69 Chrysler 300 Gas Gauge

MJFUR

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Need some help trouble shooting the gas gauge, 69 Chrysler 300. Not sure if the gauge ever worked, bought the car (needle was on or near Empty), drove it around the block twice and tore the car apart.

Fast forward a couple of months, new fuel tank, new fuel sending unit, new fuel lines. I have about 3 or 4 gallons in the tank now, gauge shows Empty.
I have continuity from the gas tank to the tank straps, from the gas tank to the fuel line, from the Sending Unit post to the gas tank, fuel line, tank straps, etc.. I seem to have continuity all over the place.
I do not have continuity from the gas tank to the rear sub-frame, which is odd since I do have continuity to the fuel line that is attached/clipped to the sub-frame.

I do not have continuity from the Sending Unit wire to anything that I tried, tank, straps, Sending Unit post, sub-frame, etc.

Thx

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Big_John

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The fuel line strap often not optimum for grounding the sender body. While it attaches to the line that is clipped to the body, things like rust and undercoating tend to make for a bad ground.

I soldered a male connector on mine and ran a wire to the frame.

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1970FuryConv

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Need some help trouble shooting the gas gauge, 69 Chrysler 300. Not sure if the gauge ever worked, bought the car (needle was on or near Empty), drove it around the block twice and tore the car apart.

Fast forward a couple of months, new fuel tank, new fuel sending unit, new fuel lines. I have about 3 or 4 gallons in the tank now, gauge shows Empty.
I have continuity from the gas tank to the tank straps, from the gas tank to the fuel line, from the Sending Unit post to the gas tank, fuel line, tank straps, etc.. I seem to have continuity all over the place.
I do not have continuity from the gas tank to the rear sub-frame, which is odd since I do have continuity to the fuel line that is attached/clipped to the sub-frame.

I do not have continuity from the Sending Unit wire to anything that I tried, tank, straps, Sending Unit post, sub-frame, etc.

Thx

View attachment 524696
I recommend you attach alligator clips to the ends of a long wire, then attach one alligator clip to the sending unit wire connector. Attach the other at battery negative post. Then make sure the dash gas gauge needle goes all the way to full.
If not, you may have resistance in the sending unit wire or problems with the gauge itself or lack of input power to the gauge.
 

thethee

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Sorry if this is too obvious, you say you checked for continuity, but have you checked the sending wire for voltage?
 

MJFUR

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Yes, I have a pulsating voltage on the sending wire. I can go from the wire to ground and get voltage. I can go from the wire to the Sending Unit post and get voltage.
Looks like the gauge is inop.

Can I repair at home or does the gauge panel need sent out? If so, where?

Thx
 
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