A friend has a 1959 dynamic 88 when we turn the key on the fuel gauge goes to full. We have checked the ground and it is good. Checkedvthe wire from where the plug plugs into the instrument circuit board and it checked out fine. Checked the sending unit with a multi meeter it read 0 at empty and 30 full. Im guessing unles I'm missing something here the gauge must be bad. Any advice here would be much appreciated. If it is the gauge where can I get a new gauge.

 

If you ground the wire that runs from the gauge to the sender does it move?

 

To be more explicit, if you ground the wire that you removed from the sender, does the gauge go to E?

 

Not sure i will try it tomorrow

 

Spoke to my friend he tried that and yes the gauge still whent to full

 

I had the same problem with my 59. I made an additional ground wire running from one of the bolts holding the sender to the tank to a hole I drilled in the frame. That fixed it.

 

A gauge that pegs on F when the wire from the gauge to the sending unit is disconnected from the sending unit and grounded with the ignition ON means an open circuit. Assuming the sending unit ground is good, you need to check the wire running from the dash gauge to the rear of the car for a break in the line.


I'm also a confused by this statement:

Checked it how? Just to make sure it's plugged in securely? If so, that's good, but you need to go further and verify the integrity of the entire circuit.

 

Mine would hover around over full then read somewhere on the gauge for a bit then go back to full. I was concerned it had something to do with the printed board on the solid state dash set up.
Before dismantling the dash I took it to an auto instrument place who could test the gauge, sender and wire. determined it to be the sender.
The fact the sender reads 0 - 30 is the normal ohm range, did you have it on the bench to test it?
Fusick ( and everyone else) only stock the non AC one so I made one out of the 2.
Works a treat

 

I tested the gray wire from the plug that plugs into the circuit board to where it connects to the sending unit and the wire is good

 

OK, this comment you made earlier:and this one you made just nowsuggests that the dash gauge is bad.

The definitive test of the gauge itself is to disconnect the gray wire from the sending unit and ground it. Then turn the ignition on. As oldcutlass said earlier, the gauge should immediately go to E. If it does, and then goes to F when you unground the gray wire, the dash gauge is working fine.

You said in the first comment above, though, that it went to F when the wire was grounded with the ignition on. That's not good as it indicates the dash gauge itself is not working properly. Perhaps where the gray wire connects to the gauge is bad.