Fuel Gage problem??

[68rt]

Hi all, Just finished my 68 R/T restoration and after hearing the horror stories of using a reporduction sending unit, I opted to have the original one rebuilt. I've taken Ohm reading with the tank near empty, 1/2 full and full and the sending unit is putting out the correct ohms at the various levels. I've installed new fuel lines, fuel tank and fuel grounding strap. The problem is when I fill the tank, the gage goes to the full mark as it should. After I use about 5 or 6 gallons of fuel the gage goes to empty or just slightly above for the rest of the tank. I've had the dash gages rebuilt by Red Line Gage Works and have sent it back and everything checks OK. Any thoughts!

 

[moperformance]

Where are you taking the readings at? You can hook up a pot (variable resistor) as a rheostat and dial in the resistance so the gauge will think it's seeing the tank sensor. do this at different positions in the cars circuit. ie: at tank, at the connector in the drivers kick panel and at the gauge to see if the wiring and/or connectors is suspect? remember it's 40 years old

 

[68rt]

The reading I took were at the sending unit, just to verify the unit is suppling the right amount of resistance. Not sure what a pot is or where to get one? Please advise! I guess I'm gonna be checking from the tank wire to the gage with the pot??? Is the current in this circuit running from the tank/ground to the gage, or from the voltage supply at the voltage limiter to the tank? And yes, you make a good point about checking the circuit and connections between the dash and the tank. Thanks Bill for your help, Nick

 

[tpodwdog]

A pot IS A POTENTINOMETER... think of it as a volume knob....the more you turn it ...the louder it goes. the more you turn the "pot" the less the resistance. like a spigot on your garden hose.

 

[68rt]

Got it and thanks for the help, The car is bagged for the winter.

 

[bigmanjbmopar]

Hi all, Just finished my 68 R/T restoration and after hearing the horror stories of using a reporduction sending unit, I opted to have the original one rebuilt. I've taken Ohm reading with the tank near empty, 1/2 full and full and the sending unit is putting out the correct ohms at the various levels. I've installed new fuel lines, fuel tank and fuel grounding strap. The problem is when I fill the tank, the gage goes to the full mark as it should. After I use about 5 or 6 gallons of fuel the gage goes to empty or just slightly above for the rest of the tank. I've had the dash gages rebuilt by Red Line Gage Works and have sent it back and everything checks OK. Any thoughts!

You said yo had the gauges rebuilt? what about the cluster its self? meaning the circuit board on the back along with the voltage limiter and relay? If so have you made sure the wire on the connector are good? also the pins on the board?

Also my fuel gauge was wacky for two reasons one cluster circuit board broken trace and two the gauge itself needed calibration. If you ever pull you gauge out look on the back you will see two small holes top and bottom look closely there are tips of a gear showing through the hole these are used to make the set points on the gauge i.e. full and empty, mine was way off. all better now. Good luck.

 

[68rt]

thanks for your reply, the gage and entire circuit board and instrument cluster was rebuilt and calibrated by Just Dashes in California, infact they took a second look at the fuel gage circuit and rechecked it when I sent it back the second time. I will be back on this project in the spring, as the car is now in winter storage.... Tanks again,

 

[green1]

There are, I think, 2 or 3 different senders, ohms are different. If you can't find it on-line, let us know. Seems you want 90 to 10 sender, can't remember, verify what they gave you.