Fuel gauge issues on 1966 mustang

[Baba Ganoush]

It has never read "full" since I finished the restoration a 1 1/2 years ago. All new wiring, tank, and sender in tank. Original gauge.

I ground the sender wire to the frame: gauge goes to full

I hook the float/sender up to the wire, ground the assembly and push the float all of the way up: gauge goes to full.

I put the float in the tank, hook up the sender wire, fill it up: only shows half full

After a few gallons burned the gauge just sits on empty and I get play the "when will it be empty" game.

I've pulled it apart more than four times, tested as described above, even tried a new float assembly; nothing. I'm damn tired of smelling like gas and looking for thoughts on this. The only thing I can think of that might be screwing me is the tanks' ground to the body. I painted the tank prior to install, so I'm not sure if it's getting a good ground, or how I'm going to clean the mounting surface off now lol! If I ohm it out with my multimeter, how much resistance is too much, causing a faulty reading at the gauge?

[Z06killinsbf]

I had a similar issue but opposite (read full for too long). I had to bend the float arm to an educated guess and it's better. I think the reading is 75 full to 10 empty.

[Baba Ganoush]

Well that's odd. Damn Taiwanese parts. So I guess I'll just have to take it out again and meter it out with the correct values, eff with it until it gets there. Fun fun!

Resistance from a bolt through the tank - to the body is almost an ohm, you think that's too high? I used that 3M strip-caulk between the tank/body so the bolts are the only ground, and the tank is painted. Not sure if that might affect it.

[Chas_svo]

Try a ground strap?

[Baba Ganoush]

I might try that first, easy test and it's better than taking the float out......again.

Although a problem with a cheap ass part is highly likely. I wish I could find a better quality float assembly.

[homealone]

It could be a mismatched sending unit. A lot of the replacement tanks are 16 gallon vs the original 14gal. They use different sending units. Do you remember which ones you bought?

[mustangguy289]

I have feeling this is a float issue and not an electrical/ground issue. The float is not being allowed to float all the way to the top to give a reading of "full". Try what someone suggested earlier and maybe bend the float.

[Baba Ganoush]

Well I tried a ground strap and that didn't do it.

It could be a mismatched sending unit. A lot of the replacement tanks are 16 gallon vs the original 14gal. They use different sending units. Do you remember which ones you bought?

Well I bought the replacement 16gal tank w/drain in a kit that included the sender. I have since replaced the sender/float assembly with no change. I wish I would've known more about this before I trashed the OEM stuff, dammit!

I have feeling this is a float issue and not an electrical/ground issue. The float is not being allowed to float all the way to the top to give a reading of "full". Try what someone suggested earlier and maybe bend the float.

I think that you're right. I filled it up and drove it yesterday and it seems to stay on the half mark for quite a while. However, it seems I can still drive for some time after it hits E, more than I would think. I still need to ohm it out full and empty and check my readings.

I'll just have to drain it, remove the neck so I can see what's going on in there. What a PITA. Oh, and the way it seals sucks too. I've had a leak after adding gas that required draining it and re-setting the seal and ring on the sender.