at switch on, and continues to operate in just that manner for any length of time,
the fault has to be the sender. If the sender wire was grounded to zero resistance the gauge would die in 5 minutes or less.
Once inside the sender I expect you'll find what was a round contact point simiilar to a BB shot is worn away to 2 hook like points and snagged on the resistor wire.
Prove me wrong, wont hurt my feelings :)
Good luck
 
That sounds like the problem. I will pull the tank and try to prove you wrong. But I doubt that I will. Thanks.
 
Another question. Is there a way to test the sending unit out of the car. Maybe ground it and watch the gauge as the arm moves up and down. I dont know.
 
DARTLARRY said:
Another question. Is there a way to test the sending unit out of the car. Maybe ground it and watch the gauge as the arm moves up and down. I dont know.
Click to expand...
You can test the sender with an ohm meter. One lead on the contact post, other lead to ground. Much simpler than having a known good gauge and 5 volt power supply on the workbench.
 
I meant, with the sending unit out of the tank. Can i hook the wire to the unit, ground it and move the arm, then watch the gauge in the car.
 
No you can't crawl under there and play with the darn thing Sparky.
I try to be polite but it aint easy. sheesh
 
I dont think that you understand what I am asking. I am not crawling under anything. The sending unit will noe be in the tank. The tank will not be in the car.
 
Yep, did that with mine, just make sure the ground is good.
 
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