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1970 road runner Fuel Gauge issues

Lucky Lar

Lucky Lar

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Can’t get fuel gauge to read full when the tank is full of gas

I have 2 sending units, one brand new the other looks original, when I hook them up out of the tank the sending units & the gauge in the car work perfect

But when I put them back in the tank they will only go to a little under ¾ when the tank is full

Has anybody had the same issue, and is there a fix

Thanks larry
 
You'll have to bend the arm a little one way or the other to get it to read where you want...a big hassle I know...mine read 1/2 with a full tank. I got it to read better but still not perfect, just haven't wanted to pull the tank down again....
 
beanhead said:
You'll have to bend the arm a little one way or the other to get it to read where you want...a big hassle I know...mine read 1/2 with a full tank. I got it to read better but still not perfect, just haven't wanted to pull the tank down again....
Click to expand...
thanks will try it
 
Also check the float. Sometimes they develop small holes because of the chemical additives in Gasoline. The floats gradually fill up and they become less buoyant causing the gauge to read inaccurately...cr8crshr/Tuck:thumbsup::thumbsup::thumbsup::usflag::usflag::usflag:
 
Don't know many who have not had this. Mine read 3/4 when full of years. You can bend it, but mine was a ground issue. Goes to full now.
 
Mine was reading 3/4 full, then one day I topped the tank to the max and ever since then it reads full when full (but now it shows empty when it has 4-5 gallons).
 
Agree with Dennis good solid ground is a must! I ran my own didn't trust that cheesy OEM clip
 
Dibbons said:
Mine was reading 3/4 full, then one day I topped the tank to the max and ever since then it reads full when full (but now it shows empty when it has 4-5 gallons).
Click to expand...

Same here empty with 4/5 gallons left. Different reason, in 1978 when I bought my car gas gauge didn't work. Pulled tank and resistor wire broken on empty end. No replacement, so remove 1 turn and resoldered it. So is empty is 1/4 full.
 
Last edited:
Mine has always read 3/4 when full. I don't worry about it. When it hits E, I fill it up again. Easy.
 
Finally was able to get the fuel gauge to read full with a full tank
Installed Bill Rolik sending unit, i could see that the neck on the BR unit sits lower in the tank than the one I pulled out & the first after market unit i bought
the other 2 units floats would hit the top of the tank in the 3/4 position
 
Lucky Lar said:
Finally was able to get the fuel gauge to read full with a full tank
Installed Bill Rolik sending unit, i could see that the neck on the BR unit sits lower in the tank than the one I pulled out & the first after market unit i bought
the other 2 units floats would hit the top of the tank in the 3/4 position
Click to expand...

Do you have a link or picture of his sending unit and contact info? Does he rebuild old ones?
 
8EDFC511-58FD-4230-9068-2DBF53E7A910.jpeg
Oh the feeling of seeing this after 30 years...
 
Ground issue per shop tech. It’s a mega $$$ custom tank from Ricks Tanks in El Paso to accommodate the new efi. It was fixed before that though.
 
Lucky Lar said:
Can’t get fuel gauge to read full when the tank is full of gas
Click to expand...
I'll bet it hangs on 3/4 full for a lot longer than it should.....try bending the arm like others have suggested above.
I had a replacement sender that needed adjustment...doesn't take much to sort that out.

If you have a sender with a grub screw holding the float arm...try adjusting the position, and if needed, also bend the arm - the arm could be too long once bent upwards more.
 
kiwigtx said:
I'll bet it hangs on 3/4 full for a lot longer than it should.....try bending the arm like others have suggested above.
I had a replacement sender that needed adjustment...doesn't take much to sort that out.

If you have a sender with a grub screw holding the float arm...try adjusting the position, and if needed, also bend the arm - the arm could be too long once bent upwards more.
Click to expand...
Thanks for the info I will give a try
 
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