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Discussion Starter #1
fuel / gas tank sender / sensor float replacement info
I just replaced the the sensor in the tank of my 1966 GTV. It has the Veglia gauges and uses the corresponding sensor. I put in a new sensor from Centerline (approx $50). The new sensor's cap looks the same, but the internals are slightly different. Looks to me the same functionality and shape, just made by a different manufacturer, almost certainly modern given the zip tie on the inlet filter.
At any rate, I took some measurements that may be useful for someone else testing their sensor. These measurements were the same on the new sensor and the old one.

Resistance from the T terminal to ground:
91 Ohms with the float up (full tank)
9 Ohms with the float down (empty tank)
(as you move the float the resistance changes between these measurments, this is how the gauge determines the fuel level)

Resistance from the W terminal to ground:
infinite Ohms with the float up (full tank)
0.5 Ohm with the float down (empty tank)
(the resistance stays infinite until the tank is nearly empty and then jups directly to 0.5 Ohm: this is for the low fuel warning light)

Incidentally, if anyone wants my old sensor let me know... it appears to be original. The problem was the float has a small hole in it and had filled with fuel. If you can glue the hole closed, this sensor would probably work fine. I cleaned the contacts and the resistance measurements seemed the same as the new sender. But I do note the pivot is worn and it might not be completely reliable. Certainly it is rebuildable by someone who likes doing that kind of thing. At any rate, pay me for the shipping and it's yours. Just send me a PM.
Pics below:
 

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fuel / gas tank sender / sensor float replacement info
I just replaced the the sensor in the tank of my 1966 GTV. It has the Veglia gauges and uses the corresponding sensor. I put in a new sensor from Centerline (approx $50). The new sensor's cap looks the same, but the internals are slightly different. Looks to me the same functionality and shape, just made by a different manufacturer, almost certainly modern given the zip tie on the inlet filter.
At any rate, I took some measurements that may be useful for someone else testing their sensor. These measurements were the same on the new sensor and the old one.

Resistance from the T terminal to ground:
91 Ohms with the float up (full tank)
9 Ohms with the float down (empty tank)
(as you move the float the resistance changes between these measurments, this is how the gauge determines the fuel level)

Resistance from the W terminal to ground:
infinite Ohms with the float up (full tank)
0.5 Ohm with the float down (empty tank)
(the resistance stays infinite until the tank is nearly empty and then jups directly to 0.5 Ohm: this is for the low fuel warning light)

Incidentally, if anyone wants my old sensor let me know... it appears to be original. The problem was the float has a small hole in it and had filled with fuel. If you can glue the hole closed, this sensor would probably work fine. I cleaned the contacts and the resistance measurements seemed the same as the new sender. But I do note the pivot is worn and it might not be completely reliable. Certainly it is rebuildable by someone who likes doing that kind of thing. At any rate, pay me for the shipping and it's yours. Just send me a PM.
Pics below:
fuel / gas tank sender / sensor float replacement info
I just replaced the the sensor in the tank of my 1966 GTV. It has the Veglia gauges and uses the corresponding sensor. I put in a new sensor from Centerline (approx $50). The new sensor's cap looks the same, but the internals are slightly different. Looks to me the same functionality and shape, just made by a different manufacturer, almost certainly modern given the zip tie on the inlet filter.
At any rate, I took some measurements that may be useful for someone else testing their sensor. These measurements were the same on the new sensor and the old one.

Resistance from the T terminal to ground:
91 Ohms with the float up (full tank)
9 Ohms with the float down (empty tank)
(as you move the float the resistance changes between these measurments, this is how the gauge determines the fuel level)

Resistance from the W terminal to ground:
infinite Ohms with the float up (full tank)
0.5 Ohm with the float down (empty tank)
(the resistance stays infinite until the tank is nearly empty and then jups directly to 0.5 Ohm: this is for the low fuel warning light)

Incidentally, if anyone wants my old sensor let me know... it appears to be original. The problem was the float has a small hole in it and had filled with fuel. If you can glue the hole closed, this sensor would probably work fine. I cleaned the contacts and the resistance measurements seemed the same as the new sender. But I do note the pivot is worn and it might not be completely reliable. Certainly it is rebuildable by someone who likes doing that kind of thing. At any rate, pay me for the shipping and it's yours. Just send me a PM.
Pics below:
Hi: Not sure if this is still a watched thread, but since the info is good and relevant I thought I'd try.

I'm trying to figure out if my sending unit is bad or not. But I'm not clear on how to test it. This is what I'm doing. Can you correct me please?

1. sending unit out of the tank
2. Multimeter set to check resistance
3. Red lead to sending unit terminal I'm measuring
4. Black lead to ???? (ground anywhere on the car?, the sending unit housing?, not sure)

Thanks in advance for the help.

Wayne
 

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Discussion Starter #3
Hi: Not sure if this is still a watched thread, but since the info is good and relevant I thought I'd try.

I'm trying to figure out if my sending unit is bad or not. But I'm not clear on how to test it. This is what I'm doing. Can you correct me please?

1. sending unit out of the tank
2. Multimeter set to check resistance
3. Red lead to sending unit terminal I'm measuring
4. Black lead to ???? (ground anywhere on the car?, the sending unit housing?, not sure)

Thanks in advance for the help.

Wayne
Completely remove the unit from the tank and disconnect all wires.
When measuring resistance on a device like this, the ohmeter leads are interchangeable, color does not matter.
For "ground" connect one of the leads to the metal top of the unit, where the attachment screws were.
Connect the other lead to the T or W terminal, for the tests I listed above.
 

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Completely remove the unit from the tank and disconnect all wires.
When measuring resistance on a device like this, the ohmeter leads are interchangeable, color does not matter.
For "ground" connect one of the leads to the metal top of the unit, where the attachment screws were.
Connect the other lead to the T or W terminal, for the tests I listed above.
Thanks for this info Vintageveloce. I have a bad sending unit and need to replace it.
 
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