51 plym Fuel Tank Sending Unit ?

[fadingfastsd]

Hey guys,

I've been reading all the threads on sending unit problems trying to troubleshoot my own problem. I also just ordered a shop manual off Ebay, so that should help when it gets here in a couple days.

When I picked up the car, my gauge didn't work correctly at all. When there was 1/4 tank or less gas, the gauge would flip intermittently from E to F on the gauge. When the tank was full, it sat right at E and did not move.

I had a spare gauge from another dash, so I replaced the gauge.

Now nothing works. I'm trying to figure out if this is a gauge or sending unit problem. If I ground out the single sending unit wire to the metal tank, the gauge doesn't move at all (should go to full with a short right?). So now I'm wondering if its the gauge that is not working. Does the gauge need to be powered?

Until I get the shop manual with the schematics, I'm not sure about the gauge. It had a post on the back, and a bullet connector. There were 2 ring terminals on the post, and a single wire plugged into the bullet connector.

Is one of these 6v, and the other the wire from the sending unit?

How can I troubleshoot the gauge?

Thanks guys,

Evan

[hucks 50]

check the wire in the trunk

[TodFitch]

Sounds like your original dash unit was at least reading something. If it were me I'd re-install it. Sounds like you may not have noted all the connections when you swapped in you other dash unit. You might have to get a manual to determine which post on the dash unit connects to which wire.

If I recall correctly your 51 should be a single wire unit. So I would expect one wire from the ignition switch and one wire to the tank sending unit. The manual will show the colors each wire should be and in some way indicate which connection on the dash unit each should go. However the wire coverings may have faded with time so you might have to manually trace the wires to see where they are going.

In my limited experience tank grounding and sending units are more likely to fail than the dash unit. Bob Amos (who posts on this board) did a nice write up on fitting an inexpensive universal sending unit into your vintage Plymouth. With his permission I have posted it at:

http://www.ply33.com/Repair/fuelsender.html