Full fuel tank only gets the guage up to about 5/8 reading. Fuel use and guage movement seem to correspond but I've yet to drive the guage needle below the "E" so can't be sure if consumption / guage movement is linear all the way to dry tank. Sending unit? If yes, is there any adjustment involved with new unit or is it as simple as shop manual makes it look? Pony is 69 Fastback, I believe with original tank. Thanks.

 

check if sending unit is right side up and not tilted in an awkward position. it may need to be replaced. or the gauge is off but its more likely to be the sending unit

 

You can also test the gauge without replacing it to see if it's bad. I don't remember off the top of my head the procedures but if you do a search you should be able to come up with them. That will help you eliminate that.

 

The sending unit has a tab on it which regulates the float movement. If you bend that tab you will see a difference.

 

sounds like yer float is off.

 

where is this tab?

 

my guage peaks out at just under 3\4 full. definatley need to add it to my list of minor things to fix. with these older cars that list never goes away. [8D]

 

If you look where the float attaches, you will see the adjustment tab.
http://www.metropartsmarket.com/cata..._c15_2898.html

 

heh, on my 68 coupe the fuel gauge reads full until you have about a gallon of gas left. then it just drops down to E

 

I have the exact problem as Nasty69. I have not replaced the sending unit because I was affraid it might be the constant voltage regulator in the instrument cluster, but I can not get the damn cluster out to check the voltage to the guages. My hands are to big to get to the back of the cluster to unplug all the wires. Is there an easier way to check which is at fault? I am leaning to the regulator being the problem because the temp gauge might show low also. It is at the cold mark but I have a 160 deg thermostat in so it should show a little low. That just seems to low. Any thoughts? Ideas?