Gas gauge not working

[turboplow]

My car sat for six years so I dropped the tank cleaned it, replaced hoses and clamps and the
gas gauge needle is buried on the full side. If someone could tell me how to get it to work again it
would be much appreciated. Thanks for any input.

 

[regan j]

With limited info, I would say you do not have a good connection somewhere. Gauge shows way past full when bad connection.

 

[Nick Micale]

With limited info, I would say you do not have a good connection somewhere. Gauge shows way past full when bad connection.

You are correct, the bad connection almost always in the tank, especially if it is the original 25+ year old POS sending unit.

Before I replace any fuel pump with an original sender, the customer is informed that if the gauge does not work after it is installed, I will not be responsible for that?

It is very easy to check the sender before it is installed by plugging it into the factory connector, and watch the fuel gauge while someone moves the float lever.

Yesterday I had a customer handle an original sender I was going to install, when he gave it back to me the plastic tab on the float was broken, so it went into the trash instead of the car.

I will have a new sender here in 2 days from Amazon for under $100, the cost to R&R the tank again!

 

[turboplow]

thanks for the info. Doesn't sound too bad to fix.

 

[TireFryer]

You are correct, the bad connection almost always in the tank, especially if it is the original 25+ year old POS sending unit.

Before I replace any fuel pump with an original sender, the customer is informed that if the gauge does not work after it is installed, I will not be responsible for that?

It is very easy to check the sender before it is installed by plugging it into the factory connector, and watch the fuel gauge while someone moves the float lever.

Yesterday I had a customer handle an original sender I was going to install, when he gave it back to me the plastic tab on the float was broken, so it went into the trash instead of the car.

I will have a new sender here in 2 days from Amazon for under $100, the cost to R&R the tank again!

I tried this with a known good sender, which I tested with multimeter... Plugged it into the hotwire kit = turn key to on (not start), fuel pump ran for 2secs but gauge still buried past fuel, even when moving fuel level from empty to full. Plugged sender into the factory plug = same result.
What should I look at next? Hot wire fuse is good at alternator, ground screw cleaned and reattached to frame... No change. When I put multimeter across the middle and end wire of the fuel sender 3 wire plug, I got a reading of 60 (my bench test spare sender had range from 3 (empty) to 98 (full).

 

[TexasT]

I'd drop the tank down pull that sender out and do some more "testin" on it. With the sender plugged in and the key on the gauge should move when you move the float. As pointed out by nick these pieces are old and brittle and have been submersed in who knows what quality of gasoline and tank fumes for a LONG time. The resistor setup on the hanger can become bent when maneuvering the float into the tank affecting its ability to send the signal. you may have to "massage" the resistor slider to get it to work. But be gentle as it is old and things tend to go sideways in a hurry.

Old stuff is real fun to work on. Sometimes you get to do things multiple times to get it to function correctly.

 

[TexasT]

And if they go sideways. A replacement is always a good idea if you want the gauge to work.

Fuel Pump Hanger - OEM Replacement, HFP-HR7680 QFS

QFS Offers OEM Replacement Fuel Pump Hanger. Boasting Drop-in replacement, Free Shipping, Easy Installation, with our HFP-HR7680.

www.highflowfuel.com

 

[TireFryer]

In hunting down the issue with the multimeter, we figured that the issue was at the dash/gauge. Took out the cluster and this is what was found behind it! 2 bent pins!!!
Well, we straightened out the pins carefully, reinstalled the cluster and VIOLA, we got fuel gauge working as well as a couple of items which were kinda funky cleared up since the top squished pin was a ground pin and was not making a good contact.
Thanks to all who provided advice and guidance.