NOS sending unit doesn't work

[kiss]

A few months ago I broke down and bought a NOS sending unit off ebay for my 71 Dart. I was using a Spectra aftermarket one that had all kinds of problems (linear so gauge read wrong, pickup tube not deep enough in the tank, etc). Unfortunately the NOS sending unit doesn't work. I imagine the ohm readings are off. When I turn the car on the needle raises to E and that's it.

Yes I checked the grounding strap (its new) and I have 1 of the aftermarket solid state voltage limiters on the back of the instrument cluster.

My question is, is there any way to rebuild the stock sending unit? rewind it somehow? Is there a place I can send it to which does this? Or should I try and get my money back from the ebay seller.

Oh also, no, the float is fine it doesn't leak.

 

[justinp61]

Did you ohm it before installing?

 

[68gtxman]

A few months ago I broke down and bought a NOS sending unit off ebay for my 71 Dart. I was using a Spectra aftermarket one that had all kinds of problems (linear so gauge read wrong, pickup tube not deep enough in the tank, etc). Unfortunately the NOS sending unit doesn't work. I imagine the ohm readings are off. When I turn the car on the needle raises to E and that's it.

Yes I checked the grounding strap (its new) and I have 1 of the aftermarket solid state voltage limiters on the back of the instrument cluster.

My question is, is there any way to rebuild the stock sending unit? rewind it somehow? Is there a place I can send it to which does this? Or should I try and get my money back from the ebay seller.

Oh also, no, the float is fine it doesn't leak.

Use the linear sender and buy a meter match unit to calibrate it. TechnoVersions - MeterMatch for Analog Gauge Correction

 

[kiss]

Did you ohm it before installing?

Nope, didn't have the meter with me. Installed it, didn't work, a week later at a family member's place I removed it and checked the ohm.

Use the linear sender and buy a meter match unit to calibrate it.

Which is a good linear unit? There's a few to choose from and I don't know which. The one I had was crap, the pickup tube didn't even reach the bottom of the tank, and it was so flimsy I was scared to bend anything.

 

[68gtxman]

Which is a good linear unit? There's a few to choose from and I don't know which. The one I had was crap, the pickup tube didn't even reach the bottom of the tank, and it was so flimsy I was scared to bend anything.

I bought one from Rock Auto. Good price and nice unit. $55 for 5/16" and $60 for 3/8" For 1967 Barracuda 273. Select the one for your specific application though. More Information for DORMAN 692152

 

[mvh]

There is no way to calibrate a "linear" unit to read accurately on an A-body tank. Because of the spare tire well in the top, the original sender is wound non-linearly, in order to correctly indicate a half-tank. A linear sender could potentially be calibrated to be correct at E and F, but it would be way off at 1/2 (it would read on the 1/2 mark with something like 3/4 tank remaining). You can decide if that is good enough, I suppose.

 

[kiss]

There is no way to calibrate a "linear" unit to read accurately on an A-body tank. Because of the spare tire well in the top, the original sender is wound non-linearly, in order to correctly indicate a half-tank. A linear sender could potentially be calibrated to be correct at E and F, but it would be way off at 1/2 (it would read on the 1/2 mark with something like 3/4 tank remaining). You can decide if that is good enough, I suppose.

Do you know if I can rebuild the NOS sending unit?

 

[harrisonm]

Over the years, I have had about 50% luck with 40 - 50 year old NOS electrical parts. Don't know if electrical stuff goes bad sitting on the shelf, but that's the way it's been for me.

 

[68gtxman]

There is no way to calibrate a "linear" unit to read accurately on an A-body tank. Because of the spare tire well in the top, the original sender is wound non-linearly, in order to correctly indicate a half-tank. A linear sender could potentially be calibrated to be correct at E and F, but it would be way off at 1/2 (it would read on the 1/2 mark with something like 3/4 tank remaining). You can decide if that is good enough, I suppose.

Don't condemn any product without knowing what it can do beforehand my friend. See the screen capture above and you'll see that MeterMatch has two additional set points that can be used to make adjustments for non-uniform tank profiles.

 

[Dartnut]

Hmmm.
My Spectra sending unit has worked perfectly since day one and is still as good today as when i installed it, and that's over 3 years now.
On another note, you installed the N.O.S. one and used it for a week and aren't satisfied with it, AND want the seller to take it back and give you a refund........
Good luck with that.
I know if i were the seller, i would tell you no way. (for lack of a better way of saying it)

 

[RedFish]

The tank shape is not the only non linear player. OEM fuel gauge operation...
80 ohms = no needle movement
73 ohms = empty hash mark
23 ohms = half hash mark
10 ohms = full hash mark
A linear instrument operating from 80 to 10 would have half at 35.
Always amazes me that so many are unwilling to believe the gauge is the fault.
Inside the gauge is a resistor wire wound in a bi metal beam. The winding gets hot, the beam bows.
So the gauge is very much the same as the mechanical limiter in how it works.
So what makes the fuel gauge different from the other thermal gauges ? Why do fuel gauges die so much more often than temp' gauges ? Simple answer is, "a full tank". A temp gauge never sees the high end / lesser ohms / higher heat. A fuel gauge not only sees the higher temp but also sees many many rapid temperature swings that a temp' gauge never see. Also keep in mind that if/when a mechanical limiter sticks closed and sends far too much voltage through the thermal gauges, the fuel gauge will suffer the brunt of it due to the fuel level. ( yeah this read is t.m.i. )
Can something like the meter match unit get a couple more years of "close to right" operation from a cooked gauge ? Yes. Can some of the solid state regulators also extend the life of a cooked gauge? Yes. Will anything patch over cooked ? No
As for this members "NOS sender" not functioning properly, 2 possibilities... Either you were scammed ( its not what it was advertised to be ), or this sender has been defective since day one. I say that because I have 3 rallye fuel gauges here that are seconds, Factory defects that should have never left the factory. Each has a different fault too. Two of these never worked as they should. The third did work until its factory defect lead to early death.
In closing, I'll submit that a good NOS a-body sender would have been installed and in use about 20 years ago.
p.s. 3 factory defects found are of the 534 across my table