fuel gauge

[sodfather]

my fuel gauge indicates full all the time . whats the procedure for checking the gauge and sender . thanks for any help  .
   
  Ken

[RICH MUISE]

probably another place I'm jumping in when I shouldn't, but have you checked the sender (access thru the trunk) to make sure it's not just hung up? When mine was on the road, it never worked, but never moved off the below empty mark, which is why I'm thinking your's may just be stuck at the top.
Rich

[Tom S]

Kinda looks like you gotta pull the sender.  Seems like there should be an easier way.  Maybe if you had some type of rheostat that would give you the same resistance range  ....?
Also could be that the wire from the sending unit is grounded, making the gauge read full all the time.

From a 1958 Edsel service manual.  Let me know if these pix are not clear enough, I can redo them.







From this thread...
http://57fordsforever.com/smf/index.php?topic=40.0

Ford used the same resistance range for several years, maybe something from a '60s or '70s car could be used.  My Ranchero doesn't have the stock tank anymore, so I don't have this issue.  I have a modified '80s T-Bird tank and sender, it works fine with the stock '67 gauge.

Same resistance range?  See this for those ranges & more info on testing.
http://www.fordification.com/tech/fuel-sending-units.htm

[lowrider]

Unplug the sender in the tank. If the gauge goes to empty the problem is in the sender area. If the gauge stays at full you probably have a short to ground in the wire that runs from the gas gauge to the sender.

[Ford Blue blood]

What they said....the gauge is a small amp meter.  The fuller your tank is the lower the resistance the sender has. and as you might imagine the emptier the tank is the higher the resistance.  So, given it reads full with the switch on (assuming it goes to empty with the switch off) the primary suspect will be the wire/sender.

[sodfather]

O K , checked the wiring , it's okay  the problem is in the sending unit . when I removed the unit it was pretty well corroded inside and out .
a new sender will be on the way . thanks for the help .

[sodfather]

I have more electrical problems , now the fuel gauge fluctuates slowly between full and half while the temp gauge proceeds to peg on hot .
any ideas from the forum ? . thanks , Ken

[gasman826]

Same thing.  Unplug...if they go to empty or cold, problem in the sender.  After unplugging and problem continues, short in wire (temperature gauge), the gauge itself (fuel), or regulator.  Check regulator with test light.  One side 12v constant and the other side 12v alternating 12v and 0v.

[sodfather]

ok by regulator Im thinking  you mean something other than the voltage regulator .

[Tom S]

ok by regulator Im thinking  you mean something other than the voltage regulator .

I think Gasman is talking about the Fuel Gauge Voltage Regulator.  Look at those pix from the 1958 Edsel service manual that I posted in reply #2.  It's in there.  Figs #120 & 121 & a description of it's operation under Fuel Gauge System.  Should be about 5 volts going to the gauge from the regulator.

[sodfather]

Thanks guys , wiring is not my favorite thing but never to old to learn .