On my 68 coupe, it only reads a quarter of a tank when full. The sending unit is new, and when I put a meter on it, it pulses. Anyone have a clue?

 

My sending unit is new as well, and my gauge registers 3/4 full when the tank is actually completely full. You probably need a new gauge.

 

I had to adjust the float arm lever on mine to get the new sending unit to give an accurate reading. My 67 coupe sending unit had a screw on it to make that adjustment...you might try it if you didn't adjust already..

 

Perhaps someone with more knowledge on this than I can be more specific. -

I believe there is a way to calibrate the guage(?) depending upon the resistance range of the fuel sender. Call the part supplier and ask what the resistances on the fuel sender are at Full and Empty settings (resistance is measured in Ohms). This may be the problem.

Again, I defer to those more knowledgable than I but investigate this if you do not have any more input!

 

I am going to try something tomorrow and I'll let you know how it goes. It was mentioned in a previous post that if you disconnect the wire from teh sending unit, the needle should swing fully one direction. Then if you get a good solid ground, the needle should swing fully the other direction. If the needle fails to go all the way to full, it would be logical you have a bad gage. If the needle swings to full, then it would be something with the sending unit. Does that make sense?

 

That's why I said he probably needs a new gauge. If he is registering anything at all, the sending unit is working. I bent my float armevery which way to try to get the gauge to read full and it never did.