Re: Fuel Sending Unit

dodge-him wrote:
> This is not my forta but I think there is a resister in your dash
> cluster that gets weak and causes the low reading. I too put a new
> sender and pick up in the GTX years ago  made sure  it was grounded
> properly to body and it still only read  3/4 when full. but I've read
> of the resister fix over the years. I never bothered and I have a fuel
> cell now!
> Dodgeboy
> 
> 
I have a replacement dash panel with all the instruments that I bought
  off of Ebay and the wiring diagram. I do not see any resistor. It will
  occasionally show a full tank. I think that the problem is either the
  fuel unit or the instrument voltage regulator.
The instruments use a odd movement that has a thermal spring that moves
the needle pro****tionally to the voltage applied. The advantage of this 
is that the reaction time of the meter is slow, so when fuel moves in the
  tank the meter takes the average giving a better reading. Also the 
voltage regulator is mechanical in nature,using a thermal switch that
  opens/closes at a rate that takes the 12 V battery voltage and gives a
  duty cycle that averages out to be 5 V. If the regulator is bad it will
  cycle at the wrong speed or it will stop cycling and apply the full 12
volts across the instrument. That would peg the meter and eventually 
damage it.
I have a replacement voltage regulator that has had its insides gutted
  and replaced with solid state voltage regulator. Also I have taken out
  of replacement dash the temperature and fuel meters, so I can sent them
  out to be tested and calibrated. I will replace the old instruments 
with the newly calibrated units.

F E Fuller