Yup, another fuel gage question......

[Bill Monk]

Not to jack this thread but the gauge on my ‘69 RR shows way past full. Gauge comes up when you turn the key on and down when the key is off. It seems to just read excessively high. They gent who I bought the car from has said that it works just goes way out passed full when the tank is full. Says it’s close to empty at between 3/4 and full. Any of you have this problem?

Mine reads 3/4 full with a full tank so I still have 1/4 tank when it hits empty. I know it's the sender but don't feel like pulling it back out so I just live with it

 

[65-440]

Mine reads 3/4 full with a full tank so I still have 1/4 tank when it hits empty. I know it's the sender but don't feel like pulling it back out so I just live with it

Exactly how mine is ..

 

[PeteBell68]

Same , just think of it as a 4 1/2 gallon reserve ..

 

[koosh]

Okay good, now make sure you have a zero ohm ground path from the tanks SENDER HOUSING to the frame. There's a bonding "clip" about 6" long that should go from the sender fuel outlet to the fuel line (to cross the rubber joint). Sender gets it's ground from the fuel line being clamped to the frame. Quick check use that same ground point you just used and jumper to the SENDER face plate... see if your gauge now shows 1/2 tank or what ever fuel you have in it.
View attachment 606330

 

[koosh]

Okay good, now make sure you have a zero ohm ground path from the tanks SENDER HOUSING to the frame. There's a bonding "clip" about 6" long that should go from the sender fuel outlet to the fuel line (to cross the rubber joint). Sender gets it's ground from the fuel line being clamped to the frame. Quick check use that same ground point you just used and jumper to the SENDER face plate... see if your gauge now shows 1/2 tank or what ever fuel you have in it.
View attachment 606330

ok.....there was NO bonding clip at all...so i grabbed piece of baling wire, wrapped it around the outlet, then clamped other end to fuel line...turned key on, needle barely moved up to empty.....then i unhooked then end that i clamped onto the fuel line and clipped it to the new ground spot on tbe rear frame that i used previuosly, no change!

 

[miller]

Something to look for? I'll only guess the same is on the later cars.

On my 64, the old fuel line was a tangled, rusted mess. Held onto it, for a guide, when I installed new line. On the old line, was a bare metal clamp, near the rear. Okay. Made my own new fuel line, and where that clamp was located, from the sending unit, line goes straight up, along the front of the trunk. Then a bend, to the right-side wheel well. Right where that bend is, a screw hole, where that clamp goes.
Pretty sure, the bare clamp, screwed to the body, makes solid ground for the fuel line.

Not saying that's the only problem...but, my gauge works!

 

[koosh]

Something to look for? I'll only guess the same is on the later cars.

On my 64, the old fuel line was a tangled, rusted mess. Held onto it, for a guide, when I installed new line. On the old line, was a bare metal clamp, near the rear. Okay. Made my own new fuel line, and where that clamp was located, from the sending unit, line goes straight up, along the front of the trunk. Then a bend, to the right-side wheel well. Right where that bend is, a screw hole, where that clamp goes.
Pretty sure, the bare clamp, screwed to the body, makes solid ground for the fuel line.

Not saying that's the only problem...but, my gauge works!

I am connected to a fresh body ground now, with no results. But thanks

 

[dadsbee]

Get a strong light and shine it in the tank neck. See if your float is sunk. If not at this point I'd say your rheostat is toast, but I question even that as if it was "open" the gauge probably wouldn't come up to empty.. so I suspect float sunk.

 

[bearman]

You stop it with the fuel gauge thing just stop at every corner and fill up. Just kidding I found on a couple that the rod for the float needed adjustment then it worked fine. Got to love the cheesie rhoestat also good parts hard to fiind

 

[koosh]

Get a strong light and shine it in the tank neck. See if your float is sunk. If not at this point I'd say your rheostat is toast, but I question even that as if it was "open" the gauge probably wouldn't come up to empty.. so I suspect float sunk.

View attachment 606880

Cant see inside the tank.....but i did grab tge ohm meter....checked sender face plate to good ground--zero'd out....checked sender terminal to good ground----zero'd out......checked sender face plate to sender terminal---zero'd out......i need a scotch.....

 

[dadsbee]

LOL... ~10 ohms full, ~70 ohms empty. Sounds like she's toast..

 

[koosh]

LOL... ~10 ohms full, ~70 ohms empty. Sounds like she's toast..

What setting should i have used? Im not sure what the hell im doing with a meter!
What is the starting point?

 

[dadsbee]

Not sure what you have, I have them all but for this stuff I use my digital. Not sure what range scales you have, but like I said the full sweep of the fuel sender rheostat and oil pressure (with gauge) and engine Temp senders are all approximately 10 Ohms Full gauge scale and 70 ohms empty.. zero.. cold.

When you were getting "zero'd out", did you at least have the meter on Ohms?.. and not DC power or some other setting?

 

[koosh]

Not sure what you have, I have them all but for this stuff I use my digital. Not sure what range scales you have, but like I said the full sweep of the fuel sender rheostat and oil pressure (with gauge) and engine Temp senders are all approximately 10 Ohms Full gauge scale and 70 ohms empty.. zero.. cold.

When you were getting "zero'd out", did you at least have the meter on Ohms?.. and not DC power or some other setting?

I set it to 2ohms....by zerod out, i mean when touching both leads it reads zero
I assume it means "continuity"

 

[dadsbee]

Okay fine.. so your meter is zero'd. If you had it on a 2000 ohm scale or similar it's going to be so close to zero you won't see it. You need the meter on a 100 ohm scale if it has one.

You sure you can't see in the tank with a strong pin point style mag light? Don't use a match unless you really want to! LOL

 

[koosh]

Okay fine.. so your meter is zero'd. If you had it on a 2000 ohm scale or similar it's going to be so close to zero you won't see it. You need the meter on a 100 ohm scale if it has one.

You sure you can't see in the tank with a strong pin point style mag light? Don't use a match unless you really want to! LOL

 

[koosh]

I tried tne meter on a number of settings with all same results...i will see about getting a flashlight small enough to enter the fuel fill neck

 

[miller]

I tried tne meter on a number of settings with all same results...

To be able to check the sending unit, ohm meter needs to be set for the 0-100 range. Play with the meter, until you figure it out.
On those meters, just about for each different 'range', the ohms needs to be re-set to 0, with the two leads touching.
Until you get that right, your just wasting your time with the meter.

Going from ground, to the sending unit gauge wire post, you should get a reading somewhere between 10 and 73, depending on how much gas is in the tank.

 

[koosh]

Get a strong light and shine it in the tank neck. See if your float is sunk. If not at this point I'd say your rheostat is toast, but I question even that as if it was "open" the gauge probably wouldn't come up to empty.. so I suspect float sunk.

View attachment 606880

Ok....found light small enough to get inside neck...still see nothing, everything must b sunk!

 

[koosh]

To be able to check the sending unit, ohm meter needs to be set for the 0-100 range. Play with the meter, until you figure it out.
On those meters, just about for each different 'range', the ohms needs to be re-set to 0, with the two leads touching.
Until you get that right, your just wasting your time with the meter.

Going from ground, to the sending unit gauge wire post, you should get a reading somewhere between 10 and 73, depending on how much gas is in the tank.

Set my old fashion Simpson meter on R100....one lead on good ground, other on sender terminal----- 0 ohms!
(Keep in mind original sender wire still attached)