Re: '39 tank/sender/gauge
Posted by HH56 On 2016/11/23 21:31:12
Does the car have an OD. If so, does the engine suddenly die when given gas. If you do have OD check that the ign cutout part of the kickdown circuit is OK and the switch is not grounding the coil prematurely. If it seems like it is running out of gas and you have a old rubber hose between the steel fuel line and the pump make sure the hose is good and not damaged or restricting fuel flow when the engine is calling for more. Collapsing under suction and the lining cracking and a piece moving and blocking flow are common in old hoses.
Not sure what kind of setup you have at the sender to have two wires. A stock sender would have a single terminal for a wire to the gauge and the ground would be provided by the tank metal grounding to the body and frame. If you have two wires I would expect one of the wires should be grounded but you will need to verify what you have.
Packard used a couple of manufacturers of gauges in 39 and I don't know the resistance range of either sender. I suspect it will be around 100 ohms empty and 0 full but will not swear to that. The gas gauge has two electromagnets which each pull against the needle. When in operation the sender causes the magnetic strength of one of the electromagnets to vary. When the sender resistance is high the magnet connected directly to the sender is weaker so the stronger one pulls the needle one direction. When resistance is low the connected magnet is stronger and pulls the needle the other direction. A half full tank and the magnets are balanced so the needle is in the middle.
In that type circuit the dash gauge as well as the sender needs to be grounded so verify that is the case.
Here is a photo from KM Lifestyle showing a typical sender that would be in the car. You might compare yours and see how much if any differences there might be. If you do need a sender and one of our vendors can't help, KM says they have some NOS and can also make brand new ones if needed.
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Not sure what kind of setup you have at the sender to have two wires. A stock sender would have a single terminal for a wire to the gauge and the ground would be provided by the tank metal grounding to the body and frame. If you have two wires I would expect one of the wires should be grounded but you will need to verify what you have.
Packard used a couple of manufacturers of gauges in 39 and I don't know the resistance range of either sender. I suspect it will be around 100 ohms empty and 0 full but will not swear to that. The gas gauge has two electromagnets which each pull against the needle. When in operation the sender causes the magnetic strength of one of the electromagnets to vary. When the sender resistance is high the magnet connected directly to the sender is weaker so the stronger one pulls the needle one direction. When resistance is low the connected magnet is stronger and pulls the needle the other direction. A half full tank and the magnets are balanced so the needle is in the middle.
In that type circuit the dash gauge as well as the sender needs to be grounded so verify that is the case.
Here is a photo from KM Lifestyle showing a typical sender that would be in the car. You might compare yours and see how much if any differences there might be. If you do need a sender and one of our vendors can't help, KM says they have some NOS and can also make brand new ones if needed.
Attach file:
(47.09 KB)
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