# Fuel sending unit/fuel gauge issue



## xconcepts (Jan 4, 2009)

Ok so a few months ago I replaced my fuel sending unit in the tank since it hasn't been changed in probably 10+ years. The sock was black....however my fuel gauge read correctly. After I changed it to the new unit from autozone it hasn't read correctly. It never got near 1/2 tank even if I filled it. 

So I thought maybe the sender is bad and dropped the tank yesterday. I didn't have anyone with me so I ran a wire from the ground and from the acc underneath the car and sat in the drivers seat with the sender in my hand. I messed with the fuel lever and it only got to 3/8's. So I got autozone to warranty it out for a new unit. SAME THING....3/8's with the lever all the way up. 

WHY???? Is my ground bad? The Acc? It originally had the plug in for acc for the old sender. The new one was a screw in so I cut the wire and added a ring terminal. Its secure.


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## 05GTO (Oct 6, 2004)

The 64 GTO used fuel sending units with a range of 0-30 ohms, 1965-72 is 0-90 OHMS.

Use an ohm meter and check the original sending unit with the lever in both the empty and full condition and compare those resistor values with your new sending unit. You may have a 64 sending unit which would explain why the needle only goes to 3/8ths.

The wire you are calling Acc is also a ground that feeds the negative side of the fuel gauge, the sending unit works like a variable resistor, I.E. 45 ohms should show 1/2 tank.


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## xconcepts (Jan 4, 2009)

I don't have the old sender anymore, but u just checked to ohms and it reads 0-35. So I have the right one


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## 05GTO (Oct 6, 2004)

xconcepts said:


> I don't have the old sender anymore, but u just checked to ohms and it reads 0-35. So I have the right one


I edited my above post, you should be reading 0-90 ohms, the information I posted to begin with was not correct.


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## Eric Animal (Oct 28, 2007)

:agree with Randy 0-90 OHMS...if you can't get a properly working sender....I would reccomend a Robb Mc unit...they sell a quality product with great service (also starters, fuel pumps). I see no reason why you can't get a proper unit from autozone. Personally, I like to patronize the 'specialty guys' Like OPGI, Performance Years,Ames, etc....IMHO. Eric


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