Fuel gauge only goes to half

[SMack]

Thanks for all the input guys. Great info. Now that my tank is full again I’m going to sit tight until spring and start again.
I think the assembly or float arm needs some bending. This time though when the tank is in the ground I’m going to run a jumper wire from the hot and ground under the car to the tank so I can play with it and se how my gauge acts as well.

Merry Christmas

 

[Suregrip391]

It Seems like this should be a simple part to make and work correctly. Yet it has been YEARS of people buying junk aftermarket senders that don’t work right out of the box. Manufacturers have no interest in fixing these, why?.. because we are buying them anyway? It’s maddening.

 

[bee71]

Thanks for all the input guys. Great info. Now that my tank is full again I’m going to sit tight until spring and start again.
I think the assembly or float arm needs some bending. This time though when the tank is in the ground I’m going to run a jumper wire from the hot and ground under the car to the tank so I can play with it and se how my gauge acts as well.

Merry Christmas

Remember that having the tank sitting on the ground is a different pitch than when it is on the car.

 

[dadsbee]

Remember also that there is no "HOT" to the tank or sender. That is a variable ground wire to the gauge via the sender rheostat and the tank sending unit needs to be grounded. Gauge gets it's "HOT" from the 5 volt regulator.. not 12v. Just take the sender wire off the sender and ground it to the frame and have someone watch the gauge. Does it go full scale?? Ground it again to the tank sender face itself, does it go full scale?? If it does in both cases, the sending unit is at fault. If it doesn't go full scale it is your gauge. Doesn't go full scale grounded to the tank senders face then you also have an issue with the tank sender not being grounded properly.

 

[miller]

If it doesn't go full scale it is your gauge.

Maybe.
Besides the sending unit being bad, though possibly repairable, the whole circuit needs to be checked. Gauge itself can be tested, by itself. Grounding the one side, should slowly move full sweep.
From front to rear, the 'hot' sending wire needs to be ohm tested. If the wire is bad...replace it!

On my 64, after testing both the gauge, and wire, both were good. Gas tank is new. Had bought one of the aftermarket sending units, compared it to the couple old units I had, easy to tell the aftermarket was junk. Just on the rheostat windings, only a third compared to the stock units. Back in the box!
I 'repaired' one of the stock units, using parts off two, and got a good one. Gauge reads full, when tank is full.

Last note, on grounds, that I've mentioned before, is gas line ground. Tank isn't grounded, sending unit is! Remember, there's a rubber seal, between the tank, and sending unit. Metal grounding strap, the spans across the gas line to sending unit, over the connecting rubber hose, connects that.
But, straight above the sending unit, how the gas line fits to the frame/body, there is a steel tubing clamp, that holds the line in place, and also makes positive ground for the gas line.

 

[dadsbee]

I meant tank "sender" needs to be grounded and I edited my text to say so. As for the gauge, just didn't want him looking at the wrong end for the issue.

 

[SMack]

Great point about the pitch bee71 thanks. Great info from all you guys and i appreciate the wealth of knowledge and willingness to help

Many thanks

 

[Don Frelier]

My 66 Satellite would work on and off with a new mopar sending unit. I loosened, then tightened the nuts on the back of the gauge.
Works fine now.

 

[mac]

maybe an option. read the whole thing for what you need for mopar.

https://www.technoversions.com/MeterMatchHome.html?

 

[inverse1216]

for what its worth I just got one from classic industries and it seems to be within the required range.

 

[dadsbee]

It is not the "range" that truly matters, it's where in the sweep you have what resistance. The OE rheostats are not "linear" but all the reproductions are, hense they don't give correct readings between E and F . Here's a tracing I did off my '70 Birds OE sender float arm if you want to check for correctness.

 

[beanhead]

Yeah..maybe that's why the manufacturers haven't changed. They will show the proper ohm range, as shown above,(mine did too!) but they still almost always need adjusting(bending) to put the gauge needle in the right spot at the right time(mine did too!).

 

[inverse1216]

It is not the "range" that truly matters, it's where in the sweep you have what resistance. The OE rheostats are not "linear" but all the reproductions are, hense they don't give correct readings between E and F . Here's a tracing I did off my '70 Birds OE sender float arm if you want to check for correctness.View attachment 823993

good to know! ill pull mine back out since I haven't installed the tank yet due to some incorrectly stamped fuel tank straps and compare it to your diagram.

 

[coronet68mx]

I finally found an original one for the X and sent it out and got it restored. When the car gets back from the museum. I will see it this the cure.....

IF you get it back...

 

[moparnation74]

IF you get it back...

Counting the days.......I already have an itinerary laid out for the X next year

Might even make a Latin guy

 

[coronet68mx]

Counting the days.......I already have an itinerary laid out for the X next year

Might even make a Latin guy

Btw, your inbox is full.

 

[PeteBell68]

You would honestly think someone would make a correct working non crap sender .
I've emailed Tony and a few other suppliers and said if it worked you'd sell thousands and if it was a guaranteed fix I'd even prepay to help tool it .Tough to even find a rebuild able core .
As it stands I fill up at E and have a 5-7 gallon reserve .